TSPY expression is up-regulated in testicular seminoma [24], some non-seminomatous germ cell tumors [25], carcinoma-in situ (CIS) [15,26] and gonadoblastoma [27,28,29], and the TSPY gene is regarded as the candidate for GBY, the elusive gonadoblastoma locus on the human Y chromosome that is thought to have a normal function in the testis but to act as an oncogene in the dysgenetic gonad of XY-sex-reversed and intersex humans [30]. The gene discussed is TSPY1; the disease is testicular germ cell tumor.