In recent years, molecular biomarkers such as carcinoembryonic antigen (CEA), microsatellite instability (MSI), Kirsten Rat Sarcoma Viral Oncogene Homolog (KRAS) and B-Raf Proto-Oncogene Serine/Threonine Kinase (BRAF) gene mutation have been employed to aid prognosis in CRC. The gene discussed is CEACAM5; the disease is colorectal carcinoma.