NDRG1 and urinary bladder carcinoma: Interestingly, our study is the first report which revealed that GDF15 blocked the effect of TGFβ/Smad signaling on the maspin and NDRG1 expressions in bladder carcinoma cells although GDF15 did not affect the phosphorylation of Smad 2/3 and Smad 1/5 in bladder carcinoma cells (Figure 3).