Regional cancer cytogenetics: A report on 1,143 diagnostic cases

ELSEVIER

Regional Cancer Cytogenetics: A Report on 1,143 Diagnostic Cases

David Perkins, Shawn Brennan, Kelvin Carstairs, Denis Bailey, Dominic Pantalony, Annette Poon, Bernie Fernandes, and Ian Dub

ABSTRACT: The results of studies from a regional cancer cytogenetics diagnostic service are reported. In a l O-year period, 1,143 marrow samples from patients with newly diagnosed leukemia and myelodysplastic syndrome were referred. Successful studies were completed on 992 cases (87%). Among all referred cases, the rates of detection of cytogenetically abnormal clones were 95% for chronic myelogenous leukemia (CML), 54% for acute lymphoblastic leukemia (ALL), 51% for acute myeloid leukemia (ANLL), and 43% for myelodysplastic syndrome (MDS). Of 169 cases of CML studied, 90.5% bore the standard Philadelphia chromosome (Ph), 3.55% had an unusual Ph, and 5.33% were Ph-negative. Among the 59 cases of cytogenetically abnormal MDS, common abnormalities observed were trisomy 8 and changes resulting in loss of material from the long arm of chromosomes 5 and 7, and 20q-. Of the I68 abnormal ANLL, there was a strikingly non-random pattern of aneuploidy, with monosomy 7 and trisomy 8 predominating. Common structural changes observed were changes resulting in loss of material from the long arm of chromosomes 5 and 7, trisomy 8, rearrangements of 1 lq23, t(15;17), t(8;21), rearrangements of 12q13 and 3q, inversion i6, trisomy 1I, Ph, trisomy 21, t(6;9) and t(1;22). The differences between adult and pediatric findings were minor, with the exception of chromosome 5 abnormalities, which were common among adults with ANLL but rare in the pediatric cases. There were 273 ALLs with abnormal cytogenetic findings. There was preferential gain of chromosomes 21, X, 14, 6, 4, 18, 17, and 10 (in decreasing order of frequency)in leukemic clones. Of the 193 ALLs with structural changes, many fell into well-defined categories with established correlations to FAB subtypes. Common changes in ALL were rearrangements of 913, 1213, 6q, TCR loci, 1Iq23, Ig loci, and 8q24, and duplication of lq, Ph, i(17q), t(1;19), i(9q) and dic(9;12). The detailed documentation of the cytogenetic findings in this relatively large, single-institution study will likely facilitate the further characterization of rare, primary cytogenetic changes associated with leukemias and MDS. From a managed health care perspective, regional cancer cytogenetic services may be cost- effective alternatives to single-institution laboratories. © Elsevier Science Inc., 1997

INTRODUCTION

The last decade witnessed the evolution of cancer cytogenetics from a new disc ip l ine wi th uncer ta in cl inical appl ica- t ions and l imitat ions to its present role as an essential component in the armamentar ium of diagnostic investigations now used routinely in oncological pathology [1].

From the University of Toronto Hospitals' Cancer Cytogenetics Program (13. P., S. B., I. D.), The Toronto Hospital, The Hospital for Sick Children (A. P., L D.), Mount Sinai Hospital, and the Departments of Medicine, Pathology and Pediatrics, University of Toronto, Canada.

Address reprint requests to: Ian D. DubS, Ph.D., University of Toronto, Sunnybrook Health Science Centre, Department of Lab- oratory Medicine, E3-43, 2075 Bayview Avenue, Toronto, Canada M4N 3M5.

Received July 31, 1996; accepted October 2, 1996.

Cancer Genet Cytogenet 96:64-80 (1997) © Elsevier Science Inc., 1997 655 Avenue of the Americas, New York, NY 10010

From an academic view, molecular dissections of transloca- t ion breakpoints contributed more to our understanding of the biology of cancer than any other endeavor during the late 1970s and the 1980s [2-6]. In the context of clinical laboratory medicine, leukemia diagnosis has been refined from a purely morphological art to a scientific assessment based on morphology, immunology, and cytogenetics.

Several issues have been resolved over the last decade. The scope and depth of cancer cytogenetics in hematological mal ignancy are fairly wel l -e luc ida ted [7-9]. It is l ikely that most of the common (i.e. > ~ 3 % incidence) acquired chromosome changes associated with specific cl inico- pathological enti t ies have been defined. Primary, secondary, and tert iary acquired changes have been descr ibed in all leukemias. Genetic changes associated with specific c l inical courses and outcomes are descr ibed for all hematological malignancies. As t reatment opt ions cont inue to evolve, it is l ikely that acquired genetic changes in cancer

0165-4608/97/$17.00 PII S0165-4608(96)00363-9

Regional Cancer Cytogenetics: A Report 65

will play an increasingly important role in patient care, particularly with the likelihood of bona fide cancer gene therapy in the near future [10].

By the turn of the century, most clinically relevant acquired chromosome changes in leukemias and myelodysplastic syndromes will probably be characterized at the molecular level. Thus, molecular genetic testing may be incorporated into an increasing number of cases cur- rently referred only for diagnostic cytogenetic testing. The extent to which molecular genetic tests will complement or replace cytogenetic tests will likely be determined by eco- nomic considerations and fundamental differences in the type of information provided. For example, cost-effective, PCR-derived molecular evidence for a BCR/ABL rearrangement may be the only genetic test required in typical cases of chronic phase CML [4, 11, 12], with cytogenetics reserved for cases in which additional investigations are required or disease progression or response to therapy is an issue. On the other hand, in acute leukemias and myelodysplastic syndromes where diagnostically and prognostically important structural and/or numerical changes are often encountered, cytogenetic investigations will continue to be necessary.

Genetic-based testing in oncological pathology is cur- rently offered in several settings. In many centers, the service is incorporated as an adjunct to what were initially prenatal diagnostic genetic testing laboratories run by laboratory directors with little expertise or interest in oncology. In other centers, cytogenetic and molecular genetic laboratories perform only oncology services. Medical insurance considerations often play a role in determining whether or not genetic-based diagnostic testing is performed.

Since 1984, cancer cytogenetics at the University of Toronto teaching hospitals has developed as a separate facil- ity. The service is exclusively for oncological pathology and was initially funded extra-globally by the Ontario Ministry of Health. We report herein our first 10-year experience with all leukemias and myelodysplastic syndromes referred to the regional program from three area hospitals. These data are of interest to researchers continuing to explore the molecular basis of neoplasia; clinicians, scien- tists, and laboratory directors concerned with quality as- surance in cancer cytogenetic services; and health care resource planners considering the merits of specialized regional diagnostic laboratory services.

MATERIALS AND METHODS

All patients were referred from one of three tertiary/quaternary care hospitals--Toronto's Hospital for Sick Chil- dren, The Toronto Hospital (formerly Toronto General Hospital and Toronto Western Hospital) and Mount Sinai Hospital--during the period 1984 to 1994. Diagnoses were made using standard FAB criteria [13] by the referring hospitals' hematology service and reviewed by the hemato- pathologists and immunopathologist involved in this study (K.C., D.P., D.B., A.P., B.F.). In the large majority of cases of acute leukemias, the lineage designation was confirmed by cell marker analysis using a combination of flow cytometry and immunocytochemistry. Rare cases with

mixed lineage or ambiguous phenotypic markers were assigned to diagnostic subgroups, by consensus. All cytogenetic studies were done on bone marrow samples aspi- rated for routine diagnostic studies. Samples for cytogenetics were collected by a technologist at the bedside. In most cases, both direct (uncultured) and 24-hour cultures were initiated and harvested according to standard techniques [1]. Analyses of G-banded metaphases were done according to international criteria [14] by registered cytogenetic technologists. The outcome of a particular case was classified as "abnormal" if an abnormal clone was detected, or "normal" if undetected after the analysis of at least 10 metaphases from the direct harvest and 10 from the 24-hour culture. ISCN criteria were used to define abnormal clones. "Nor- mal" and "abnormal" results were considered successful analyses. Finally, cases in which either no metaphases were obtained for analysis or ones in which only normal metaphases were obtained after the analysis of less than 10 from the direct and less than 10 from the 24-hour culture, were classified as "no result" and, hence, unsuccessful cases. All cytogenetic findings were reviewed by a cytogeneticist (I.D.) and a registered cytogenetic technologist with 10 years of experience in cancer cytogenetics (S.B.). Analyses were at the 350 band resolution level or greater.

