CD4 and neoplasm: In the process of tumour immune escape, Tregs can secrete TGF-β, IL-10, and IL-35 (Ebi3-IL-12α heterodimer) [29], which downregulate antitumour immunity, suppress antigen presentation by DCs, CD4+ T helper (Th) cell function and generate tumour-specific CD8+ cytotoxic T lymphocytes (CTLs).