GDF15 and urinary bladder carcinoma: Since F-actin polarization is the key factor to cell migration34, our immunofluoresence stain found that GDF15-knockdown enhanced the staining intensity of F-actin at the leading edge in HT1376 cells suggesting that GDF15 decreases cell invasion may via the downregualtion of EMT and F-actin polarization in bladder carcinoma cells.