Combining HPV and MIB-1 tests reduces the number of colposcopies in women with equivocal cytology

Background. In this study the MIB-1 immunostaining pattern as an index of cellular proliferation was analyzed in smears diagnosed as borderline dyskaryosis in order to establish whether the combination of human papillomavirus testing and MIB-1 staining could resolve equivocal cytology. Methods. Conventional Pap smears of 108 women diagnosed as borderline dyskaryosis were stained with MIB-1 and the proliferation index was assessed. These women were evaluated by colposcopy, histological sampling, and human papillomavirus, semi-quantitative evaluated by hybrid Capture II test. Results. All 64 human papillomavirus- and MIB-1-negative women had no underlying high-grade cervical intraepithelial neoplasia or cervical cancer. Forty of the 104 women with normal histology or cervical intraepithelial neoplasia I were positive for human papillomavirus, compared to only one positive MIB-1 test (i.e. proliferation index of more than 35%). Conclusions. Adding a MIB-1-test in human papillomavirus-positive women with equivocal cytology might reduce the number of colposcopies needed to predict ≥ cervical intraepithelial neoplasia II. With this approach only four instead of 43 human papillomavirus-positive women would have been referred for colposcopy.