p21 (WAF1/CIP1) protein expression is associated with prolonged survival but not with p53 expression in epithelial ovarian carcinoma

Objective. The objective of this study was to clarify the influence of p21 protein expression in ovarian cancer. p21 (WAF1 [wild-type p53 activated fragment 1]/CIP1) is a universal cyclin-dependent kinase inhibitor and can be induced as a downstream effector of the p53 tumor suppressor gene. Methods. The expression of p21 was evaluated by immunohistochemical analysis with the monoclonal antibody WAF1 (Oncogene Science) on 106 formalin-fixed, paraffin-embedded tissue samples of epithelial ovarian cancer. Results. p21 was expressed in 65 (61%) of all cases. p21 expression was associated with early stage in FIGO classification (FIGO I and II, P = 0.003) and no tumor residues after primary tumor resection (P = 0.018). Immunohistochemical staining results were judged as negative if no tumor nuclei were stained, as weak positive if 1-49% were stained, and as strong positive if over 50% of nuclei were stained. Clinical follow-up showed a better overall survival for cases with strong p21 expression (79 months) versus 40 months for weak expression and 30 months for no expression (P = 0.033). Previously determined p53 expression of this cohort was compared with p21 status. p53 overexpression was observed in 49 cases (48%) and showed no association with p21 expression. Conclusion. No correlation was found between p21 and p53 expression. p21 expression is a significant prognostic marker for improved survival in ovarian cancer and is associated with early FIGO stage and zero tumor residues after primary tumor resection. (C) 2000 Academic Press.