DDR2 and bladder transitional cell carcinoma: Single-cell RNA-seq and IHC confirmed CAF-specific overexpression of DDR2 and SERPINF1.<h4>Conclusion</h4>The MBRG-based model effectively predicts BLCA prognosis, integrates mechanisms of basement membrane remodeling, EMT, and immune suppression, and identifies DDR2 and SERPINF1 in CAFs as potential targets for personalized therapy.