Gabriele Minuti

Medical Oncology DivisionCivil Hospital of Livorno

MET as a biomarker for target therapies

MET as a biomarker for target therapies

MET and its ligand HGF regulate multiple cellular processes that stimulate cell proliferation, invasion/metastasis and angiogenesis.

MET/HGF signaling pathway represents a relevant target for personalized cancer treatment based on high frequency of MET and/or HGF overexpression, activation and amplification.

Aberrant MET activation occurs in different kind of tumor such as non small cell lung cancer, gastro-esophageal cancer, ovarian cancer, breast cancer, kidney cancer, thyroid cancer, liver cancer and gliomas.

The key role that MET plays in malignant transformation suggests that inhibition of MET signaling may abrogate growth and progression of cancers in which its activity is increased.

MET and HGF INHIBITORS

INHIBITORS of HGF ACTIVATORS and HGF

MET ANTAGONISTS

MET KINASE INHIBITORS

MET/HGF INHIBITORS ONGOING TRIALS

MET and HGF in BREAST CANCER

MET and HGF overexpression correlates with short relapse-free and overall survival.

Raghav et al. reported that high levels of MET protein expression was associated with poor prognosis in early breast cancer.

Functional crosstalk of MET with EGFR, ERBB2 or insulin-like growth factor 1 receptor (IGF1R) has been reported in several systems and has emerged as a major mechanism for cancer progression and resistance to therapy.

Lindemann et al. reported MET overexpression in 25% of HER2-positive breast tumors, supporting the hypothesis that both HER2 and MET receptors could synergize in promoting tumor growth.

Shattuck et al. showed that MET contributes to trastuzumab resistance, and a subset of HER2-positive breast cancer patients may benefit from combined inhibition of both HER2 and MET.

MET and HGF in BREAST CANCER

Aim of the study: to investigate whether copy number gain of MET or its ligand HGF affect trastuzumab sensitivity in HER2+ MBC patients.

130 HER2+ MBC treated with trastuzumab as single agent or in combination with chemotherapy.

MET and HGF gene copy numbers (GCN) were assessed by FISH in primary breast cancer samples.

MET FISH analysis was successfully performed in all 130 cases. HGF FISH analysis was performed in 84 cases (64.6%).

MET and HGF in BREAST CANCER

ROC analysis was applied to find the best cut-off point for both MET and HGF GCN discriminating between sensitive (CR+PR+SD) and refractory (PD at the first imaging assessment) patients.

Specificity

1,0,8,5,30,0

Sen

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1,0

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Specificity

1,0,8,5,30,0

Sen

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1,0

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0,0

AUC=0.679 AUC=0.663

MET ROC analysis HGF ROC analysis

MET CUT-OFF : 3.72 mean GCN HGF CUT-OFF : 3.01 mean GCN

Failure Rate (%) TTP (months) OS (months)

MET FISH + (N=36, mean≥3.72) 44.4% 5.7 26.4

MET FISH - (N=94, mean<3.72) 16.0% 9.9 29.1

P-value0.001 0.006 0.681

Time To Progression (months)

706050403020100

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Survival time (months)

140120100806040200

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MET FISH positive Vs negative

P=0.006;HR 1.74 (95% CI 1.16-2.62) P=0.681;HR 1.12 (95% CI 0.65-1.93)

MET FISH -N=83

MET FISH + N=34

MET FISH + N=17

MET FISH -N=55

Failure Rate (%) TTP (months) OS (months)

HGF FISH + (N=33, mean ≥3.01) 30.3% 9.9 35.2

HGF FISH - (N=51, mean<3.01) 7.8% 10.5 26.1

P-value0.007 0.665 0.567

Survival time (months)

140120100806040200

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1,0

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HGF FISH positive Vs negative

P=0.006;HR 1.74 (95% CI 1.16-2.62) P=0.681;HR 1.12 (95% CI 0.65-1.93)

MET FISH -N=83

MET FISH + N=34

MET FISH + N=17

MET FISH -N=55

Time To Progression (months)

6050403020100

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1,0

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Survival time (months)

140120100806040200

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1,0

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P=0.665 ; HR 1.10 (95% CI 0.70-1.74) P=0.567; HR 0.83 (95% CI 0.44-1.56)

HGF FISH -N=48

HGF FISH +N=31

HGF FISH + N=14

HGF FISH -N=31

MET/HGF FISH combination

Results confirmed that failure rate was significantly lower in the population negative for both MET and HGF (P=0.007), with a percentage of progressing patients not significantly different than that detected with a single biomarker assay .

Outcome according to MET and HGF GCN in 84 patients evaluable for both biomarkers

MET and HGF in BREAST CANCER Response to trastuzumab therapy as well as TTP were significantly better in patients with no MET GCN gain, supporting the potential therapeutic impact of anti-MET agents in MBC, particularly in combination with anti-HER2 agents.

A combination of anti-MET and anti-HER-targeted agents should be tested as a treatment option in HER2-positive patients with MET-overexpressing tumors.

We find a strong association of MET and HGF GCN. The presence of increased GCN of both MET and HGF in the same tumors could explain why a single test was equally predictive than the combination of both assays.

Ligand-dependent MET activation could represent the predominant mechanism in HER2-positive breast cancer, indicating a potential role for anti-MET monoclonal antibodies in breast cancer.

G. MINUTI et al. SUBMITTED

CONCLUSIONS

The role of HGF/MET aberrant signalling in cancer is clear, and effective therapeutics are now available.

Methods for assessing the level of HGF/MET expression and activity have not been extensively validated and deployed.

Patient stratification according to HGF/MET expression or MET phosphorylation needs further development and is not currently an important component of study design in the numerous clinical trials that are in progress.

Patient stratification is an essential component for therapeutic success and suggest that analysis of HGF/MET expression levels and/or receptor phosphorylation may constitute valid strategies.

I would like to thank…

F. Cappuzzo, R. Duchnowska, J. Jassem, A. Fabi, T. O’Brien, A. D. Mendoza, L. Landi, W. Biernat, B. Czartoryska-Arłukowicz, T. Jankowski, D. Zuziak, J. Zok, B. Szostakiewicz, M. Foszczyńska-Kłoda, A. Tempińska-Szałach, E. Rossi, A. Destro, M. Roncalli , M. Varella-GarciaDepartment of Medical Oncology, Civil Hospital of Livorno/Istituto Toscano Tumori, Livorno, Italy Military Institute of Medicine, Warsaw, Poland Medical University of Gdańsk, Gdańsk, PolandNational Cancer Institute Regina Elena, Rome, ItalyLaboratory of Molecular Pathology, University of Colorado Cancer Center, Aurora, Colorado, USA Białystock Oncology Center, Białystock, Poland Lublin Oncology Center, Lublin, PolandBeskidy Oncology Center, Bielsko-Biała, PolandWarmia and Masuria Oncology Center, Olsztyn, Poland West Pomeranian Oncology Center, Szczecin, PolandDistrict Hospital of Elbląg, Elbląg, PolandMilan University, Istituto Clinico Humanitas, Milan, Italy