Following this rationale, families of proteins that have aberrant expression in different tumor types, also known as cancer/testis antigens (CTA), like Melanoma Antigen Genes (MAGEs), Sarcoma Antigen Genes (SAGEs), Carcinoembryonic Antigens (CEAs), and New York Esophageal Squamous Cell Carcinoma 1 (NY-ESO-1), have been revealing their importance in the prognoses of different types of cancer, and can be used as promising targets in immunotherapy [64,67,68]. This evidence concerns the gene CEACAM5 and cancer.