Multiple functions of p27(Kip1) and its alterations in tumor cells: A review

Cyclin-dependent kinases (CDKs), together with cyclins, their regulatory su bunits, govern cell-cycle progression in eukaryotic cells. p27(Kip1) is a m ember of a family of CDK inhibitors (CDIs) that bind to cyclin/CDK complexe s and arrest cell division. There is considerable evidence that p27(Kip1) p lays an important role in multiple fundamental cellular processes, includin g cell proliferation, cell differentiation, and apoptosis. Moreover, p27(Ki p1) is a putative tumor-suppressor gene that appears to play a critical rol e in the pathogenesis of several human malignancies and its reduced express ion has been shown to correlate with poor prognosis in cancer patients. Thi s study reviews current information on the functions of p27(Kip1), its abno rmalities found in human tumors, and the possible clinical implications of these findings with respect to the management of cancer patients. (C) 2000 Wiley-Liss. Inc.