Inhibition of c-MET is a potential therapeutic strategy for treatment of diffuse large B-cell lymphoma

Hepatocyte growth factor/c-MET has emerged as a potential therapeutic target for several cancers; however, its role in diffuse large B-cell lymphoma (DLBCL) has not been fully elucidated. In this study, we first investigated the role of c-Met in a large series of DLBCL tissues in a tissue microarray format. We then followed this with in vitro studies on DLBCL cell lines using either pharmacological inhibitors of c-Met or siRNA knockdown strategy. c-Met was found to be overexpressed in 73.2% of patients (186/254) and was significantly associated with overexpression of p-AKT (P = 0.0274), p-GSK3 (P = 0.0047) and Ki-67 (P = 0.0012). Interestingly, c-Met overexpression was significantly more common in the germinal center subtype of DLBCL, as compared with activated B cell subtype (P = 0.0002). Overexpression of c-Met in DLBCL was significantly associated with better survival (P = 0.0028) and remained significant in multivariate analysis with international prognostic index, thereby confirming c-Met as independent prognostic marker for better outcome in DLBCL. In vitro pharmacological c-Met inhibition and siRNA targeted against c-Met triggered caspase-dependent apoptosis. These findings provide evidence that c-Met is an independent prognostic marker for better outcome in Middle Eastern DLBCL. This data also enlightens the fact that c-Met through AKT kinase has a critical role in carcinogenesis of DLBCL, and strongly suggest that targeting c-Met may have therapeutic value in treatment of DLBCL. Laboratory Investigation (2010) 90, 1346-1356; doi:10.1038/labinvest.2010.108; published online 7 June 2010