Abstract B31: Biomarker selection defines a subgroup of hepatocellular carcinoma (HCC) patients with poor prognosis who are candidates for MET inhibition strategy.

Abstract

Abstract Background: Acquired resistance to VEGFR/PDGFR inhibitors has been associated with various aspects of epithelial-to-mesenchymal transition. c-MET/HGF, TGF-beta, and CXCR4/CXCL12 are among the main pathways triggered by antiangiogenic therapies, facilitating cellular invasion and occurrence of metastases. The most advanced MET pathway inhibitors are currently under phase 3 clinical evaluation. In addition, initial data suggest that carbonic anhydrase 9 (CA9) is associated with HCC development. The aim of this study was to correlate c-MET and CA9 expression levels by immunochemistry with clinicopathologic characteristics and disease-free survival (DFS) in patients with HCC. Materials and Methods: One-hundred formalin-fixed and paraffin-embedded HCC resection specimens from 100 patients were evaluated by immunohistochemistry using the Ventana platform (anti-c-MET clone Sp44 and a polyclonal CA9). Staining results were qualitatively and quantitatively assessed (using both manual and automated evaluation) and correlated with clinical and serologic parameters. Based on previously published automated quantitative assessment of c-MET staining (Garcia S, 2007), we elaborated our own dedicated macro, using ImageJ software. High c-MET expression was defined as moderate to strong staining (2+ and 3+ on a 0-3+ scale). Univariate analyses were performed using Fisher's exact or chi square test, and multivariate analyses using Cox regression model. Median DFS was calculated by Kaplan-Meier method. Results: Ninety-seven evaluable samples were included in the data analysis. Patients were mainly males (84%). Tumors were classified as BCLC A1 (92%), uninodular (53%), low-AFP-expressing (81%), moderately differentiated (60%), and with portal invasion (70%). c-MET staining was cytoplasmic and membranous. High c-MET expression was observed in 51% of tumors. c-MET expression level was higher in patients with viral hepatitis-associated HCC (p=0.02) and in patients with AFP>400UI/L (p=0.03). High CA9 expression was observed in 41% of tumors and was correlated with viral hepatitis (p=0.002), pathological portal vein invasion (p=0.007), and poor differentiation (p=0.007). c-MET and CA9 expression levels significantly correlated with each other (p=0.008). Median DFS was shorter in the high-c-MET (12.9 months, vs >80 months in low-c-MET; p=0.018) and high-CA9 (10.2 months, vs 34.4 months in low-CA9; p=0.02) populations. Comparison of c-MET and CA9 status discriminated 4 groups with distinct prognosis: in the c-MET-high/CA9-high group the shortest median DFS was 10.7 months, whereas this was not reached in the c-MET-low/CA9-low group (p=0.003). c-MET-high/CA9-low and c-MET-low/CA9-high groups were defined as intermediate risk populations. Multivariate analysis showed that tumor size (p=0.025), morphology (uni- vs multinodular; p=0.004), and CA9 expression level (p=0.007) were independently associated with DFS; c-MET expression level was significantly associated with DFS when CA9 was excluded from the model (p=0.024). Conclusion: c-MET expression is a useful prognostic marker in HCC that could be used for patient stratification. HCC overexpressing c-MET and CA9 represents a subgroup of patients with a particularly poor prognosis who might benefit from therapy with c-MET inhibitors. Citation Information: Mol Cancer Ther 2013;12(11 Suppl):B31. Citation Format: Annemilai Tijeras-Raballand, Miguel Albuquerque, Cindy Neuzillet, Nathalie Colnot, Friedhelm Badt, Christian Ihling, Manfred Klevesath, Hongxia Zheng, Eric Raymond, Armand de Gramont, Sandrine Faivre, Valérie Paradis. Biomarker selection defines a subgroup of hepatocellular carcinoma (HCC) patients with poor prognosis who are candidates for MET inhibition strategy. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2013 Oct 19-23; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2013;12(11 Suppl):Abstract nr B31.