CD4 and neoplasm: B cells of the adaptive immune system have also emerged as playing anti-tumorigenic roles through (1) release of tumor antigen-specific antibodies (once B cells differentiate into plasma cells) that trigger antibody-dependent cellular cytotoxicity (ADCC) by NK cells or complement-dependent cytotoxicity (CDC), and (2) B cell receptor-mediated antigen presentation to CD8+ or naïve CD4+ cells for tumor killing [9,10,11].