The non-regulated overexpression of CEA plays an important role in the development of many cancer cells, including inhibiting cell loss and apoptosis (Ordoñez et al., 2000), destroying cell polarization and tissue structure (Ilantzis et al., 2002), and inhibiting differentiation procedures (Ilantzis et al., 2002; Eidelman et al., 1993). The gene discussed is CEACAM5; the disease is cancer.