PRF1 and neoplasm: One such candidate is IL-12, which strongly enhances the response of innate and adoptive immune cells to cancer cells.128 IL-12 increases interferon (IFN)-γ secretion and the expression of granzyme B and perforin by T cells129 and NK cells,130 and suppresses tumour-induced T-regulatory (T-reg) cell proliferation.131 As a consequence, these mechanisms may enhance additional tumour clearance by bystander NK cells and conventional T cells, and counteract the ability of T-reg cells to promote tumour growth.