Testicular cancer in father and son

The occurrence of testicular tumors in closely related family members is rare. We report a case of testicular cancers in a father and son. The father had pure seminoma, and his son developed a mixed nonseminomatous germ cell tumor. The peripheral blood lymphocytes in both patients were tested for 52 HLA specificities, and the patients were found to have six in common. The son was homozygous for HLA A24. The association between certain HLA antigens, other genetic factors, and testicular cancer requires further study to improve the care and counseling of patients and their families.