Expression of EPB41L2 in Cancer-Associated Fibroblasts: Prognostic Implications for Bladder Cancer and Response to Immunotherapy

Immunotherapy response in patients with bladder cancer (BLCA) treated with immune checkpoint inhibitors (ICIs) is variable. The accurate evaluation of immunotherapy efficacy may be facilitated by the tumor microenvironment (TME). Erythrocyte membrane protein band 4.1 like 2 (EPB41L2), a cytoskeletal protein with a regulatory role in the TME was intensively investigated to determine its biological characterization, clinical relevance, and predictive value for immunotherapy in BLCA.Comprehensive bioinformatics and statistical analyses were conducted to examine gene expression profile, TME components, immune contexture, molecular features, and prediction of immunotherapy response. Immunohistochemistry (IHC) validated the results of the bioinformatics analysis. Association between immune checkpoint genes (ICGs) and EPB41L2-based risk stratification was validated in the IMvigor210 cohort, and their association with ICI response was assessed.EPB41L2 mRNA levels were decreased in BLCA compared to normal tissue. IHC showed reduced EPB41L2 staining intensity in early BLCA tissue. Nevertheless, elevated EPB41L2 expression was observed in cancer-associated fibroblasts (CAFs) with higher histological grade and pathological stage. High EPB41L2 expression served as a poor prognostic factor for BLCA. Single-cell RNA-seq and further analyses revealed that EPB41L2 was mainly expressed in CAFs and promoted TME remodeling. EPB41L2low/ICGshigh patients showed greater benefit from immunotherapy. Gene mutation analysis revealed a close relationship between EPB41L2 and the frequency of oncogenic mutations, including TP53 and FGFR3.Comprehensive analysis and IHC confirmed the upregulation of EPB41L2 in BLCA CAFs and its association with TME remodeling. EPB41L2 and ICG expression were identified as combinatorial biomarkers to predict the response to immunotherapy.