SP3 and urinary bladder cancer: ROS and hydrogen peroxide (H2O2) play a role in downregulation of Sp1, Sp3 and Sp4 in pancreatic and bladder cancer cells [34,37] and treatment of RKO cells with BA for 36 h induced ROS as determined by FACS analysis using the fluorescent ROS scavenger H2DCFDA (Figure 4A).