SELENOS and hepatocellular carcinoma: Increased immunoreactivity of GPX4 (a selenoprotein that protects against ferroptosis by scavenging lipid hydroperoxides) and HSPA9 (a member of the mitochondrial UPR) in HCC cells corroborated the transcriptional enrichment for the ferroptosis and UPR pathways (Fig. 2E, top and bottom).