RESULTS

Synopsis

There were 169 cases of CML (157 adult and 12 pediatric), 509 cases of ALL (57 adult and 452 pediatric), 327 cases of ANLL (229 adult and 98 pediatric), and 138 cases of MDS (all adult), for a total of 1,143 patients studied at diagnosis. Overall, 13% of samples yielded unsuccessful analyses (Figure 1). In 29% of all cases, there was no evidence for the presence of acquired clonal cytogenetic abnormalities. The remaining 58% of all cases (or 67% of those with analyz- able metaphases) were abnormal. There was substantial variation in results among different diagnostic groups with abnormal rates of 95%, 54%, 51%, and 43% in CML, ALL, ANLL, and MDS, respectively. There was no evidence of acquired clonal changes in 5%, 25%, 39%, and 51% of CML, ALL, ANLL, and MDS, respectively. Insuffi- cient metaphases (no result) for analysis were encountered in 1% of CML, 22% of ALL, 9% of ANLL, and 7% of MDS. If cases with insufficient metaphases for analysis are excluded, the rates of clonal cytogenetic abnormalities are: 95% for CML, 69% for ALL, 57% for ANLL, and 46% for MDS.

There were differences between the overall adult and pediatric results (Figure 1). Among the ALLs, the abnormal rate was 77% for adults and 51% for pediatric cases. This difference was largely accounted for by inadequate samples (i.e., no result) and normal result rates that were substantially higher among pediatric cases (9% vs. 23% for inadequate sample rate and 14% vs. 26% for normal rate, respectively). Among ANLLs, the abnormal rates were almost identical (51% vs. 52%; however, cases with normal results were observed 11% more often in the adult group, while the frequency of cases with insufficient metaphases was 10%

66 D. Perkins et a].

Summary Of Results in 1,143 Diagnostic Samples

o O~

t-

(D n

. . . . 95%

1 0 0 -

90-

80+

70-

60

50

40

3O

20

10

C

' J "0 ' < 13.

Indications for Testing

19 CML 19 ALL :7 ANLL 8 MDS

lal of all cases ~essful cases)

c. < ~ : E; _1 "~ "t:J

< [ 13. . j Z ,<

Testing Outcomes

Figure I Summary of results obtained in the analysis of 1,143 diagnostic cases. The percentage of abnormal cases is indicated, using the total cases referred for investigation as the denominator and (in parentheses) only those in which successful cytogenetic studies were obtained.

higher in the pediatric group. If only cases in which successful cytogenetic results were obtained are considered, then the largest difference between adult and pediatric cases is among ALLs: 85% abnormality rate among adult cases vs. 66% for pediatric cases. For ANLLs, this difference is less striking: 54% for adults and 62% for children.

Consistency of Analyses There was no difference between the annual abnormal rates observed between 1986 and 1994. Despite the fact that cytogenetic analyses were performed by over 20 different cytogenetic technologists over the 10 year period, approximately one-half of the cases (579 of 1,143) were analyzed by the same five registered cytogenetic technologists. Among this group, there was no evidence for higher rates of detection of abnormal cases with increased number of cases analyzed (data not shown). For the latter analysis, the assumption was made that the distribution of diagnostic subtypes per technologist was consistent.

CML There were 169 cases of CML, of which 12 were pediatric. The standard t(9;22) translocation was observed in all pediatric cases and in 141 adults. Overall, 153 of the 169 cases bore the standard Ph (90.5%). While all patients presented with chronic phase disease by morphological and hematological criteria, 23 of the 141 adult Ph-positive cases presented with the Ph as well as with additional

changes (13.6% of all CMLs fell into the latter category). In 15 of the latter 23 cases, the additional acquired change was a well-described secondary change in CML [12], while in the remaining eight cases, the additional changes were of a more random nature (Table 1). In six cases (3.55% of all CMLs), a complex or variant Ph was observed (Table 1). Nine cases (5.33% of all CMLs) showed no cytogenetic evidence for rearrangements involving 9q34 or 22q l l but were, nevertheless, positive for a BCR gene rearrangement by Southern blotting. In only one case of adult CML (0.59%), confirmed as Ph-positive in a post-diagnostic investigation, did the initial diagnostic test fail to provide an acceptable result by ISCN standards [14]. Some of the above cases of Ph-negative CML and CML with complex Ph translocations were included in a previous report from this laboratory [15].

MDS There were 138 cases of MDS of which informative cytogenetic studies were obtained in all but nine (93% success rate). In 70 patients (51% of all MDS), there was no evidence for the existence of acquired clonal cytogenetic abnormalities. Of the abnormalities observed in the remaining 59 cases, trisomy 8 was detected most commonly (18 cases), followed by rearrangements giving rise to complete or partial long-arm monosomies for chromosome 5 (15 cases) and similar rearrangements of chromosome 7 (12 cases). Other changes observed, and known to be non-randomly associated with MDS [16, 17] were: long arm deletions of chro-


Table I Atypica l cytogenetic f indings among 169 CMLs at diagnosis

Complex or variant Ph Secondary acquired changes a

No. t(6;9;22)(p21;q34;q11) +8 3 t(9;22;lO)(q34;q11;p13) +8 b 2 t(9;22;10)(q34;q11;q24) i(17q) 2 t(14;22)(q32;q11) i(17q) b 2 t(1;9;22)(p32;q34;q11) +Phl 2 t(1;9;22)(q25;q34;q11) _yb 2

- Y 1 +19 1

Random clonal changes observed in addition to the Ph

t(1;19)(p36;p12) b de](12)(p13) del(1)(p13) t(12;16)(q24;p13) b t(2;19)(p13;p11) b +14 inv(3)(q21q26) b add(17)(p11.2) del(5)(q13q33) del(17)(p11) inv(6)(pllp25) t(17;20)(p13;q11) b del(7)(q11.2q22) b t(1;18)(q22;q21) t(7;17)(q11;p12) h ÷20 t(7;19)(q22;p13.3) ~' ÷21 t(8;21)(q22;q22) del(X)(q24)

In addition to the standard Ph, several cases presented with variant or complex translocations as well as additional acquired changes. These changes are indicated in the table. Additional acquired changes at diagnosis are listed as either belonging to the well-accepted group of secondary changes often seen in course of progression of CML or as being of a more random nature. *'Observed in 23 cases with standard Ph and additional acquired changes. All above cases are from adult patients. t'Cases in which the acquired abnormality was the sole additional change.

mosome 20 (6 cases); rearrangements involving 12p (4 cases); t r isomies 11 and 13 (3 cases each); whole arm translocat ions involving chromosomes 1 and 7 (3 cases); rearrangements involving 3q21-26 (2 cases); and t(8;21), de l ( l lq23) , del(13q14), and t r i somy 21 all observed in one instance each (Figure 2). Structural changes observed only once and which are not strongly associated with relevant c l inico-pathological enti t ies are l is ted in Table 2.

The dis t r ibut ion of non- randomly acquired changes among MDS FAB subgroups is shown in Figure 2. Whi le the numbers are small, some features are interesting. Tri- somy 8 was rela t ively non-specif ical ly associated with FAB subtype. On the other hand, rearrangements involving chromosome 5 were more frequent in the RA and RAEB subgroups than in CMML and RARS. Similar rearrangements involving chromosome 7 were most frequent among the RAEBT group.

ANLL

There were 327 cases of ANLL (229 adult and 98 pediatric). Cytogenetic studies were successful in 297 (215 adul t and 82 pediat r ic cases). Clonal chromosomal abnormal i t ies were detected in 117 adul t and 51 pediat r ic cases. The numerical abnormalities observed among the 168 abnormal cases were clear ly non- randomly dis t r ibuted (Figure 3). Monosomy 7 and t r i somy 8 were far more frequently

observed than any other aneuplo idy . Other aneuplo id ies observed more frequently than might be pred ic ted on the basis of random events were monosomies for chromosomes 3, 5, 17, 18, and Y and tr isomies for chromosomes 11, 21, and 22. The main difference noted between the distribution of aneuplo id ies among adul t and pediat r ic cases was an excess of acquired t r i somy 21 among the pediatr ic cases (Figure 3).

Acqui red chromosome changes observed among the 168 cytogenetically abnormal ANLL cases were categorized as belonging to one of the following groups: rearrangements giving rise to complete or part ia l long-arm delet ions of chromosome 7 (35 cases), similar rearrangements of chromosome 5 (25 cases), t r i somy 8 (23 cases), rearrangements involving 11q23 (19 cases), t(15;17)(q22;q11) (16 cases), t(8;21)(q22;q22) (12 cases), rearrangements involving 12q13 (7 cases), rearrangements involving 3q21 or 3q26 (6 cases), invers ion (16)(p13q22) (5 cases), t r isomy 11 (4 cases), Ph (4 cases), trisomy 21 (3 cases), t(6;9)(p23;q34) (3 cases), and t(1;22)(p13;q13) (1 case) (Figure 4a).

