Prognostic value and potential biological functions of ferroptosis-related gene signature in bladder cancer

Bladder cancer (BC), as a genitourinary system tumor, is a highly prevalent tumor type. Ferroptosis is an iron-dependent oxidative cell death mechanism that is becoming increasingly recognized as a promising avenue for cancer therapy. However, further determination of the prospective prognostic value of ferroptosis for BC and investigation of the underlying mechanisms is required. The mRNA expression profiles and associated clinical data were downloaded from public databases such as The Cancer Genome Atlas, Gene Expression Omnibus and the IMvigor210 database. To construct a predictive formula, the least absolute shrinkage and selection operator Cox regression algorithm was used. In addition, a prognostic multigene signature was constructed using previously selected ferroptosis-related genes (FRGs). A total of 28 FRGs were differentially expressed between tumor and normal samples with |log2 fold change| >1 and adjusted P<0.05. A prognostic model was then established and it was validated in the GEO cohort using six genes: Glutamate-cysteine ligase modifier subunit, crystallin α-B, transferrin receptor, zinc finger E-box binding homeobox 1, squalene epoxidase and glucose-6-phosphate dehydrogenase (G6PD). Numerous important pathways involved in the development of the immune system and cancer were indicated to be significantly different between the two risk groups. In addition, it was discovered that G6PD expression subgroups that were associated with immunotherapy response in patients with BC had similar prognostic features to risk score subgroups. In the present study, a gene signature with a prognostic value for ferroptosis in BC was successfully developed and the potential value of G6PD was identified for future research.