CD8A and gastric cancer: Full-length MAGEA3 protein also contain epitopes for both T cells that carry the CD4 or CD8 antigen that have been detected in people with cancer; these epitopes can generate protective immunity through binding MHC class I or MHC class II molecules (63, 64), so injected MAGEA3 protein can induce the high-level humoral and cellular immune responses, and a large proportion of gastric cancer patients who were MAGEA3 positive identified by ELISA may be candidates for immunotherapy.