c-MET Overexpression in Colorectal Cancer: A Poor Prognostic Factor for Survival

Mesenchymal-epithelial transition factor gene (c-MET) overexpression might be an important biomarker in colorectal cancer (CRC). We evaluated the incidence of c-MET overexpression and its prognostic significance in 255 patients with metastatic CRC. We found that 15.3% had c-MET overexpression and c-MET overexpression was associated with shorter survival. Introduction: Increased mesenchymal-epithelial transition factor gene (c-MET) expression in several human malignancies is related to increased tumor progression and is a new potential drug target for several types of cancers. In the present study, we investigated the incidence of c-MET overexpression and its prognostic significance in patients with colorectal cancer (CRC). Patients and Methods: We retrospectively reviewed the data from 255 stage IV CRC patients who had results from a c-MET immunohistochemical test at Samsung Medical Center. We explored the relationships between c-MET overexpression and clinicopathological features and survival. Results: Primary tumor sites were 67 right-sided colon, 98 left-sided colon, and 90 rectum. Forty-two patients (16.7%) had poorly differentiated or mucinous carcinoma. Among the 255 patients, 39 (15.3%) exhibited c-MET overexpression. There was no significant difference in the prevalence of c-MET overexpression according to primary site, histologic differentiation, molecular markers, or metastatic sites. In a comparison of the tumor response to first-line chemotherapy according to the level of c-MET expression, we found no significant difference in either partial response or disease control rate. In the survival analysis, patients with c-MET overexpression had significantly shorter overall survival (39 vs. 27 months; P =.018) and progression-free survival (PFS) during bevacizumab treatment (10 vs. 7 months; P =.024). Conclusion: c-MET overexpression, which was detected in 39 CRC patients (15.3%) irrespective of primary sites or molecular markers, indicated a poor survival prognosis and predicted shorter PFS during bevacizumab treatment in patients with CRC. Further studies are warranted to elucidate the value of c–MET-targeted therapy in CRC patients.