Of the above 14 categories, four showed variations in the specific cytogenetic change (changes involving chromosomes 7, 5, 11q23, and 12q13) and these ind iv idua l rearrangements are deta i led in Table 3. Of the 35 cases classif ied as del/t(7q) & - 7 , 19 were monosomy 7. In only two of the 19 was monosomy 7 the sole change. There were two translocat ions in this group, both involving 7q11. There were 12 chromosome 7 long-arm delet ions, wi th q22 and q31 being the most common breakpoint and all but one result ing in loss of mater ial p roximal to 7q32. Of the 25 cases classif ied as del/t(5q) & - 5 , seven were monosomy 5 and in no instance was this the sole acquired change. Of the 12 chromosome 5 long-arm delet ions, five involved breaks in 5q13. The five chromosome 5 long-arm translocat ions involved breaks in q15, q22 (2 cases), and q35 (2 cases). Eight of the 19 cases of del/t(11q23) were t(9;11)(p22;q23). Two were t(10;11)(p13; q23) and one was t(11;19)(q23;p13). Two 11q23 rearrangements involved translocat ions wi th unident i f iable par tner chromosomes . The cases g rouped as inv/ t /de l (12q13) included two inv(12)(q13q24), two deletions, and two translocations, the latter four wi th breakpoints in 12q13.

The distr ibution of recurrent changes among FAB subtypes showed a non-random pattern (Figure 5). Trisomy 8 and rearrangements of 7 and 5 were clearly non-specific markers, as they occurred in almost all FAB subtypes. Rear- rangements of 11q23 were seen in mainly M2, M4, and M5 subtypes. Of the 16 t(15;17) translocations, 15 were M3 and one was MO. ANLLs with t(8;21) were generally M2 and, less often, M1. Rearrangements of 12q13 tended to be among M1 and M2 subtypes. Inversion 16 cases were M4 except for one M1 and one case in which it was observed in an M3, also with t(15;17). Rearrangement 3q cases were over-represented among MO ANLL, but this abnormali ty was also detected in M5, M6, and M7 ANLL. Trisomy 11 as the sole change was observed in 2 cases of M1 and 2 of M2. The Ph was seen in three cases of M1 and one of M7. One case of acquired t r isomy 21 was observed in M1, M2, and M7 subtypes. Three cases of t(6;9) were seen in M1, M2, and M7 ANLL. The sole t(1;22) was a case of M7 ANLL.

68 D. Perkins et al.

C o m m o n Structura l C h a n g e s in 59 A d u l t M D S Wi th A b n o r m a l C l o n e s

u)

.2 p.

J~ o

JD E ,,-z

Z

1 8 -

1 6 -

1 2 -

1 0 -

6 -

4 -

2 -

[ - - _ _

o - ~ tn I ........... .....

® ~ ~ ............... ................ > '~ A

u Cytogenetic Changes

FAB Subtype

Figure 2 The structural changes known to be associated with MDS and detected in the course of cytogenetic studies on 138 cases of MDS are shown. Of the 138 cases, 59 were cytogenetically abnormal. The distribution according to FAB subtype is also indicated. In addition to these recognized changes, non-recurrent changes were also observed (see Table 2).

Comparison of the changes observed in adult and pediatric ANLL provided no obvious evidence for fundamenta l genetic differences be tween the two groups (Figures 4b and 4c), wi th the following exceptions: monosomies and rearrangements involving chromosome 5, the second most common change acquired in adul t ANLL, were not seen in

the pediatr ic popula la t ion; pediat r ic cases wi th rearrangements of 11q23 tended to be M2 or M4, whi le among adults they were more likely to be M5; and inversion 16 cases, whi le exclus ively M4 in the adul t popula t ion , were also detected in M1 and M3 pediat r ic cases.

Ninety-five structural changes not wide ly accepted as

Table 2 Non-recurrent changes among 59 adul t MDS with abnormal cytogenetics ~

add(1)(p32) t(2;8)(p13;q24) del(3)(p13) del(4)(p12p14) del(1)(p32p36) del(2)(p11) add(3)(pll) t(4;6)(q13;q21) t(1;11)(q44;q13) add(3)(q21) b t(4;20;17)(q21;p13;p13)

inv(3)(q22q27) b

add(5)(p13) add(6)(p23) b del(7)(p15) add(8)(q22) add(6)(q13) t(7;19)(q11.2;p13.3) del(8)(q22)

r(7)(pllq36) b

del(9)(p22) add(12)(p13) del(16)(p13.1) add(17)(p11) b t(9;13)(p24;p13) inv(12)(p12q22) t(17;20)(q25;q13.1) del(9)(q22) add(12)(q24)

add(19) (q13) del( 20)(p 11) add(21 )(p 11.2) del(22)(ql 3) del(X) (q24)

Several changes, in add i t ion to those wel l -character ized in MDS, were observed among the 59 cytogenet ical ly abnormal cases, a n d these are shown here. Cases are arranged in the table by the cytogenetic address of the abnormality: l p in the top left and 22q and the sex chromosomes in the bottom right-hand side of the table. Cases in wh ich the abnormali ty was the sole acquired change are indicated.

~All changes were observed only once.

~Cases in w h i c h the abnormal i ty was the sole s t ructural change.


Aneuploidies Acquired in 168 ANLLs With Abnormal Cytogenetics

34

22

18 c o cu 14 P

0 "6 6

E 2.

Z 2 -

6 .

10.

14,

18

Chromosome gain

Chromosome loss

1 2 3 4 5

• Pediatric

41 Adult

6 7 8 9 10 11 12 13 14 15 16 17 18 19

Chromosomes Gained (upper) or Lost (lower) 20 21 22 X Y

Figure 3 Gains and losses of whole chromosomes observed in 168 ANLLs with abnormal cytogenetics. Gains are indicated above the horizontal line and losses below. Pediatric and adult cases are indicated. In only two instances did the same clone exhibit tetrasomy (or greater amplification) for a particular chromosome.

non-random changes acquired in hematological malignancy were also observed among the 168 ANLLs with structurally abnormal leukemic clones. These cytogenetic changes and the FAB subtype within which they occurred are noted in Table 4.

A L L

There were 509 cases of ALL (452 pediatric and 57 adult). Cytogenetic studies were successful in 398 cases (346 pediatric and 52 adult). In total, 273 cases were cytogenetically abnormal. Of these, 144 included numerical changes. The aneuploidies observed were strikingly non-random (Figure 6). Extra copies of the following chromosomes were observed far more often than other aneuploidies: 21, X, 14, 6, 4, 18, 17, 10, and 8 (in descending order of frequency). Monosomies were relatively rarely encountered and followed a more or less random pattern with respect to the particular chromosome lost.

Of the 144 cases with numerical changes, 64 also bore structural changes. In addition, there were 129 pseudodip- loid ALLs with structural changes. Thirteen types of structural changes were observed recurrently among the 193 cases of ALL with acquired structural chromosomal changes (Figure 7 and Table 5). The categories of structural changes (and number of times the changes were observed) are: rearrangements involving 9p (37), 12p (25), 6q (23), the T-cell receptor loci (7p15, 7q36, and 14q11) (23), 11q23 (23), the immunoglobulin heavy and light chain genes (14q32,

2p11, and 22q11) (18), 8q24 (12), duplications involving l q (11), Ph (10), i(17q) (6), t(1;19) (6), i(9q) (5), and dic (9;12) (3).

Of the 9p rearrangements, involvement of 9p13 was most common and observed in two cases as the sole change in the form of a terminal deletion, in seven cases as terminal deletions with other cytogenetic changes, and in five cases as a translocation (Table 5). Three of the transloca- [ion cases were t(9;17)(p13;q21). Recurrent 9p changes were also noted at p22, p21, and p11. The rearrangements involving 12p were more heterogeneous, with nine cases involving deletions and translocations at p13, eight involving each of p12 and p l l (excluding the three dic(9;12) cases). Rearrangements involving 6q were most common at 6q21 (17 of 23 cases). Deletions at 6q21 were more common than any other type of rearrangement. Involvement of the T-cell and immunoglobulin receptor gene loci were heterogeneous. Of note were examples of translocations in which both breakpoints coincided with Ig or TCR gene loci; t(2;7)(p11;p15) and t(2;14)(p11;q11); and translocations known to involve loci of characterized oncogenes: t(10;14)(q24;q11), t(11;14)(p13;q11), t(14;18)(q32;q21), t(8;14) (q24;q32), t(8;22)(q24;q11) and t(8;14)(q24;q11) [2, 18, 19]. The t(10;14) and t(2;14) cases have been the subjects of previous reports from this laboratory [20, 21]. Ten of the 23 11q23 rearrangements were t(4;11)(q21;q23). There were also two cases of t(1;11)(p32;q23), two of t(11;19)(q23;p13), and what is probably a three-way variant of the latter translocation, t(11;17;19)(q23;q21;q13). Eight of the 11 cases of duplica-


tions in the long-arm of chromosome 1 involved a break at lq21; all resulted in duplication of lq24.

