SCD and breast cancer: One well-established cause of ferroptosis resistance is genetic mutations and epigenetic changes in cancer cells [39], which lead to abnormal function of these genes, including phosphatidylinositol 3-kinase (PI3K), serine/threonine kinase 11 (STK11), Kelch-like ECH-associated protein 1 (KEAP1), and SREBP2 etc. Activating mutation of PI3K, a highly frequent event in human cancer, confers ferroptosis resistance by hyperactivation of mTOR-SREBP1-SCD1 signaling in breast cancer cells [40].