The Roles of Specific Isoforms of Protein Kinase C (PKC) in Signal Transduction, Growth Control and Diacylglycerol Metabolism

The conversion of normal cells to tumor cells is a highly complex process since it involves multiple steps, multiple factors (both exogenous and endogenous) and multiple genes. In the field of chemical carcinogenesis this process can often be divided into three major stages: initiation, which is generally triggered by DNA damage; promotion, which is induced by agents that do not directly damage DNA but enhance cell growth and alter gene expression; and progression, the conversion of benign tumors to malignant lesions. The latter stage is also enhanced by genotoxic agents and involves multiple genetic changes (Weinstein, 1988; Weinstein et al, 1991; Weinstein, 1991).