Human leukocyte antigen (HLA) A2 is a subset of MHC-class I molecules encoded by A*02 alleles. HLA-A2 is more common in Northern Asia and North America populations. MHC class I antigens associated with B2-microglobulin are expressed by all human nucleated cells. MHC class I molecules are involved in presentation of antigens to CD8+ T cells playing an important role in cell-mediated immune responses and tumor surveillance.