PROTOONCOGENE PRODUCT, pp 60^c-src ACTIVATION IN HEPATOCELLULAR CARCINOMA

A COMPARATIVE STUDY IN TUMOROUS AND ADJACENT NONTUMOROUS PORTIONS OF HEPATOCELLULAR CARCINOMA

Abstract

Nine src family members are known to date: c-src, c-yes, c-lck, c-fyn, c-hck, c-lyn, c-blk, c-fgr and c-yrk. They encode proteins of molecular weights of 55 to 62 kilodaltons, which are non-receptor type, membrane associated and protein tyrosine kinases. For the related Src kinases, a close correlation exists between elevated tyrosine kinase activity and cell transformation. However, the involvement of pp 60^c-src in human hepatocellular carcinoma remains obscure. In this study, we analyzed the amount of pp 60^c-src at protein and/or kinase activity levels in tumorous and adjacent nontumorous portions of hepatocellular carcinoma from the same patient. The kinase activity of pp 60^c-src was significantly elevated in the tumorous tissue, than in the nonmtumorous cirrhotic portions. These results suggest that activation of the protooncogene product pp 60^c-src may play an important role in the malignant transformation of hepatocytes in human liver.