In the context of bladder cancer, circST6GALNAC6 has been shown to bind to small heat shock protein 1 (HSPB1) and block erastin-induced phosphorylation site of HSPB1, protectively in response to ferroptosis stress (Ser-15 site), thus activating the P38 MAPK pathway and facilitating cell ferroptosis [228]. The gene discussed is MAPK1; the disease is urinary bladder carcinoma.