Testicular germ cell cancers are a group of malignancies that occur in younger males (0-30 years old). The pathologies of these cancers include a Embryonal carcinoma, a Yolk sac tumor, a Choriocarcinoma, a Teratoma, a Polyembryona and a Gonadoblastoma. The strange thing about this group of malignancies is that they take on placental cytotrophoblast morphology. These cancer are totally driven by hyperglycosylated hCG made by cytotrophoblast cells, which drives the malignancy through antagonizing a TGFß receptor, exactly like hyperglycosylated hCG drives placental choriocarcinoma in women. Hyperglycosylated hCG levels can be extremely high in serum in these cases. The USA hCG Reference Service has seen one very extreme case with a total hCG and a hyperglycosylated hCG levels of 16,910,186 mIU/ml in serum. These cancers generally respond very well to chemotherapy treatment.