Ninety-five structural changes, not widely accepted as non-random changes acquired in hematological malignancy, were also observed among the 193 ALLs with structurally abnormal leukemic clones (Table 6).

The distribution of the recurrent changes acquired among pediatric and adult ALLs classified as T-cell, B-cell, and B-precursor are shown in Figure 7. All but one of the 37 cases with rearrangments involving the short arm of chromosome 9 were B-precursor ALL. The exception was a pediatric case of T-cell ALL. Rearrangements of 12p were exclusively among B-precursor ALLs. Rearrangements involving the TCR gene loci were more heterogeneous, with 10 of 23 cases being T-cell and the remainder B-precursor ALL. In contrast, only one case of 18 with rearrangements involving Ig loci was T-cell ALL; the remainder were B-precursor ALL. Rearrangments involving 11q23 were B-precursor ALL in 22 of 23 cases. Translocations involving 8q24 were B-cell ALL with the exception of one case of a t(8;14)(q24;q11) occurring in T-ALL [21]. Cases with the Ph, i(17q), i(9q), and dic(9;12) were all B-precursor ALL. With the exceptions noted in Table 6, all cases with non-recurrent structural changes were B-precursor. Differences between adult and pediatric cases with respect to the distribution of cytogenetic subtypes among ALL phenotypes were not possible to assess in light of the small sample sizes.

DISCUSSION

The cytogenetics of leukemias and myelodysplastic syndromes have been reviewed extensively [1, 6-9, 17, 19, 22- 30]. This report of cytogenetic testing done at diagnosis for patients with hematological malignancy is significant for the following reasons: there is a lack of ascertainment bias, as cases were consecutive referrals to a regional laboratory service; the methodology used throughout was consistent; the disease subtypes were classified using strict criteria; and there were a relatively large number of cases exam- ined. The key points to emerge from the data analysis relate to the rates at which chromosomally abnormal clones were detected among this group of cases, the speci- ficity with which particular abnormalities were observed among disease subtypes, and the documentat ion of specific abnormalities which may constitute new clinico-pathological cytogenetic markers.

Abnormal Rates

Much emphasis has been placed on the rates at which abnormal clones are detected in cancer cytogenetics [31]. However, many factors could influence such data, including the diagnostic case mix, ascertainment bias, methodological considerations, and geographic considerations. In the present study, abnormal rates for CML, MDS, ANLL, and ALL were 95%, 43%, 51%, and 54%, respectively. The

Figure 4 The occurrence of well-characterized recurrent changes in ANLL is shown for the 168 cases in this data set. The FAB subtype is also indicated here and in Figure 5. Details of cases lumped together in particular categories are shown in Table 3. Combined data for adult and pediatric cases are shown in Figure 4a, adult only cases in 4b, and pediatric only cases in 4c.

a Acquired Recurrent Changes in 168 ANLLs (Adult & Pediatric)

30 : : :M:_ r i M 3

. . . . . . . . . . . . . . . . . . . . . . r - I M 2

2°1111| I I . , , I

Recurrent Changes


b Acquired Recurrent Changes in 117 Adult ANLLs

30 . . . . . . . . . . . . . . . . [] M7 [] M6 ! I IM5 i B M4 1 II11 M3 [

~) 20 I-]M2 BM1 I IM0

r.) 15 . . . . . . . .

10 . . . . . . . . . . . :

2 Recurrent Changes

o o) m 0

3 5 -

3 0 -

2 5 -

2 0 -

1 5 -

1 0 -

5 -

Acquired Recurrent Changes in 51 Pediatric ANLLs

B ~ j [] M6 I I = M 5 - ~ 1 raM4 ] raM3 ! r-IM2 raM1 I iMO

I l

Recurrent Changes

Figure 4 Continued.


Table 3 Detailed analysis of structural changes involving chromosomes 5, 5q, 7, 7q, 11q23, and 12q13 observed in 168 ANLLs

del/t(Tq) & - 7 No. del/t(5q) & - 5 No. de l / t / ( l lq23) No. inv/t /del(12q13) No.

- 7 17 - 5 7 rea(11)(q23) 2 inv(12)(q13q24) 2 - 7 a 2 del(5)(ql l .2q33) 1 del(11)(q23) ° 1 inv(12)(p l lq13) a 1 i(7q) 2 del(5)(q13) 1 t(1;11)(p32;q23) c' 1 del(12)(q13q22) 2 t(3;7)(p21;q11) 1 del(5)(q13q23) 1 t(1;11)(q21;q23) 1 t(5;12)(p15;q13) 1 t(7;13)(q11;p11) 1 inv(5)(q13q22) a 1 t(1;11)(q21;q23) ° 1 t(6;12)(p21;q13) 1 del(7)(q22) 4 del(5)(q13q33) 2 t(4;11)(q21;q23) a 1 del(7)(q22q34) 1 del(5)(q15q33) 2 t(9;11)(p22;q23) a 6 del(7)(q31.2q32) 1 del(5)(q15q33) ~ 1 t(9;11)(p22;q23) 2 del(7)(q31.2q32) ° 1 t(3;5)(p21;q15) 1 ins(10;11)(p12.1;ql 3q23) 1 del(7)(q31.3q34) 1 t(5;6)(q22;q13) 1 t(10;11)(p13;q23) 2 del(7)(q32) 2 t(5;8)(q22;q22) 1 t(11;19)(q23;p13) 1 del(7)(q32) ° 1 del(5)(q22q33) 2 del(7)(q34) 1 del(5)(q31) 2

t(5;17)(q35;q21) 1 t(5;7)(q35;p13) 1

No. of observat ions 35 25 19 7

In Figures 4 and 5, several different cytogenetic changes observed among the ANLL cases are grouped, for logistic reasons. The details of the individual abnormalities grouped together are indicated here.

OCases in which the abnormality observed was the sole structural change.

diagnoses in all cases were confirmed morphologically and by immunophenotypic methods, in the case of acute leukemias. The data set represent consecutive cases referred from regional tertiary/quaternary care facilities

operating under Canada's system of universal health care. All cases were analyzed in the same cancer cytogenetics laboratory licensed by the Ontario Ministry of Health and periodically tested for proficiency under the auspices of a

Figure 5 Acqui red non - r andom changes in the 168 abnormal ANLL cases, s h o w n according to FAB subtype. Details of cases l u m p e d together in part icular categories are s h o w n in Table 3. In addi t ion to these non - r andom changes, several changes not accepted as non- randomly associated wi th ANLL were observed, and these are l isted in Table 4.

Acquired Recurrent Changes in 168 ANLLs According to FAB Subtype

O

m (J

M0 M1 M2 M3 M4 M5 M6 M7

i

i

i

FAB Subtypes

• t(1 ;22) 0t(6;9) l-ltrisomy 21 Dt(9;22) [] trisomy 11 Binv(16) • rea(3q) • inv/t(12q 13) Ut(8;21) Qt(15;17) • del/t/v(11 q23)

trisomy 8 • del/t(5q) & - 5 Udel/t(7q) & - 7


Z

CO

©

Q

Z

~ o ~ X

~ ¢~1 ¢~1 ~:~ ~:3~ ~ ~3 ~

o ~ o ~

~ : ~ ~-7 ~ ~ ~ 3 ~ ~ ¢~

L~

×

z


Aneuploidies Acquired in 273 ALLs With Abnormal Cytogenetics

18o T Chromosome gain

160

140

120 o m > loo ¢p u) J~ O 8 0 "6

" 6O E Z

4 0

I~ Pediatric

• Aault

20,

0.

-20 .L Chromosome loss

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 x Y

Chromosomes Gained (upper) or Lost (lower)

Figure 6 Gains and losses of whole chromosomes observed in 273 ALLs with abnormal cytogenetics. Gains are indicated above the horizontal line and losses below. Pediatric and adult cases are indicated. In several instances, the same clone exhibited tetrasomy (or greater amplification) for a particular chromosome. The majority, but not all, of the above cases fall into the category of hyperdiploid ALL cases with >50 chromosomes.

Provincial laboratory testing program. There was litt le variat ion in annual abnormal rates during the per iod of s tudy and there was no evidence for var iabi l i ty due to variat ions in technical abi l i ty on the part of technologists.

