Abstract

p27Kip1 protein, a negative cell cycle regulator in G1 progression, has been reported to be related with human cancers including colon, breast and non-small cell lung carcinomas. To elucidate a possible prognostic indicator, we studied 49 cases of human breast carcinoma for expression of p27Kip1 protein using an immunohistochemical method, and compared these results with known prognostic parameters of the breast cancer. p27Kip1 protein was intensely stained in nuclei of carcinoma cells in 26 cases (53.1%). The expression rate of p27Kip1 protein was significantly higher in higher nuclear grade (p<0.05), lower histologic grade (p<0.01), lower N classification (p<0.001) and lower clinical stage (p<0.05) than in lower nuclear grade, higher histologic grade, higher N classification and higher clinical stage, respectively. p27Kip1 protein expression was significantly correlated with progesterone receptor status (p<0.05) or cyclin D expression (p<0.05). No statistical correlations were found between expression of p27Kip1 protein and other parameters including tumor size, estrogen receptor status, p53 overexpression and c-erbB-2 expression. The results suggest that reduced expression of p27Kip1 protein plays a role in biologically aggressive behavior of breast carcinoma and might contribute in predicting breast cancer patient's survival.

• Keywords: Breast neoplasm;p27;Cyclin-dependent kinase inhibitor;Prognosis