p27Kip1 Expression and Apoptotic Index in Prostatic Adenocarcinoma

Nam, Eun Sook; Kim, Duck Hwan; Shin, Hyung Sik; Park, Young Euy; Yang, Dae Yul

Abstract

p27kip1, a cyclin dependent kinase inhibitor, has been recognized as a negative regulator of cell cycle. To investigate the role of p27kip1 on progression of cancer and apoptotic pathway, we analyzed p27kip1 expression using immunohistochemical stain in 40 cases of prostatic adenocarcinoma and apoptotic index by TUNEL method in 30 cases of prostatic adenocarinoma. Both were correlated with Gleason grade and Gleason score. Loss of p27kip1 expression was more frequent in prostatic adenocarcinomas of higher score (Gleason score 7 to 10) (60.7%) than in those of lower score (Gleason score 4 to 6) (33.3%) (p<0.05). The value of mean apoptotic index of carcinoma was 1.13+/-0.26, 1.80+/-0.91, 2.06+/-0.79, and 2.12+/-0.82 in grade 2, 3, 4, and 5, respectively, and was positively correlated with grade of carcinoma (p<0.05). Mean apoptotic index of higher Gleason score (score 7 to 10; 2.05+/-0.63) was also significantly increased than in lower Gleason score (score 4 to 6; 1.34+/-0.39) (p<0.05). Mean apoptotic index in cases with and without p27kip1 expression was 1.92+/-0.86 and 1.89+/-0.81, respectively (p>0.05). These results suggest that loss of p27kip1 expression and increased apoptotic index may be the morphologic markers to predict the behavior of prostatic adenocaricnoma. The role of p27kip1 on apoptotic pathway seems to be meager in this study and needs further study.