Frequency of Ki-67 (MIB-1) and P53 expressions among patients with prostate cancer

Abstract

Prostate cancer is the most common malignant tumor in men. Tumor grade is one of the most important prognostic factors of prostate cancer. P53 and Ki-67 expressions have also been considered to be prognostic factors. This study was performed to investigate the frequency of these proteins expression and compare the obtained results with Gleason's grading. In this cross-sectional study, 49 paraffin blocks of prostate cancers were assessed. Tumor grade was determined according to the Gleason's criteria. Ki-67 and P53 expressions were determined by immunohistochemical staining. The obtained results were analyzed and evaluated using Spearman's statistical test (SPSS version 15). Three out of 49 (6.1%) cases were well differentiated, 21 (43%) moderately differentiated and 25 (51%) were poorly differentiated. P53 was negative in all well-differentiated cases. Ki-67 was negative in 14 cases (28%) including all well-differentiated tumors. Among moderately and poorly differentiated tumors Ki-67 was negative in eight (38%) and three (12%) of cases, respectively. A statistically significant relation was observed between the increased Ki-67 labeling index (LI) and increased Gleason's grade. Conversely, no statistically significant relation was found between P53 expression and increased Gleason's grade. According to the findings of this study, it seems that Ki-67 can be used as a prognostic factor for prostate cancer. On the other hand, the probable relation between P-53 and prostate cancer prognosis requires further studies.