Protein kinase C(PKC) is the main signaling molecule of the diacylglycerol dependent protein kinase C signal transducting system.PKC plays an important role in the generation and progress of cancer.The activation of PKC is associated with the proliferation,differentiation,apoptosis,migration and multidrug resistance(MDR) of tumor cells.It may become a novel anti-tumor strategy to block the proliferation and drug resistance signal transduction passageways with new specific PKC inhibitors directed at the PKC subgroup in tumor cells.