GLUTATHIONE-S-TRANSFERASE GSTM1 PHENOTYPES AND PROTECTION AGAINST CUTANEOUS TUMORS

Multiple allelism at loci encoding detoxicating enzymes is associated with cancer risk. We have studied genetic variation at the glutathione S-transferase GSTM1 locus to see whether phenotypes confer altered su sceptibility to basal cell carcinoma (BCC), squamous cell carcinoma (S CC), malignant melanoma (MM), or multiple skin tumours of different hi stological types. The frequency of GSTM1 null in cases and controls (5 2%) was similar, except for patients with two or more tumours of diffe rent types (71%, p = 0.033). GSTM1 A/B was reduced in frequency (p < 0 .05) in patients with single or multiple BCC. Thus GSTM1 A/B may be pr otective, and effectiveness of detoxication may be a factor determinin g susceptibility to skin cancer.