Cyclin-dependant kinase inhibitors CIP1 (p21) and KIP1 (p27) in ovarian cancer

Purpose: Deregulation of the cell cycle is one of the important prerequisites for cancer development. p21 and p27 are both universal inhibitors of cyclin-dependant kinases and can therefore influence cell cycle or tumor progression. The aim of this study was to determine the influence of p21 and p27 expression on survival and chemotherapy response. Methods: 165 patients with ovarian cancer have been examined for p21 and p27 expression by immunohistochemistry on formalin-fixed, paraffin-embedded tissue using the monoclonal primary antibody WAF1 (Oncogene Science) and KIP1 (Transduction Laboratories). Results: High p21 expression (> 50%) correlates only with early tumor stage (P=0.04). There was no correlation found between p21 and p27 expression. Patients with high p27 expression (> 25%) had a longer DFS (disease free survival) in both univariate and multivariate analysis (P=0.05 and P=0.043) than patients with low p27 expression. A longer overall survival (OS) could only be proven for the group of high p27 expression in univariate analysis (P=0.03). Conclusion: p27 is an independent prognostic factor for ovarian cancer for DFS though this was not true for OS.