It was confirmed that miR-5195-3p inhibited the proliferation and invasion of bladder cancer cells by targeting the oncogene KLF5.21 and inhibited the activity of HCT116 cells by inhibiting the expression of TGFβR1, TGFβR2, SMAD3 and SMAD4 [26]. Here, SMAD4 is linked to urinary bladder cancer.