The utilization of ferroptosis inhibitor Fer-1 could suppress the lipid peroxidation resulting from erastin, RSL3, and cysteine starvation in both JIMT1 and SKBR3, which also indicated the role of cysteine metabolism in modulating HER2-positive breast cancer ferroptosis (Figure 3—figure supplement 1G and H). The gene discussed is ERBB2; the disease is breast cancer.