We genotyped DNA isolated from the peripheral blood of a total of 286 patients with high-risk melanoma who participated in a prospective multicenter randomized phase III trial of adjuvant interferon and a panel of 288 randomly selected healthy unrelated Greek individuals from the Donor Marrow Registry of the National Tissue Typing Center, Athens, Greece that served as a control population for 6 CTLA4-SNPs of potential interest – namely CT 60, AG 49, CT 318, JO 27, JO 30 and JO 31. The gene discussed is CTLA4; the disease is melanoma.