CKB and neoplasm: Hepatocellular carcinoma: AKT activated by insulin-like growth factor 1 receptor (IGF1R) signaling phosphorylates creatine kinase B (CKB) at T133, reducing its metabolic activity and increasing its binding to and phosphorylation of GPX4 at S104, which prevents HSC70 binding to GPX4, thereby abrogating degradation of GPX4 by chaperone-mediated autophagy, inhibiting ferroptosis and promoting tumor growth in mice.164 Elevated expression of ribonucleotide reductase regulatory subunit M2 (RRM2) inhibits ferroptosis in HCC cells.