Deregulated apoptosis of germ cells may contribute to malignant transformation as well as male infertility. We analyzed expression of the inhibitor of apoptosis survivin by polymerase chain reaction (PCR) in testicular germ cell tumors (TGCTs, n=28), normal testes (n=19) and testes with defective spermatogenesis (n=22). In a subset of samples (n=35), survivin transcript levels were quantified using real-time PCR. While survivin mRNA was expressed at high levels in undifferentiated TGCTs and normal testes, it was lost in mature teratomas and germ cell aplasia. Survivin expression in both normal and transformed germ cells is in contrast to its sharp differential expression in other tissues. Survivin expression correlates with the differentiation state of TGCTs and may be relevant for their tumorigenesis and malignant potential.