The placental form of glutathione S-transferase as a new marker protein for preneoplasia in rat chemical hepatocarcinogenesis.

A neutral form of glutathione S-transferase (GST-P), which has a subunit of 26,000 (or 21,500) daltons and charge isomers with isoelectric points of 6.7 (major), 6.3 and 6.0, was purified from rat placenta cytosol. Immunohistochemical staining using anti-GST-P rabbit antibody demonstrated that GST-P, which is hardly detectable in normal liver, is markedly increased and localized in preneoplastic hepatic lesions such as hyperplastic nodules, indicating that GST-P could be a useful marker proteins for preneoplasia in chemical hepatocarcinogenesis.