Immunohistochemical study of alpha, mu and pi class glutathione S transferase expression in malignant melanoma. MMM Group. Multidisciplinary Malignant Melanoma Group.
Human pi, mu and alpha class glutathione S transferases (GST) have been localized immunohistologically in normal skin, naevi and melanoma. Pi GSTs were found principally in the stratum basalis and, to a lesser extent, in the superficial layers. Normal melanocytes showed strong nuclear and cytoplasmatic staining. Distribution of GST mu in the epidermis showed that only the stratum basale, where melanocytes are located, stained well but with weak nuclear staining. Normal melanocytes were also well stained. The alpha GSTs were relatively abundant in the upper strata and to a lesser extent, in the basal layers. The absence of nuclear staining gives these cells a target appearance. Normal melanocytes showed strong cytoplasmatic staining. The pi GSTs seem to be most persistently and strongly expressed in malignant melanoma (MM), but mu GSTs are also found, whereas the alpha GSTs were only occasionally present. The finding of the GST mu in the melanocytes of the basal layer raises new questions regarding the role of GST mu in these cells because of the inherent risk of MM in individuals with a congenital deficiency of this isoenzyme. The role of GSTs in the resistance of cells to chemotherapy is also discussed.
Moral
A
A
Department of Surgery, Hospital Clinic, Barcelona, Spain.
Palou
J
J
Lafuente
A
A
Molina
R
R
Piulachs
J
J
Castel
T
T
Trias
M
M
D002467:Cell Nucleus / Q000201:enzymology; D003593:Cytoplasm / Q000201:enzymology; D004848:Epithelium / Q000201:enzymology; D005982:Glutathione Transferase / Q000378:metabolism*; D006801:Humans; D007150:Immunohistochemistry; D007527:Isoenzymes / Q000378:metabolism*; D008544:Melanocytes / Q000201:enzymology; D008545:Melanoma / Q000201:enzymology*; D009363:Neoplasm Proteins / Q000378:metabolism*; D012878:Skin Neoplasms / Q000201:enzymology*
D007527:Isoenzymes; D009363:Neoplasm Proteins; D005982:Glutathione Transferase