FSTL1 and neoplasm: For instance, CAFs promote ferroptosis in NK cells by upregulating iron-inducible regulatory genes Ferroportin1 and Hephaestin and enhancing Follistatin Like 1 (FSTL1) secretion, leading to elevated free iron, upregulated NCOA4, iron-dependent lipid peroxidation in NK cells, and ultimately suppressed their anti-tumor activity 65.