Ringuette et al determined the fibroblast differentiation into CAFs through transforming growth factor beta 1 (TGF‐β) via bladder cancer (BC) cells‐derived exosomes, suggesting exosomal TGF‐β can be considered as a novel molecular mechanism involved in CAF activation in tumor.38 This evidence concerns the gene TGFB1 and urinary bladder carcinoma.