Tumor markers currently in use in the evaluation of breast cancer include (but are not limited to) cancer antigen 15-3 [3,4] and 125 [5] (CA15-3, CA 125), carcinoembryonic antigen [3,4] (CEA), and prolactin [6]; however these show little potential for early detection [7]. The gene discussed is CEACAM5; the disease is breast cancer.