Carcinogenesis is a multistep accumulation of genetic lesions that may result in uncontrolled cellular proliferation, a decrease in cell death or apoptosis, blockage of differentiation, invasion and metastatic spread. Cancer prostate, like other types of cancer, is associated with loss of the cell cycle control, resulting in unregulated growth of cells. Several cyclin-dependant kinase inhibitors have been recently described. Among these P21 wafl, which is one of the major regulators of cell cycle.