Prognostic role of p27Kip1 expression in oral squamous cell carcinoma in Taiwan

The cyclin-dependent kinase inhibitor p27Kip1 can inhibit the G1 to S transition of the cell cycle and is a putative tumor suppressor. Decreased expression of p27Kip1 protein has been correlated with poor prognosis in a variety of human tumors. We examined the expression of p27Kip1 in oral squamous cell carcinoma (SCC), epithelial dysplasia (ED) and normal oral mucosa (NOM) using antibodies to p27Kip1. Positive p27Kip1 nuclear staining was detected in all the specimems from ED and NOM, whereas positive p27Kip1 staining was observed in 16 of the 63 (25%) cases of oral SCC. The labeling index for p27Kip1 protein was significantly reduced from NOM through ED to oral SCCs, indicating that changes of p27Kip1 protein expression may be an early event in oral carcinogenesis in Taiwan. The Kaplan-Meier analysis showed patients with p27Kip1-positive tumors had significantly higher overall survival than those with p27Kip1-negative tumors in a total of 63 patients (P=0.015) and 47 patients with areca quid chewing habit (P=0.026). Multivariate analysis showed decreased p27Kip1 protein expression was an independent significant predictor of poor overall survival in the patients with oral SCCs. These results indicate that p27Kip1 protein expression may serve as a putative new adjuvant prognostic marker for routine assessment of oral SCC patients. ? 2002 Elsevier Science Ltd. All rights reserved.