Immunohistochemical localization or glutathione S-transferase alpha and piin human esophageal squamous epithelium, Barrett's epithelium and carcinoma

High tissue levels of glutathione S-transferases (GSTs), a family of detoxi fication enzymes, are inversely correlated with cancer risk in the human ga strointestinal tract, Patients with Barrett's esophagus, wherein squamous e pithelium is replaced by columnar epithelium, have an increased risk for de veloping esophageal adenocarcinoma. Biochemical analyses revealed that Barr ett's epithelium contains lower levels of GST enzyme activity as well as so me GST isoforms, as compared with squamous epithelium, So far,little inform ation on the immunohistochemical distribution of the GST alpha and pi isofo rms in normal squamous epithelium, in Barrett's metaplastic epithelium or i n adeno- and squamous cell carcinomas of the esophagus is available. Tissue s were fixed in formalin and embedded in paraffin, Three 4 mu m thick secti ons were used for hematoxylin and eosin staining and for immunostaining wit h antibodies against GST alpha and pi. GST alpha and pi were seen in normal squamous epithelium (0% and 75%, respectively), Barrett's epithelium (75% and 100%), adenocarcinoma (25% and 100%) and squamous cell carcinoma (27% a nd 91%), Staining was mainly cytoplasmic, though some nuclear staining with the CST pi antibody was apparent. The varying expression of GST alpha and pi in normal and (pre)neoplastic esophagus may have consequences for the tr eatment of these diseases and may contribute to an understanding of the dev elopment of these esophageal disorders.