GPX4 and neoplasm: Depression of circIL4R abrogates oncogenesis and accelerates ferroptosis of HCC cells by sponging miR-541-3p to suppress the expression of GPX4, suggesting that circIL4R functions as a tumor promoter and a ferroptosis inhibitor in HCC via the miR-541-3p/GPX4 axis (Xu et al., 2020).