Comparison of topoisomerase and MIB-1 expression in uterine cervical squamous lesions

The aim of this study was to assess the role of MIB-1 in the classification of cervical squamous lesions and to compare it with a novel proliferation marker, topoisomerase IIα (TP IIα). We classified 46 archival uterine cervical cases into 6 groups: normal (n = 3); human papillomavirus (n = 15); mild (n = 10), moderate (n = 7), and severe (n = 6) cervical intraepithelial neoplasia; and invasive carcinoma (n = 5). The formalin- fixed, paraffin-embedded tissue sections were stained with monoclonal antibodies to Ki-67 (MIB-1) and TP IIα with a standard streptavidin immunohistochemical technique, with antigen retrieval to assess enzyme presence. The results were based on nuclear staining and percentage of positivity. We found that the mean percentage of positive nuclei increased from normal through increasing grades of dysplasia to its maximal level in invasive carcinoma. The level of positive nuclei in the epithelium also generally increased from basal to full thickness with progression of the lesions. The correlation between the percentage of nuclei positive for both antibodies with the use of linear regression was close, with an r value of 0.85. Our conclusions were that MIB-1 is an adjunct in the classification of squamous lesions of the uterine cervix and that TP IIα is a useful proliferation marker in this setting.