IGTS was first reported in 1982 by Logothetis et al. [6], who defined three criteria for IGTS: the tumor markers α-fetoprotein (AFP) and human chorionic gonadotropin (HCG) are normal, but the tumor size continues to increase during or after chemotherapy, and no components of nongerminomatous GCT other than mature teratoma are present. The gene discussed is AFP; the disease is teratoma.