The abnormal rate among the CML cases reported here is entirely consistent with that generally seen in this relatively homogenous group of pat ients [4, 8] and may perhaps be considered a further measure of the sensi t ivi ty and speci- ficity of the cytogenetic testing performed throughout. For the MDS cases, the overall abnormal rate of 43% (or 46% if only successful analyses are considered) is also in keeping with the one-third to one-half inc idence repor ted in most large series [17, 30-37]. The ANLL abnormal rate of 51% observed in this study is almost identical to the 50% figure reported in the Fourth International Workshops on Chromo- somes in Leukemia [38]. However, several s tudies have since repor ted abnormal karyotypes in 70%-80% of ANLL [29, 37, 39-45]. For the ALL cases, our abnormal rate of 54% is also lower than the two-thirds propor t ion repor ted in several s tudies [27, 28, 46-51].

How can we account for the abnormal rates observed for the acute leukemias, par t icular ly pediat r ic ALL, which are lower than s imilar figures from other centers? One may argue that this d iscrepancy is not l ikely due to a technical problem, since the abnormal rates for CML and MDS are not particularly low and these latter samples were handled identically to the acute leukemia specimens. The consistency of the annual abnormal rates further suggests a small l ikelihood of technical artifacts being operative. We suggest

that the abnormal rates observed here may be a true reflec- tion of a unique case mix and a function of geographic or other factors which remain to be defined. For example, it is conceivable that the case mix under a system of universal medica l care may contain a higher propor t ion of referrals presenting at earlier disease stages and with less aggressive forms of disease than may be encountered under heal th care systems in which financial considerat ions influence the timing and extent of diagnostic procedures. Conversely, in reports from centers special iz ing in "catastrophic ill- nesses," there may be a bias toward cases wi th more high risk features, inc luding abnormal cytogenetics. Whi le such phenomena may not affect cytogenetic findings in chronic and pre-leukemic conditions, it may significantly influence observations among the more genet ical ly unstable acute leukemias.

If only cases in which successful cytogenetic studies were obtained are considered, then the abnormal rates for ANLL and ALL are 57% and 69%, which are not significantly different from data obtained in other centers. This would support the view that the incidence of acute leukemia cases in which insufficient metaphases were obtained for analysis (22% for ALL and 9% for ANLL) is a key factor in the relat ively low overall abnormal rates repor ted here for acute leukemias. We could find nothing in our methodological approach to suggest why our procedures may result in a mitot ic index among acute leukemia cases that is lower than that obtained by other laboratories. The possibil- ity that acute ]eukemias with low mitotic indices or normal


A c q u i r e d R e c u r r e n t C h a n g e s in 193 A L L s W i t h S t ruc tura l A b n o r m a l i t i e s

40-

35- I I . . . .

30-

25-

20- -t I

15-

10- .....

0 ....... i .................... i ..........

t - o

P

0

o

,,Q

E Z

- - [ ] T - C e l l Pediatric E]T -Ce l l A d u l t

B L3-B-ce l l Pediatric [ ] L3-B-cell Adult

A b n o r m a l i t i e s O b s e r v e d

Figure 7 Non-random chromosome changes were observed in 193 cases of ALL with structural abnormalities. The distribution of these changes according to FAB subtype is shown for adult and pediatric cases. The basis on which cases were lumped into particular categories is evident from Table 5. In addition to these non-random changes, several changes not accepted as non-randomly associated with ALL were observed, and these are listed in Table 6.

cytogenetics are censured in other studies (through deliber- ate exclusion or inadvertently through referral patterns which result in different case mixes at centers more likely to publish data) must be explored.

CML

The incidence of CML cases in which the Ph was encountered in both the typical (90.5%) and unusual (3.55%) translocation forms is essentially identical to that reported by others [1, 4, 7, 8, 12]. Similarly, the proportion of BCR rearrangement positive, Ph negative cases (5.33%) is consistent with data from others [4, 15]. The proportion of newly diagnosed cases with acquired changes in addition to the Ph is perhaps a bit high, but not unduly so [12].

MDS

There are ,-30 different acquired cytogenetic changes non- randomly associated with MDS [1, 52]. Of these, 13 were observed in our data set of 59 chromosomally abnormal cases. While the numbers are too small to make specific inferences, it is clear that the overall incidence of these changes within our data set and the distribution of changes within the different FAB subtypes is not significantly different from that reported in several studies [17,

32-37, 53]. The reported tendency for abnormalities resulting in loss of chromosome 7q to be associated with more aggressive forms of MDS, and similar abnormalities of chromosome 5q to be associated with more stable subtypes, was apparent in our study.

ANLL

The aneuploidies observed among the ANLLs in this study confirm the well-established correlation of acquired monosomy 7 and trisomy 8 with ANLL [1]. The other chromosomes exhibit a more or less random pattern of involvement, with the exception of numerical changes of chromosome 1 (not observed) and trisomy 21, which was disproportionately represented among pediatric ANLLs. The pattern of aneuploidies for ANLL is clearly different from that for ALL (Fig. 3 vs Fig. 6), as has been previously noted [7]. (Cases with constitutional trisomy 21 were not included in the data.)

The structural changes observed are clearly non-random and different from those seen in lymphoid neoplasia. The most frequent changes are abnormalities resulting in loss of 7q, similar abnormalities of 5q, trisomy 8, t(15;17), rearrangements of 12q13, rearrangements of 3q, inversion 16, trisomy 11, Ph, trisomy 21, t(6;9), and t(1;22). The incidence


Tab le 5 Deta i led analysis of s t ruc tura l changes i n v o l v i n g 9p, 12p, 6q, 11q23, 8q24, dup( lq ) , and TCR and Ig Loci obse rved a m o n g 193 ALLs w i t h s t ruc tura l ly abnorma l l eukemic c lones

t/del(9p) No. t/del(12p) No. t/del(6q) No. rea(TCR) No

t(3;9)(q27;p24) 1 add(12)(p13) 2 del(6)(q13q15) 1 add(7)(p15) 1 t(9;15)(p24;q15)" 1 t(1;12)(p21;p13) 2 del(6)(q13q21) ~.~J 1 inv(7)(p15;q32) ~ 1 add(9)(p23) b 1 t(2;12)(p11;p13) a 1 del(6)(q21)" 2 t(2;7)(p11;p15) 1 del(9)(p22) 4 t(9;12)(p13;p13) a 1 del(6)(q21) 8 t(7;16;?)(p15;p13;?) 1 del(9)(p22) ° 2 tJ(11;12)(p13;p13) 1 del(6)(q21q25) ~ 1 add(7)(q36) 2 del(9)(p22ff b 1 t(12;17)(p13;q21) 1 del(6)(q21q24) 1 dup(7)(q32q36) 1 t(9;12)(p22;q24) 1 t(12;20)(p13;q11) 1 del(6)(q21q23) ~ 1 t(7;12)(q36;q13) 1 del(9)(p21) ~ 4 add(12)(p12) c' 2 del(6)(q21q23) ~ 1 del(14)(q11) 1 del(9)(p21) 1 del(12)(p12) ~' 4 t(6;15)(q21;q21) ~ 1 del(14)(q13) 2 del(9)(p13) ~ 2 t(12;17)(p12;q12) ° 1 t(6;16)(q21;q21) 1 t(3;14)(q25;q11) 1 del(9)(p13) 7 inv(12)(p12p13) 1 del(6)(q22) a 1 t(7;14)(p12;q11) h 1 t(2;9)(q23;p13) ° 1 add(12)(p11) ~ 1 t(6;9)(q23;q12) 1 t(9;14)(p22;q11) 1 t(9;9)(p13;q34) ° 1 del(12)(p11) 2 t(5;6)(q31;q25) 1 t(10;14)(q24;q11) ~'b 4 t(9;17)(p13;q21) 3 inv(12)(p11.2q15) 1 r(6)(p25q27) 1 t(11;14)(p13;q11) °'b 3 del(9)(p12) ° 3 t(1;12)(q21;p11) ~ 1 del(6)(q24q27) 1 t(14;20)(q11;q13) b 1 del(9)(p11) 1 t(2;12)(q31;p11) 1 t(12;14)(p13;q13) 1 add(9)(p11) 1 t(4;12)(q11;p11) 1 t(9;17)(p11;q11) 2 t(12;13)(p11;q11) 1 No. of observations 37 25

