SPECIFIC EXPRESSION OF GLUTATHIONE-S-TRANSFERASE-PI FORMS IN (PRE)NEOPLASTIC TISSUES - THEIR PROPERTIES AND FUNCTIONS

The detection of preneoplastic cells is very important for the analysi s of carcinogenic processes and for developing strategies for preventi on and treatment of cancer. We have been investigating enzyme alterati ons occurring during rat chemical hepatocarcinogenesis, especially to find more specific enzyme markers for preneoplastic hepatic lesions. W e identified the placental form of glutathione S-transferase (GST-P; G ST 7-7) as a new marker enzyme for preneoplastic hepatocytes. We also found human placental form, GST-pi, to be a possible tumor marker for various human tissues except liver. In this article, their properties and possible functions are reviewed on basis of our recent investigati ons. A peroxisomal enzyme, enoyl CoA hydratese, in also described as a possible negative marker for rat preneoplastic hepatic foci/nodules a nd hepatomas induced by peroxisome proliferators.