HLA antigens in familial and sporadic cutaneous melanoma

One hundred and twenty-four subjects belonging to 25 families, 51 with familial malignant melanoma (FMM), and 186 subjects belonging to 41 families, 41 with sporadic malignant melanoma, were typed for the HLA A, B, C and DR loci of the HLA system. There was the same statistically significant difference in the frequency of the haplotype A9, B35, Cw4 between each group of patients and the respective healthy relatives (p = 0.01, p = 0.01 and p = 4 x 10(-3), respectively). Moreover, the higher frequency of the haplotype A9, B35, Cw4 in the healthy members of the FMM families (42.46%) compared with the healthy members of the SMM families (23.44%) indicates that in the latter group other individuals are at risk for the disease. Furthermore, the different frequency of haplotypes B5, DR5 and B5, Cw1 suggest that differences exist between the two groups of healthy relatives. These observations confirm that the HLA region is involved in the etiology of malignant melanoma.