EVALUATION OF CELL-PROLIFERATION ANTIBODIES REACTIVE IN PARAFFIN SECTIONS

The monoclonal antibody Ki-67 has been used extensively to study tumor growth fractions by immunohistochemistry. However, use of this antibo dy has been restricted to frozen-section material or fresh unfixed cel ls. In this study, using a microwave technique, we show that Ki-67 and a number of other antibodies give results in paraffin sections simila r to those in frozen sections. In a prospective study, where formalin fixation was controlled, proliferation counts with monoclonal Ki-67, p olyclonal Ki-67, MIB-1, Ki-S5 and PC10 were compared with results from monoclonal Ki-67 on fresh-frozen tissue. These antibodies were also s tudied retrospectively with randomly chosen paraffin blocks from archi val, routinely fixed, material. Overall, monoclonal Ki-67, polyclonal Ki-67, MIB-1, and Ki-S5 (all recognize Ki-67 epitopes) gave similar re sults to monoclonal Ki-67 on frozen tissue. However, in a few cases, m onoclonal Ki-67 gave inconsistent results in paraffin sections. These antibodies also gave similar results in archival tissue. PC10 (anti-pr oliferating cell nuclear antigen) gave higher counts in both studies. MIB-1 gave excellent results on B5-fixed decalcified tissue. These ant ibodies are suitable for growth fraction estimation in routine formali n-fixed tissue.