PRF1 and neoplasm: It is supported by CD4 (+) helper T cells that produce IL-2 and interferon-gamma, resulting in an effector mechanism that ultimately leads to tumor elimination.[8,52,53] Cytotoxic lymphocytes recognize tumor-associated antigens and eliminate tumor cells by granule exocytosis (perforin and granzymes) and death ligands.[54] However, Th17, a subpopulation of CD4 + T cells, can produce IL-17 in TEM.