SLC7A11 and cancer: Given that SLC7A11 is often highly expressed in different cancers, its overexpression can inhibit reactive oxygen species-induced ferroptosis, promote tumour growth, and confer drug resistance.14,15,65,66 ATF4 expression is also upregulated in different cancers to promote cell survival and tumour growth.36,37 Of note, ATF4 and SLC7A11 levels are positively correlated in human HCC (Fig. 7H), and ATF4-deficient HCC cells are more sensitive to ferroptosis (Fig. S7E).