IFNG and neoplasm: CD4+ T cell subtypes can have distinct roles in immunity, i.e., Th1 cells support cytotoxic responses through secretion of IL-2, TNF-α and IFN-γ, promoting activation of other effector T cells and antigen presentation (25, 26); Th2 generally promote tumor growth (27): and Th17 cells play dual roles, enhancing CTL recruitment via chemokine secretion but also promoting angiogenesis (28).