IL6 and neoplasm: A direct effect of CAFs on T cell function was demonstrated in an in vitro study that utilized fibroblasts and tumor-infiltrating T lymphocytes (TILs) isolated from human lung tumors: CAF-derived IL-6 enhanced production of IFNγ and IL-17A in activated TILs, suggesting that fibroblasts may also have an immunostimulatory effect on T cells (76).