Glutathione S-transferase isoenzymes in human renal carcinoma demonstrated by immunohistochemistry.

Glutathione S-transferase (GST) in man comprise at least four gene families. Three of these families give rise to cytosolic isoenzymes (alpha, mu and pi classes), whilst the remainder is membrane bound and has been called microsomal GST. These enzymes are implicated in tumourogenesis and both pi class GST and alpha class GST have been described in four cases of human renal cell carcinoma. Using specific polyclonal rabbit antisera we have demonstrated by immunohistochemistry that all 12 renal carcinomas studied contained GST pi. Most tumours also contained GST alpha, GST mu and microsomal GST isoenzymes but their distribution was heterogeneous and sometimes very focal. This heterogeneity of GST isoenzyme distribution within tumours has not been well documented previously, but is relevant to our understanding of the functions of GST, and to the interpretation of biochemical quantification experiments using tissue extracts.