Elevated serum or CSF biomarkers including alpha-fetoprotein, beta-human chorionic gonadotropin, and placental alkaline phosphatase are suggestive of germ cell tumors, but the biomarker that tends to be elevated differs depending on the included tumor subtypes [59]—elevated alpha-fetoprotein: immature teratoma, embryonal carcinoma, and yolk sac tumor; elevated beta-human chorionic gonadotropin: choriocarcinoma and some germinoma and embryonal carcinoma cases; elevated placental alkaline phosphatase: germinoma. This evidence concerns the gene AFP and yolk sac tumor.