FATE1 (fetal and adult testis expressed 1), also known as FATE, CT43 (cancer/testis antigen 43) or BJ-HCC-2, is a cancer/testis antigen found in testis and tumor tissues (specifically hepatocarcinoma cells). Its expression is regulated by SF-1 (Steroidogenic Factor 1) and WT1 (Wilms’ tumor protein), two proteins involved in tumorigenesis, suggesting a role for FATE1 in tumor development. FATE1 is exclusively expressed in testis of the 6-11 week old fetus (around the period of gonadal sex differentiation). At 7 weeks, FATE1 is coexpressed with SRY and may play a role in early testicular differentiation. In adults, although predominantly expressed in testis, FATE1 can also be found in heart, kidney, brain, lung and adrenal gland. Mutations in the gene encoding FATE1 may be contributing factors in male infertility.