The unique protein kinase Cη: Implications for breast cancer (Review)

Deregulation of key signal transduction pathways that govern important cellular processes leads to cancer. The development of effective therapeutics for cancer warrants a comprehensive understanding of the signaling pathways that are deregulated in cancer. The protein kinase C (PKC) family has served as an attractive target for cancer therapy for decades owing to its crucial roles in several cellular processes. PKC eta is a novel member of the PKC family that plays critical roles in various cellular processes such as growth, proliferation, differentiation and cell death. The regulation of PKC eta appears to be unique compared to other PKC isozymes, and there are conflicting reports regarding its role in cancer. This review focuses on the unique aspects of PKC eta in terms of its structure, regulation and subcellular distribution and speculates on how these features could account for its distinct functions. We have also discussed the functional implications of PKC eta in cancer with particular emphasis on breast cancer.