GPX4 and cancer: A potential workaround for cancer cells around impaired GPX4 production is that aside from the common dietary selenium compound selenite, there are other independent routes by which selenium could be obtained, in particular recycling of selenocysteine obtained from selenium carriers such as SEPP1, or from selenomethionine, both of which would involve the action of selenocysteine lyase (SCLY) in forming selenide from selenocysteine, prior to its conversion to selenocysteinyl-tRNA.