GPX4 and cancer: A recent study showed that circPVT1 was significantly upregulated in 5- fluorouracil-resistant ESCCs, and the knock-down of circPVT1 significantly reduced the expression levels of GPX4 and SLC7A11, which indicated that the overexpression of circPVT1 could upregulate the expression of GPX4 and SLC7A11, thus enhancing the ferroptosis resistance and chemotherapy drug resistance of cancer cells.