Prognostic Significance of MIB-1 (Ki-67) Expression in Prostate Cancer and Matched Lymph Node Metastases

Abstract

MIB-1 is a marker expressed only in proliferating cells. The aim of this study was to evaluate the MIB-1 (Ki-67) labeling index in primary prostate cancer and matched nodal metastases for its prognostic value. Forty radical prostatectomy specimens from 2008 to 2009 were randomly selected for this study. Tumor blocks were immunostained using the monoclonal antibody MIB-1 (Dakorp. Denmark). MIB-1 expression was evaluated as the percentage of positive nuclei of all tumor cells. A mean of 1000 cells were analyzed in each case. There were highly significant differences between primary tumors with negative metastases versus primary tumors with lymph node metastases (p=0.0001), and primary tumors with lymph node metastases versus lymph node metastases (p=0.004). Our data indicate that the assessment of cell proliferation using MIB-1 as a proliferation marker has predictive value in prostate cancer patients with lymph node metastases.