Commonly used markers in adults, such as cancer antigen 125 (CA-125), cancer antigen 19-9 (CA 19-9), cancer antigen 15-3 (CA 15-3), and carcinoembryonic antigen (CEA), play established roles in the detection and follow-up of malignancies including ovarian, colorectal, pancreatic, and breast cancers [1,3]. The gene discussed is CEACAM5; the disease is breast cancer.