Prognostic Value and Clinical Pathology of c-MET Expression and Amplification in Gastric Carcinoma

The MET oncogene encodes the receptor tyrosine kinase (RTK) for hepatocyte growth factor (HGF) and controls genetic programs leading to cell growth, invasion and protec¬tion from apoptosis. Although the definitive role of MET oncogene is yet to be determined in carcinogenesis of gastric cancer, overexpression and amplification of c-Met has been demonstrated in gastric cancer cell lines. In addition, approximately 10-20% of gastric cancer tissues and up to 40% of the scirrhous histological subtype were shown to harbor increased MET gene copy numbers. Importantly, PHA-665,752, a selective c-Met kinase inhibitor showed significant reduction of established tumor mass in mouse xenografts with GTL16, a gastric cancer cell line with \>10-fold MET amplification. Another pivotal study showed that gastric cancer cells with MET amplification were extremely sensitive to PHA-665,752 and implicated a potential role of c-Met protein in developing theranostics in gastric cancer. More and more data indicated that c-Met was an important prognostic factor in gastric cancer. Gastric cancer is a heterogeneous disease. Does the expression and amplification of c-Met in the primary lesion differ from the metastatic disease? Does the expression and amplification of c-Met in the early disease differ from advanced disease? Till now there is no related report. Purposes: * Compare the expression and amplification of c-Met between primary lesion and metastatic lesion together with clinical characteristic, to explore the relationship of c-Met expression and metastatic pattern * Compare the expression and amplification of c-Met between early stage and metastatic stage, and to explore the role of c-MET in the development of carcinoma