When TCRs recognize antigens presented by MHC molecules on the surfaces of tumor cells or antigen-presenting cells, the CD3 and TCR zeta chains’ phosphorylation is essential during MHC-driven antigen presentation, initiating a cascade of downstream signaling leading to T-cell activation, proliferation, and differentiation, whose impairment can cause tumor immune evasion [40]. The gene discussed is HLA-C; the disease is neoplasm.