Li et al. (2019) found that the form of carbonic anhydrase 9 inhibiting multiple myeloma cell death under hypoxic conditions is mainly a mixed cell death of apoptosis and ferroptosis through autophagy process. In addition, studies have also found that cytoplasm actively controls ferroptosis by interacting with GPX4 to activate the autophagy degradation of GPX4 (Chen C.a. et al., 2021). This evidence concerns the gene CA9 and plasma cell myeloma.