c-Met is an attractive target for gastric cancer (GC) therapy, and detection of c-Met expression is critical for diagnosis. The aims of this study were to quantify the heterogeneous expression of c-Met in GC and to explore its impact on diagnosis. The expression of c-Met in 199 tumor fragments derived from 47 GC patients was evaluated by immunohistochemistry. In parallel, copy numbers of MET were determined by fluorescence in situ hybridization. Expression of c-Met was observed in 22 patients, and 18 (81.8%) of 22 were heterogeneous; but the incidence rate of heterogeneity was not significantly different among patient subgroups with various degrees of c-Met expression. MET copies were increased in 4 patients. Two represented polysomy, and 2 were caused by amplification. Expression of c-Met in MET-amplified tumors was homogeneous. In conclusion, heterogeneity of c-Met expression was widely observed in GC but was not associated with the extent of expression.
Keywords: Amplification; Gastric cancer; Heterogeneity; Homogeneity; Overexpression; c-Met.
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