While FSP1 inhibition was previously reported to enhance GPX4 inhibitor–induced ferroptosis in parental cancer cells (39, 42, 43), we found that nontoxic concentrations of the FSP1 inhibitor iFSP1 sensitized persister cells to GPX4 inhibitor more than parental cells (Fig. 2, F to I, and fig. The gene discussed is GPX4; the disease is cancer.