HLA-A*02 is a class I major histocompatibility complex (MHC) allele which is part of the HLA-A group of human major histocompatibility complex (MHC) leukocyte antigens (HLA). HLA-A is a human MHC class I cell surface receptor and is involved in presenting short polypeptides to the immune system. These polypeptides are typically 7-11 amino acids in length and originate from proteins being expressed by the cell. Cytotoxic T cells in the blood “read” the peptide presented by the complex and should only bind to non-self peptides. If binding occurs, a series of events is initiated culminating in cell death via apoptosis.

New York oesophageal squamous cell carcinoma 1 (NY-ESO-1) is part of a well-characterized group of cancer/testis antigens (CTAs). Normally, NY-ESO-1 expression is restricted to germ cells and placental cells, however NY-ESO-1 is also expressed in several cancers including: neuroblastoma; myeloma; metastatic melanoma; synovial sarcoma as well as bladder; oesophageal; hepatocellular; head and neck; non-small cell lung; ovarian; prostate and breast cancers and is often associated with poor prognosis. NY-ESO-1 is also able to elicit a spontaneous immune response, being the most immunogenic among the CTA family members and is therefore the most promising CTA candidate target for cancer immunotherapy.

NY-ESO-1 is coexpressed with melanoma antigen gene C1, a member of the MAGE family of CTAs which is involved in cell cycle progression and apoptosis.