Expression of Fas and Fas ligand in the testes and testicular germ cell tumors: an immunohistochemical study.

The Fas-Fas ligand system plays a crucial role in the production of a signal for apoptosis in the immune system. In the present study, expression of Fas and Fas ligand in the testes and testicular germ cell tumors was examined immunohistochemically. Expression of both Fas and Fas ligand was found on Leydig cells, Sertoli cells, and germ cells in the testis, and on epithelial cells in the epidydimal duct. Expression of both Fas and Fas ligand was also found in all 23 seminomas, 8 embryonal carcinomas, and 3 yolk sac tumors which were examined in this study. Western blot analysis after sodium dodecyl sulfate (SDS) polyacrylamide gel electrophoresis under a reducing condition with tissues of the thymus, the testis, and a seminoma showed a single major band bound to the antibody for Fas or Fas ligand at the position of molecular weight slightly more than 47.5 kilodalton. Since both Fas and Fas ligand are expressed on normal testicular cells, and on cells of testicular germ cell tumors, the Fas-Fas ligand system in these cells seems to play a role other than producing a signal for apoptosis.