CircIL4R directly sponges microRNA-541-3p, and inhibition of miR-541-3p mitigated the effects of circIL4R knockdown on HCC cells; this suggests that circIL4R served as a tumor promoter and ferroptosis inhibitor in HCC by the miR-541-3p/GPX4 network (Xu et al., 2020). The gene discussed is GPX4; the disease is hepatocellular carcinoma.