Expression of HGF/SF and Met protein is associated with genetic alterations of VHL gene in primary renal cell carcinomas

We analyzed the genetic alterations of VHL, HGF/SF, and Met genes and the expression pattern of HGF/SF and Met protein in 26 renal cell carcinomas (RCCs). We found five mutations of the VHL gene and frequent LOH (50%) only in non-papillary clear cell RCC. We found six cases in which the CpG island of VHL was methylated. In addition, one missense mutation of the HGF/SF gene was detected in clear cell RCC. HGF/SF and Met protein were expressed in 84.6% and 80.7% of RCCs, respectively. All of the cases with the genetic alterations of VHL or HGF/SF demonstrated strong expression of HGF/SF and Met protein in RCC cells. Statistically, genetic alterations of VHL and HGF/SF were significantly correlated with HGF/SF and Met expression (Fisher's exact test, p=0.022 and P=0.0070). Thus, these results strongly suggest that the expression of HGF/SF and Met protein is closely associated with the genetic alterations of VHL and HGF/SF in primary RCCs.