t /del(l lq23) No. rea(Ig) No. del(11)(q23) 2 del(2)(p11) 2 del(11)(q23) ~ 1 t(2;12)(p11;p13) 1 del(11)(q13q23) 1 t(2;14)(p11;q11) ~' 1 t(1;11)(p32;q23) 2 add(14)(q32) ° 3 t(1;11)(p22;q23) 1 del(14)(q24q32) 1 t(1;11)(q21;q23) 1 t(5;14)(p11;q32ff b 1 t(2;11)(p11;q23) 1 t(14;17)(q32;q21) 1 t(4;11)(q21;q23) 10 t(14;18)(q32;q21) a 1 t(11;17;19)(q23;q21;q13) 1 del(22)(q11) ° 2 t(11;19)(q23;p13) a 3 del(22)(q13) 1

add(22)(q13) ° 1 dic(21;22)(p11;p11) 1 t(16;22)(p13;q11) 1 t(22;22)(q11;q13) 1

No. of observations 23 18

t(8q24) t(8;14)(q24;q32) t(8;22)(q24;q11) t(8;14)(q24;q11) b

23 23

No. dup(lq) No. 10 dup(1)(q12q25) 1

1 dup(1)(q21q31) ° 2 1 dup(1)(q21q32) 4

dup(1)(q21q42) 2 dup(1)(q23q24) ~' 1 dup(1)(q24q24) 1

12 11

In Figure 10, several different cytogenetic changes observed among the ALL cases are grouped, for logistic reasons. The details of the individual abnormalities grouped together are indicated here.

"Cases in which the abnormality observed was the sole structural change.

t'T-cell ALL. All other cases were precursor B-ALL except for otherwise indicated t(8q24) cases which were B-celt ALL.

rea(TCR) cases involve bands 7p15, 7q36. or 14q11-13. rea(Ig) involve bands 2p11, 14q32, or 22q11-13.

of these abnormali t ies among the 168 cytogenetical ly abnormal cases is not s ign i f ican t ly d i f ferent f rom that r epor t ed by others [1, 7, 31, 52, 54, 55].

The d i s t r ibu t ion of spec i f ic s t ruc tura l c h r o m o s o m e changes w i t h i n FAB subtypes conf i rms p r e v i o u s l y estab- l i shed cy togene t i c -c l in i copa tho log ica l ent i t ies [9]. Trans- loca t ion t(15;17) is c o n f i r m e d as a sens i t ive and spec i f ic marker for M3. Mos t cases of t(8;21) occur in M1 and M2 subtypes , w h i l e mos t cases of i nve r s ion (16) occur in M4 ANLL. Compar i son of f indings in adul t and pedia t r ic ANLL s h o w s imi la r f indings , w i t h the excep t ion of abnormal i t i es resu l t ing in loss of 5q, w h i c h is seen exc lu s ive ly in the adult series. The number of cases in the other cytogenetic subtypes, wh i l e too small for meaningfu l i ndependen t analyses , are neve r the le s s cons i s t en t w i t h p r ev ious ly doc- u m e n t e d cor re la t ions [6-9, 19, 23, 25-31, 56].

An i m p o r t a n t feature of this w o r k is the d o c u m e n t a t i o n of ANLL cases w i t h cy togene t ic f indings sugges t ive of an under ly ing genetic etiology. Several of the changes detai led in Tables 3 and 4 are a m e n a b l e to m o l e c u l a r analyses , and one can reasonab ly predic t , in a n u m b e r of ins tances , at least one cand ida te gene for i n v o l v e m e n t in genet ic re- combina t ions .

ALL

The gains of w h o l e c h r o m o s o m e s in ALL (Figure 6) are c lear ly n o n - r a n d o m , and our f indings con f i rm w o r k f rom several o ther centers [7, 25, 28, 31, 55, 57-59] . Indeed , the cons i s t ency w i t h w h i c h speci f ic c h r o m o s o m e s have been r epor t ed as n o n - r a n d o m l y ga ined is a good ind i ca t i on of a c o m p l e x and impor t an t shared genet ic e t io logy w h i c h r ema ins to be de l inea ted .


"-d

,...1 <

U

U

P~

©

z

m.~ ~ ~ m ~ ~ ~

. ~ ~ ~ ~ ~ ~

C : r ' ~

CXl

E r

~ ,..~ m m ~

~ ~m~"--m~ ~ mm~a ~ m~ ~ --~~__ ~

o ~ .

&s_~Zsl

~ . ~ ~I

co

==..=

o -=~

o ~

~ o

p ~ z t z


The structural changes acquired in our set of ALLs confirm the relat ively high inc idence of rearrangements involving 9p and 12p [60-67]. These bands include, on chromosome 9, the loci of recent ly character ized cyclin- dependent kinase inhibi tor genes which are impl ica ted in the etiology of several neoplasias [68, 69] and, on chromosome 12, TEL--a member of the ETS family of transcription factors [70]. Similarly, rearrangements involving 6q were common in this study, confirming the associat ion of this abnormal i ty wi th l ympho id neoplasias in general [9]. The loci of the T-cell receptor genes and the immunoglobul in heavy and light chain genes were also involved in structural changes in many of the cases in this set, consis tent wi th the wel l -character ized propens i ty of loci in these regions to undergo genetic recombinat ions in l ympho id cells [6, 19]. Abnormal i t ies of 11q23 and 8q24 and dupl ica t ions in l q were conf i rmed as occurr ing at a re la t ive ly high frequency in ALL [1]. Of particular note is the relative rarity of t(1;19) cases among our populat ion. This t ranslocat ion has been repor ted in up to 25% of pre-B ALL [28]. One possible explanat ion for this d iscrepancy could be socio-eco- nomic and geographic factors which may result in differences between the racial background and distr ibution of disease subtypes of our cases compared to those from other centers.

The distribution of specific chromosome rearrangements among ALL subtypes confirms well-established associations [5, 6, 8, 9, 19, 22, 23, 25, 27, 30, 31, 47, 56, 71-73]. Notewor- thy are the associat ions of rearrangements involving 8q24 with a B-cell phenotype, involvement of TCR genes in T-cell cases as wel l as in B-lineage ALL, and preferential involvement of Ig loci in B-lineage ALL. Interestingly, abnormalities of 9p and 12p occurred exclusively in B-lineage cases, whi le 6q de le t ions and t rans loca t ions were seen in both T- and B-lineages. As repor ted by others, 11q23 translocations occurred largely, but not exclusively, in B-lineage ALL. The small number of cases in the remaining cytogenetic subgroups prec ludes making definit ive correlat ions based on this study. However, in the present report, there are no associat ions between cytogenetic abnormali t ies observed and FAB subtypes that are par t icular ly surprising.

The non- random and apparent ly random chromosome changes acquired in our set of ALL cases (Tables 5 and 6) most l ikely inc lude novel genetic muta t ions amenable to character izat ion at the molecular level. Several of the abnormal i t ies documented in Tables 5 and 6 are intr iguing and indeed, in several instances, reports a l ready exist sug- gesting that markers of rare disease subtypes are among the cases documented herein. Future studies of these wil l cont inue to facilitate our unders tanding of the biology of leukemia.

SUMMARY

Over the last two decades, met iculous studies under taken in many cytogenetic laboratories have uncovered most of the major cytogenetic abnormalities non-randomly acquired in leukemias and myelodysplas t ic syndromes. During this time, the d isc ip l ine has progressed from being of uncer- tain cl inical ut i l i ty to having a clearly def ined role in the diagnosis and management of hematological mal ignan-

cies. Our report of cytogenetic studies in 1,143 cases of leukemias and myelodysplas t ic syndromes serves a number of purposes: (1) The data presented confirm many of the wel l -es tabl ished correlat ions be tween acquired cytogenetic changes and morphologica l and immunologica l findings in hematological malignancies. (2) Our data document the findings among an unselected set of consecutive cases tested in a single institution and provide a baseline for further data analyses. (3) Our detailed documentation of novel and apparent ly random changes observed among our s tudy group may assist others in defining rare and as yet uncharacter ized cytogenet ic-c l in icopathological entities. (4) Our s tudy further documents the feasibil i ty of under- taking cancer cytogenetic testing in a regional facili ty per- forming, exclusively, oncological pathology services for several insti tutions. This latter issue is par t icular ly important in the present era of heal th care del ivery cost-contain- ment and ra t ional izat ion of laboratory testing.

The cytogenetic testing done in this study was funded by the Ontario Ministry of Health as a part of a routine diagnostic service. The data collection and analyses presented herein were sup- ported with research funds. The authors wish to acknowledge research support to IDD from the Medical Research Council of Canada, the National Cancer Institute of Canada, and the Hospital for Sick Children Foundation. The technical expertise of Sandy Johnson, Peter Chiang, Debra Derbyshire, Laurie Huang, Earl Stu- art, and Derik Bowman are also acknowledged, as well as the administrative support of Renita Yap.

