As shown in Supplementary Fig. S2, the upregulation of ferroptosis related genes including PROM2, Ferritin, SLC7A11, and GPX4 was confirmed by immunohistochemistry analysis in BLCA tissues compared with normal tissues, which suggested that ferroptosis is associated with BLCA tumorigenesis. This evidence concerns the gene PROM2 and bladder transitional cell carcinoma.