Lack of independent prognostic significance of p21 and p27 expression in advanced ovarian cancer: an immunohistochemical study.

The eukaryotic cell cycle is controlled by protein complexes consisting of cyclin-dependent kinases and cyclins. The cyclin-dependent kinases are in turn negatively regulated by a family of cyclin-dependent kinase inhibitors, comprising, among others, the p21 and p27 proteins. p21 and p27 have been shown to be of prognostic significance in a broad array of human tumors. Using immunohistochemistry, the frequency of expression and the possible prognostic and predictive significance of these proteins were examined in a series of 185 uniformly treated patients with stage III ovarian cancer. We found p21 to be overexpressed in 48% of cases. No significant correlation was found between the expression of p21 and p53 proteins (P = 0.273). A low level of p27 was demonstrated in 48.5% of cases. p21 overexpression correlated with lower Fédération Internationale des Gynaecologistes et Obstetristes substage, lower patient age, and absence of ascites, but neither p21 nor p27 expression was of prognostic significance for the whole group of patients. Only a trend toward reduced survival (P = 0.092) was noticed for the small subgroup of patients (6%), whose tumors lacked p27 expression completely. A clear positive correlation could be found between p21 and p27 protein expression (P = 0.012). Despite the suggested role of the 21 and p27 proteins in determining drug sensitivity, they were not found to be predictive for response to chemotherapy, as assessed by second-look laparotomy in this large group of patients with advanced ovarian cancer.