In general, the induction of T lymphocyte activation, proliferation, and function not only requires recognition between the T cell receptor (TCR) and specific major histocomptability complex (MHC) peptide complexes expressed on the surface of APCs (such as DCs and tumor cells), but also the interaction between co-stimulatory molecules on T cells and APCs [44]. The gene discussed is HLA-C; the disease is neoplasm.