Subcellular localization of p27kip1 expression predicts poor prognosis in human ovarian cancer.

PURPOSE The cyclin-dependent kinase inhibitor p27(kip1) regulates cellular progression from G(1) to S phase. Several studies have shown that loss of p27(kip1) protein expression is associated with disease progression in various malignancies. The purpose of this study was to evaluate the subcellular localization of this cyclin-dependent kinase inhibitor in a large cohort of primary ovarian carcinomas and compare the results with clinicopathologic variables and overall survival. EXPERIMENTAL DESIGN Subcellular localization of p27(kip1) was first assessed by Western blotting in nuclear and cytoplasmic extract from 13 cases of ovarian carcinoma. Subcellular localization of the p27(kip1) protein was evaluated using tissue microarrays containing 421 cases of ovarian carcinoma. RESULTS The presence of p27(kip1) in the cytoplasm regardless of the nuclear stain correlated strongly with late-stage disease (P < 0.03), extent of cytoreduction (P = 0.03), and shorter disease-specific survival (P < 0.0001). CONCLUSION Cytoplasmic localization of p27(kip1) predicts poorer prognosis in ovarian carcinoma, particularly in late-stage disease.