CD4+ T cells primarily mediate anti-tumour immunity by providing help for CD8+ CTL and antibody responses, as well as via secretion of effector cytokines such as interferon-γ (IFNγ) and tumour necrosis factor-α (TNFα), and, under specific contexts, via direct cytotoxicity against tumour cells (Fig. 2). This evidence concerns the gene CD4 and neoplasm.