GPX4 and cancer: To that matter, a recent study evaluated the co-essentiality network of the selenoprotein synthesis machinery within 485 human cancer cell lines and revealed a tight cluster encompassing genes for the selenoprotein synthesis machinery and three selenoproteins, SEPHS2, GPX4 and TXNRD1, suggesting that the machinery functions in most cancer cells to support the production of these selenoproteins [95].