Specific tumor markers that can be used to confirm a diagnosis of NM are carcinoembryonic antigen (CEA) for carcinoma; human chorionic gonadotropin (beta-hCG) for choriocarcinoma, embryonal carcinoma, or germ cell tumor; alpha-fetoprotein (AFP) for teratocarcinoma, yolk sac tumor, embryonal carcinoma, or endodermal sinus tumor; CA-125 for ovarian cancer; CA 15-3 for breast cancer; prostate-specific antigen (PSA) for prostate cancer; and melanin for melanoma. The gene discussed is CEACAM5; the disease is breast cancer.