Unsurprisingly, other factors that may promote polyunsaturated fatty acid phospholipid (PUFA-PL) synthesis and peroxidation (such as FATP2 and MPO), or that may cause GPX4 inhibition (such as hypoxia in the tumor microenvironment), may also influence the inhibitory activity of tumor PMN-MDSCs. This evidence concerns the gene GPX4 and neoplasm.