TGFB1 and cancer: First, the cancer-associated fibroblasts (CAFs) suppress antitumor immunity by restricting T cells to stroma and preventing them from accumulating in the vicinity of cancer cells through the production of dense extracellular matrix (ECM) such as collagen and hyaluronan, as well as through the secretion of suppressive cytokines such as TGF-β and CXCL1210.