Diagnostic Value of Protein Ki67 (MIB-1) in Atypical Pap Smears of Postmenopausal Women

Background: Atrophic epithelium of cervix sampled from postmenopausal women may mimic high-gradecervical intraepithelial neoplasia in Papanicolaou-stained (Pap) smears. Ki-67 (MIB-1) protein presents onproliferating cells, and percentage of cells with positive nuclei provides a reliable tool for rapid evaluation ofthe growth fraction. The aim of this study was to determine the diagnostic value of protein Ki67 staining inatypical pap smears of postmenopausal women.
Methods: In a case-control setting, pap smears of 75 womenwith an atypical pap smear (case group) and 75 with normal pap smears (controls) were obtained before andafter estrogen treatment. Afterward, samples were exposed to the monoclonal antibody Ki-67 (MIB-1) and theimmunohistochemically demonstrated Ki-67+ cells were compared.
Results: Mean ages of cases and controlswere 60.4±4.5 and 59.9±4.3 years respectively (P=0.50). There was one (2.7%) positive Ki-67 specimen in thecase group, without any positive Ki-67 specimen in the control group (P=0.50).
Conclusions: Measurement ofproliferative activity index in Pap smears restrained with MIB1 is a simple, reliable, and cost-effective methodfor excluding negatives. This would imply that it might allow a substantial reduction of diagnostic estrogencourses and subsequent Pap smears in postmenopausal women with atypical findings.