Previous studies have shown that decreased expression of epithelial markers E-cadherin and β-catenin is associated with bladder cancer progression,24, 30 and E-cadherin is reduced or absent in >80% of MIBCs.28 Thus we wanted to determine whether E-cadherin and β-catenin were downregulated in the primary urothelial cells treated with MIBC exosomes. This evidence concerns the gene CDH1 and urinary bladder cancer.