EXPRESSION OF C-MET IN LARYNGEAL CARCINOMA

Expression of c-Met, a gene for the hepatocyte growth factor/scatter f actor (HGF/SF) receptor, is known to be associated with tumour develop ment in several human carcinomas. The expression of c-Met was examined using immunohistochemistry in 82 cases of primary laryngeal carcinoma to evaluate the tissue distribution of c-Met and the clinicopathologi cal significance of c-Mer expression. In normal larynx, c-Met expressi on was observed only in some minor salivary glands. Positive reaction for c-Met in neoplastic epithelium was noted in 45 out of 82 (54.9%) c ases. In 44 cases, structures adjacent to the carcinoma (noncancerous squamous epithelium, some stromal fibroblastic cells, and endothelial cells) showed positive reaction for c-Met. c-Met expression in cancero us epithelium was significantly correlated with lymph node status (P<0 .04) and proliferating activity expressed by the Ki-67 labelling index (P<0.02). There was no correlation between c-Met expression and age, sex, histological type, T category, distant metastasis or clinical sta ge. The data suggest that overexpression of c-Mer in laryngeal carcino mas represents a growth advantage for cancer cells, which may be confe rred by the mitogenic effect of HGF/SF Simultaneous c-Met expression i n noncancerous components of the larynx may represent present a paracr ine modification of c-Met.