FAS and urinary bladder carcinoma: To determine whether Fas/Fasl and TNF-α/TNFR1 expression is critical for the effect of HCS on bladder cancer cells, we knocked down TNF-a, TNFR1, Fas by siRNA or inhibited binding of FasL to its receptor by a blocking antibody (ZB4) prior to the addition of HCS, and then detected the cell viability.