ESR2 and testicular seminoma: Using the JKT-1 cell line derived from a human testicular seminoma [13], we have shown that E2 was able to inhibit human seminoma cell proliferation in vitro through an ERβ dependent mechanism [11], suggesting that ERβ acts on germ cells as a tumoral suppressor according to the observations performed on neonatal gonocytes of ERβ–KO mice [14].