CEACAM5 and cancer: It is now well established that tumour cells express antigens that are presented via MHCI molecules, and are recognised by CTLs derived from cancer patients [19,20,21], such as gp100, melanoma associated antigen (MAGE), New York oesophageal squamous cell carcinoma (NY-ESO), carcinoembryonic antigen (CEA) and cell tumour antigen (p53) [22,23,24,25].