[Expression of p21 WAF1/CIP1 protein in colorectal cancers: study of its relation to p53 mutation and Ki67 antigen expression].

Mutations of the p53 gene are the most common genetic alteration in malignant human tumors. A cyclin-dependent kinase inhibitor, p21WAF1/CIP1, is thought to be an important mediator of p53-induced cell cycle arrest. Although numerous studies have reported p53 expression and mutation in colorectal cancer few of them have correlated p53 expression with that of its downstream effector p21 and with the proliferation index as measured by expression of the Ki67 nuclear antigen.