The diagnostic value of Ki-67 and repp86 in distinguishing between benign and malignant mesothelial proliferations.

Abstract

Abstract Context.—The differentiation of benign mesothelial proliferations from malignant mesotheliomas may be difficult, especially when evaluating small specimens from pleural biopsies. Objective.—To explore the potential value of 2 proliferative cell markers, Ki-67 and restrictedly expressed proliferation–associated protein 86 kDa (repp86), in distinguishing between malignant mesothelioma (MM) and benign reactive mesothelial hyperplasia (MH). Design.—Thirty-six cases of MM from 26 men and 10 women with a mean age of 62.9 years (range, 36–80 years) and 22 cases of benign reactive MH from 14 male and 8 female patients with a mean age of 51.5 years (range, 15– 88 years) were included in this study. The proliferative status of the lesions was assessed by immunohistochemistry using monoclonal antibodies to Ki-S2 (repp86) and Ki-S5 (Ki-67). The labeling indices were quantified. Results.—The mean labeling indexes for Ki-67 in MM and benign reactive MH were 24.6% (range, 1%–66%) and 6.23% (range, 0%–25%), resp...