CD4 and neoplasm: Antigen-presenting cells (APCs) present tumor-associated antigens to CD8 + T cells through MHC class I molecules such as HLA-B. They also present antigens to CD4 + T cells through MHC class II molecules, including HLA-DPA1, HLA-DPB1, HLA-DRA, and HLA-DRB1, thereby eliciting antitumor immune responses [47].