HLA antigens in patients with germ cell cancers of the testis.

The expression of HLA-A, -B, -C, and -DR antigens has been analyzed in 145 unrelated Caucasian patients with germ cell tumors of the testis. Eighteen of these patients had pure seminoma, while the remaining patients had nonseminomatous tumors with embryonal carcinoma, teratocarcinoma, choriocarcinoma, and/or yolk sac components, with or without seminoma. Increases were noted in the frequencies of Aw33, B5, DR5, and DRw6 among the patients with pure seminoma, A3 and B7 among the patients with embryonal carcinoma with or without seminoma, and Aw32 among the patients with yolk sac tumor components. A decrease in the frequency of HLA-DR3 was noted in all patients subgroups, although none of these differences were statistically significant after correction for the number of antigens tested. HLA typing results for three affected brothers of patients indicate that, in each family, the affected sibling pair share at least one HLA haplotype. The etiological and prognostic significance of this finding and of the increases in a few HLA antigen frequencies in particular patient groups and the overall decreases in DR3 remain to be determined.