Utility of proliferation-associated marker MIB-1 in evaluating lesions of the uterine cervix

Abstract

Various cervical lesions at times may be difficult to distinguish from one another on routine hematoxylin and eosin stains, and immunostaining for the proliferation-associated antigen Ki-67, using monoclonal antibody MIB-1, can aid their distinction. The reduced MIB-1 expression in atrophy and increased MIB-1 expression in dysplasia permits easy distinction between these conditions. Presence of MIB-1 in more than 15% of basal cells and/or in surface half of the epithelium favor a diagnosis of condyloma over squamous metaplasia or inflammatory changes. Normal endocervix shows MIB-1 positivity in less than 10% of the cells, but usually in more than 20% of cells in cervical adenocarcinoma. With increasing grade of dysplasia, the percentage of MIB-1 positive cells is increased, and positive cells are seen in the higher levels of the epithelium. Presence of more than 20% MIB-1 positive cells in Pap smears showing atypical cells of uncertain significance is associated with a diagnosis of dysplasia on subsequent biopsies. Cauterized tissues with dysplasia show MIB-1 expression similar to adjacent noncauterized dysplastic areas. MIB-1 expression is, therefore, useful in evaluating various cervical lesions.