REFERENCES

1. Helm S, Mitelman F (1995): Cancer Cytogenetics. Chromo- somal and Molecular Genetic Aberrations of Tumor Cells: Wiley-Liss, New York.

2. Haluska FG, Tsujimoto Y, Croce CM (1987): Oncogene activa- tion by chromosomal translocation in human malignancy. Ann Rev Genet 21:321-345.

3. Bloomfield CD, de la Chapelle A (1987): Chromosome abnormalities in acute nonlymphocytic leukemia: Clinical and biological significance. Seminars Oncol 41:372-383.

4. Rowley JD (1990): The Philadelphia chromosome translocation. A paradigm for understanding leukemia. Cancer 65:2178- 2184.

5. Cline MJ (1994): The molecular basis of leukemia. N Engl J Med 330:328-336.

6. Rabbitts TH (1994): Chromosomal translocations in human cancer. Nature 372:143-149.

7. Sandberg AA (1990): The Chromosomes in Human Cancer and Leukemia. 2rid Ed. Elsevier, New York.

8. Rowley JD (1990): Recurring chromosome abnormalities in leukemia and lymphoma. Seminars Hematol 27:122-136.

9. Mitelman F, Helm S (1992): Quantitative acute leukemia cytogenetics. Genes Chromosom Cancer 5:57-66.

10. Dub6 ID, Cournoyer D (1995): Gene therapy: here to stay. Can Med Assoc J 152:1605-1613.

11. Gale RP, Cannani E (1985): The molecular biology of chronic myeloid leukemia. Br J Haematol 60:395-408.

12. Dub6 ID, Carter RF, Pinkerton PH (1990): Chromosome abnormalities in chronic myeloid leukemia. A model for acquired chromosome changes in hematological malignancy. Tumor Biol (Suppl 1) 11:3-24.

Regiona l Cancer Cytogenet ics : A Repor t 79

13. Bennett JM, Catovsky D, Daniel M-T, Flandrin G, Galton DAG, Gralnick HR, Sultan C (1976): Proposals for the classifi- cation of the acute leukemias. Br J Haematol 33:451-458.

14. ISCN (1995): An International System for Human Cytoge- netic Nomenclature. Mitelman F (ed). S Karger, New York.

15. Dub6 ID, Dixon J, Beckett T, Grossman A, Weinstein M, Benn P, McKeithan T, Norman C, Pinkerton P (1989): Location of breakpoints within the major breakpoint cluster region (bcr) in 33 patients with bcr rearrangement-positive chronic myeloid leukemia (CML) with complex or absent Philadelphia chromosomes. Genes Chromosom Cancer 1:106-111.

16. Noel P, Tefferi A, Pierre RV, Jenkins RB, Dewald GW (1993): Karyotypic analysis in primary myelodysplastic syndromes. Blood Rev 7:10-18.

17. Nowell PC (1992): Chromosome abnormalities in mye]odys- plastic syndromes. Seminars Oncol 19:25-33.

18. Hunger SP, Cleary ML (1993): Chimaeric oncoproteins resulting from chromosomal translocations in acute lymphoblastic leukemia. Seminars Cancer Biol 4:387-399.

19. Drexler HG, MacLeod RFA, Borkhardt A, Janssen JWG (1995): Recurrent chromosomal translocations and fusion genes in leukemia-lymphoma cell lines. Leukemia 9:480-500.

20. Dub6 ID, Kamel-Reid S, Yuan CC, Lu M, Wu X, Corpus G, Raimondi SC, Crist WM, Carrol AJ, Minowada J, Baker JB (1991): A novel human homeobox gene lies at the chromosome 10 breakpoint in lymphoid neoplasias with chromosomal translocation t(10;14)(q24;q11). Blood 78:2996-3003.

21. Dub6 ID, Greenberg ML (1986): Phenotypic heterogeneity in three cases of lymphoid malignancy with chromosomal translocations 14q11. Cancer Cytogenet Cell Genet 41:215-218.

22. Pui CH, Crist WM, Look AT (1990): Biology and clinical significance of cytogenetic abnormalities in childhood acute lymphoblastic leukemia. Blood 76:1449-1463.

23. Heerema N (1990): Cytogenetic abnormalities and molecular markers of acute lymphoblastic leukemia. Hematol Oncol Clinics North Am 4:795-820.

24. Suciu S, Kuse R, Weh HJ, Hossfeld DK (1990): Results of chromosome studies and their relation to morphology, course, and prognosis in 120 patients with de novo myelodysplastic syndrome. Cancer Genet Cytogenet 44:15-26.

25. Rubin CM, LeBeau MM, Mick R, Bitter MA, Nachman J, Rudinsky R, Appel HJ, Morgan E, Suarez CR, Schumacher HR, Subramanian U, Rowley J (1991): Impact of chromosomal translocations on prognosis in childhood acute lymphoblastic leukemia. J Clinical Oncology 9:2183-2192.

26. van der Plas D, H~ihlen K, Hagemeijer A (1992): Prognostic significance of karyotype at diagnosis in childhood acute lymphoblastic leukemia. Leukemia 6:176-184.

27. Groupe Fran~ais de Cytog6n6tique H6matologique (1993): Collaborative study of karyotypes in childhood acute lymphoblastic leukemia. Leukemia 7:10-19.

28. Raimondi SC (1993): Current status of cytogenetic research in childhood acute lymphoblastic leukemia. Blood 81:2237-2251.

29. Stasi R, del Poeta G, Masi M, Tribalto M, Venditti A, Papa G, Nicoletti B, Vernole P, Tedeschi B, Delaroche I, Mingarelli R, Dallapiccola B (1993): Incidence of chromosome abnormalities and clinical significance of karyotype in de novo acute myeloid leukemia. Cancer Genet Cytogenet 67:28-34.

30. Copelan EA, McGuire EA (1995):°The biology and treatment of acute lymphoblastic leukemia in adults. Blood 85:1151-1168.

31. Helm S, Mitelman F (1992): Cytogenetic analysis in the diagnosis of acute leukemia. Cancer (Suppl) 70:1701-1709.

32. Second International Workshop on Chromosomes in Leuke- mia. Chromosomes in preleukemia (1980): Cancer Genet Cytogenet 2:108-113.

33. Knapp RH, Dewald GW, Pierre RV (1985): Cytogeuetic studies

in 174 consecutive patients with preleukemic or myelodysplastic syndromes. Mayo Clinic Proc 60:507-516.

34. Tricot G, Vlietinck R, Boogaerts MA, Hendricks B, de Wolf- Peeters C, van den Berghe H, Verwilghen RL (1985): Prognos- tic factors in the myelodysplastic syndromes: Importance of initial data on peripheral blood counts, bone marrow cytol- ogy, trephine biopsy and chromosomal analysis. Br J Haema- tol 60:19-32.

35. Jacobs RH, Cornbleet MA, Vardiman JW, Larson RA, Le Beau MM, Rowley JD (1986): Prognostic implications of morphology and karyotype in primary myelodysplastic syndromes. Blood 67:1765-1772.

36. Horiike S, Taniwaki M, Misawa S, Abe T (1988): Chromo- some abnormalities and karyotype evolution in 83 patients with myelodysplastic syndrome and predictive value for prognosis. Cancer 62:1129-1138,

37. Yunis JJ, Lobell M, Arnesen MA, Oken MM, Mayer MG, Rydell RE, Brunning RD (1988): Refined chromosome study helps define prognostic subgroups in most patients with primary myelodysplastic syndrome and acute myelogenous leukemia. Br J Hematol 68:189-194.

38. Fourth International Workshop on Chromosomes in Leuke- mia (1984): A prospective study of acute nonlymphocytic leukemia. Cancer Genet Cytogenet 11:249-360.

39. Prigogina EL, Fleischman EW, Puchkova GP, Mayakova SA, Volkova MA, Protasova AK, Frenkel MA (1986): Chromosomes in acute nonlymphocytic leukemia. Hum Genet 73:137-146.

40. Berger R, Flandrin G, Berhheim A, Le Coniat M, Vecchione D, Pacot A, Derr6 J, Daniel M-T, Valensi F, Sigaux F, Ochoa- Noguera ME (1987): Cytogenetic studies on 519 consecutive de novo acute nonlymphocytic leukemias. Cancer Genet Cytogenet 29:9-21.

41. Keating MJ, Smith TL, Kantarjian H, Cork A, Walters R, Trujillo JM, McCredie KB, Gehan EA, Freireich EJ (1988): Cytogenetic pattern in acute myelogenous leukemia: A major reproducible determinant of outcome. Leukemia 2:403-412.

