CEACAM5 and neoplasm: CEA comprises an important tumor marker associated with several physiopathological processes of tumorogenesis, such as immunological defense, cell adhesion, cell survival, and metastasis, and its expression is induced by hypoxia-inducible factor α (HIF-α), suggesting that CEA plays an important role as a microenvironmental factor during tumorogenesis and confers a worse prognosis [9,49,50].