Expression of MAGE-A1, MAGE-A3/4 and NY-ESO-1 cancer-testis antigens in fetal testis.

Immunohistochemical expression of MAGE-A1, MAGE-A3/4 and NY-ESO-1/LAGE-1 cancer testis antigens (CTA) was assessed in 24 fetal testes from 15th to 36th week of gestation. Three monoclonal antibodies were used for immunohistochemical staining: 77B recognizing MAGE-A1, 57B recognizing multiple MAGE-A CTA, and D8.38 recognizing NY-ESO-1/LAGE-1. Expression of MAGE-A1 was not observed in fetal testis samples, whereas multi-MAGE-A and NY-ESO-1/LAGE-1 specific reagents stained pro-spermatogonia in all samples with different expression levels during the period of fetal development observed. Significant expression of MAGE-A3/4 and almost continuous expression of NY-ESO-1 in fetal testes after 22nd week of gestation suggested their important role in the development of sex cords and pro-spermatogonia in particular.