The CEACAM 5 gene, its product also known as CD66e codes for the carcioembryonic antigen (CEA) and has become one of the best-known members of the Ig-superfamily since it has a significant role in the clinical routine as a tumor marker for several tumor entities including gastrointestinal and respiratory malignancies [12]. The gene discussed is CEACAM5; the disease is neoplasm.