Secondly, perturbations in the process of loading tumor antigens onto MHC molecules can occur, encompassing alterations in the immunoproteasome activity (resulting in peptide deficiency), impairment of peptide entry into the endoplasmic reticulum through transporter associated with antigen processing (TAP), and perturbations involving chaperone proteins [22, 27]. The gene discussed is HLA-C; the disease is neoplasm.