CD4 and neoplasm: As a result, infiltrated Tregs can exert suppressive effects on effector CD8+ and CD4+ T cells either through direct cell-to-cell contact [5, 6] or indirectly by generating interleukin-10 (IL-10) and transforming growth factor β (TGFβ) in situ [7–9], which helps tumor cells to evade the immune system.