Abstract

AIMS--To determine the best of five antibodies for immunohistochemical assessment of growth fraction in formalin fixed, paraffin wax embedded tissues. METHODS--Sections from 100 recent, and 17 ten year old or over wax embedded blocks of normal and malignant tissues were immunostained with monoclonal Ki67, polyclonal Ki67, PC10, MIB1, and JC1. The antibodies were evaluated for specificity of nuclear versus cytoplasmic staining, cleanliness of background, and compared with the expected pattern of staining in normal tissues, defined immunohistochemically by monoclonal Ki67 antibody in frozen tissues or by tritiated thymidine uptake. RESULTS--No marker was ideal, but best results were obtained with MIB1 and polyclonal Ki67, followed by JC1, PC10, and monoclonal Ki67. CONCLUSIONS--For routine use, MIB1 or polyclonal Ki67 are the best proliferation markers in conventional histological preparations. The other markers tested cannot be recommended.