PUTATIVE PRENEOPLASTIC CHANGES IDENTIFIED BY ENZYME-HISTOCHEMICAL ANDIMMUNOHISTOCHEMICAL TECHNIQUES

Microscopic evaluation of whole-mount colons stained with methylene bl ue and/or hexosaminidase has identified putative preneoplastic lesions in the colons of rodents treated with carcinogen and in the grossly n ormal colons of humans. Enzyme histochemistry with glycol methacrylate sections has permitted the identification of putative premalignant le sions in rodent livers, human and rodent colons, and human prostates. Immunohistochemistry with paraffin-embedded tissues has been used to i dentify and characterize putative premalignant lesions in human colons and prostates.