42. Misawa S, Yashige H, Horiike S, Taniwaki M, Nishigaki H, Okuda T, Yokota S, Tsuda S, Edagawa J, Imanishi H, Takino T, Inazawa J, Maekawa T, Fujii H, Akaogi T, Hayashi H, Fujiyama Y, Kohasaki M (1988): Detection of karyotypic abnormalities in most patients with acute nonlymphocytic leukemia by adding ethidium bromide to short-term cultures. Leukemia Res 12:719-729.

43. Schiffer CA, Lee EJ, Tomiyasu T, Wiernik PH, Testa JR (1989): Prognostic impact of cytogenetic abnormalities in patients with de novo acute non-lymphocytic leukemia. Blood 73:263-270.

44. Kalwinsky DK, Raimondi SC, Schell MJ, Mirro Jr J, Santana VM, Behm F, Dahl GV, Williams D (1990): Prognostic importance of cytogenetic subgroups in de novo pediatric nonlymphocytic leukemia. J Clin Oncol 8:75-83.

45. Marosi C, K611er U, Koller-Weber E, Schwarziner I, Schneider B, J~ger U, Vahls P, Nowotny H, Pirc-Danoewinata H, Steger G, Kreiner G, Wagner B, Lechner K, Lutz D, Bettelheim P, Haas OA (1992): Prognostic impact of karyotype and immunologic phenotype in 125 adult patients with de novo AML. Cancer Genet Cytogenet 61:14-25.

46. Third International Workshop on Chromosomes in Leukemia (1981): Chromosomal abnormalities in acute lymphoblastic leukemia. Cancer Genet Cytogenet 4:101-110.

47. Williams DL, Harber J, Murphy SB, Look AT, Kalwinsky DK, Rivera G, Melvin SL, Stass S, Dahl GV (1986): Chromosomal translocations play a unique role in influencing prognosis in childhood acute lymphoblastic leukemia. Blood 68:205-212.

48. Heinonen K, Rautonen J, Slimes MA, Knuutila S (1988): Cytogenetic study of 105 children with acute lymphoblastic leukemia. Eur J Haematol 41:237-242.

49. Prigogina EL, Puchkova GP, Mayakova SA (1988): Non-ran-


dom chromosomal abnormalities in acute lymphoblastic leukemia of childhood. Cancer Genet Cytogenet 32:183-203.

50. Helm S, B6k~ssy AN, Garwicz S, Heldrup J, Kristofferson U, Mandahl N, Wiebe T, Mitelman F (1990): Bone marrow karyotypes in 94 children with acute leukemia. Eur J Hematol 44:227-233.

51. Katz JS, Taylor LD, Carroll A, Elder FFB, Mahoney DH (1991): Cytogenetic features of childhood acute lymphoblastic leukemia. A concordance study and a Pediatric Oncology Group study. Cancer Genet Cytogenet 55:249-256.

52. Mitelman F (1994): Catalog of Chromosome Aberrations in Cancer. 5th Ed. Wiley-Liss, New York.

53. Pierre RV, Catovsky D, Mufti GJ, Swansbury GJ, Mecucci C, Dewald GW, Ruutu T, van den Berghe H, Rowley JD, Mitel- man F, Reeves BR, Alimena G, Garson OM, Lawler SD, de la Chapelle A (1989): Clinical-cytogenetic correlations in myelo- dysplasia (preleukemia). Cancer Genet Cytogenet 40:149-161.

54. Machnicki JL, Bloomfield CD (1990): Chromosomal abnormalities in myelodysplastic syndromes and acute myeloid leukemia. Clin Lab Med 10:755-767.

55. Helm S (1990): Cytogenetics in the investigation of haemato- logical disorders. Balliere's Clin Hematol 3:921-948.

56. Pui C-H (1995): Childhood Leukemias. New Engl J Med 332:1618-1630.

57. Secker-Walker LM (1990): Prognostic and biological importance of chromosome findings in acute lymphoblastic leukemia. Cancer Genet Cytogenet 49:1-13.

58. Berger R (1991): Molecular cytogenetics of acute lymphoblastic leukemia. Nouv Rev Fr Hematol 33:86-91.

59. Kaneko Y (1991): Chromosome abnormalities, clinical features, and molecular mechanisms in leukemia. Acta Pathol Jpn 41:713-721.

60. Chilcote RR, Brown E, Rowley JD (1985): Lymphoblastic leukemia with lymphomatous features associated with abnormalities of the short arm of chromosome 9. N Engl J Med 313:286-291.

61. Raimondi SC, Williams DL, Callihan T, Peiper S, Rivera GK, Murphy SB (1986): Nonrandom involvement of 12p12 breakpoint in chromosome abnormalities of childhood acute lymphoblastic leukemia. Blood 68:69-75.

62. Smith SD, Link MP, Rtela M, Amylon M, Sklar J, Morgan R, Hecht F (1986): Chromosome 9 abnormalities in childhood T-cell leukemia. N Engl J Med 315:195-196.

63. Pollak C, Hagemeijer A (1987): Abnormalities of the short arm of chromosome 9 with partial loss of material in hematological disorders. Leukemia 1:541-548.

64. Murphy SB, Raimondi SC, Rivera GK, Crone M, Dodge RK, Behm FG, Pui C-H, Williams DL (1989): Nonrandom abhor-

realities of chromosome 9 in childhood acute lymphoblastic leukemia: Association with high-risk clinical features. Blood 74:409-415.

65. Kobayashi H, Montgomery KT, Bohlander SK, Adra CN, Lira BL, Kucherlapati RS, Donis-Keller H, Holt MS, Le Beau MM, Rowley JD (1994): Fluorescence in situ hybridization mapping of translocations and deletions involving the short arm of human chromosome 12 in malignant hematologic dis- eases. Blood 84:3473-3482.

66. Kobayashi H, Rowley JD (1995): Identification of cytogenetically undetected 12p13 translocations and associated deletions with fluorescence in situ hybridization. Genes Chromosom Can- cer 12:66-49.

67. Dreyling MH, Bohlander SK, LeBeau MM, Olopade OI (1995): Refined mapping of genomic rearrangements involving the short arm of chromosome 9 in acute lymphoblastic leukemias and other hematologic malignancies. Blood 86:1931- 1938.

68. Otsuki T, Clark HM, Wellmann A, Jaffe ES, Raffeld M (1995): Involvement of CDKN2 (p16ink41/MTS1) and pI5INK4B/ MTS2 in human leukemias and lymphomas. Cancer Res 55:1436-1440.

69. Okuda T, Shurtleff SA, Valentine MB, Raimondi SC, Head DR, Behm F, Curcio-Brint AM, Liu W, Pui C-H, Sheer CJ, Beach D, Look AT, Downing JR (1995): Frequent deletion of p16INK4a/MTS1 and p15INK4b/MTS2 in pediatric acute lymphoblastic leukemia. Blood 85:2321-2330.

70. Stegmaier K, Pendse S, Barker GF, Bray-Ward P, Ward DC, Montgomery KT, Krauter KS, Reynolds C, Sklar J, Donnelly M, Bohlander SK, Rowley JD, Sallan SE, Gilliland DG, Golub TR (1995): Frequent loss of heterozygosity at the TEL gene locus in acute lymphoblastic leukemia of childhood. Blood 86:38-44.

71. Williams DL, Look AT, Melvin SL, Roberson PK, Dahl G, Flake T, Stass S (1984): New chromosomal translocations correlate with specific immunophenotypes of childhood acute lymphoblastic leukemia. Cell 36:101-109.

72. Bloomfield CD, Goldman AI, Alimena G, Berger R, BorgstrSm GH, Brandt L, Catovsky D, de la Chapelle A, Dewald GW, Gar- son OM, Garwicz S, Golomb HM, Hossfeld DK, Lawlwer SD, Mitelman F, Milsson P, Pierre RV, Philip P, Prigogina E, Row- ley JD, Sakurai M, Sandberg AA, Secker-Walker LM, Tricot G, van den Berghe H, van Orshoven A, Vuopio P, Whang-Peng J (1986): Chromosomal abnormalities identify high-risk and low-risk patients with acute lymphoblastic leukemia. Blood 67:415-420.

73. Uckun FM, Gajl-Peczalska KJ, Provisor AJ, Heerema NA (1989): Immunophenotype-karyotype associations in human acute lymphoblastic leukemia. Blood 73:271-280.

Regional cancer cytogenetics: A report on 1,143 diagnostic cases

Documents

Transcript of Regional cancer cytogenetics: A report on 1,143 diagnostic cases