HMGB1 and urinary bladder cancer: To investigate the role of HMGB1 in bladder cancer cell's response to GEM, we examined the effect of HMGB1 knockdown on GEM-induced cytotoxicity (Figure 4A), which was associated with increased apoptosis that was detected as increased caspase-3 and PARP cleavage detected by Western blot and Annexin-V positive staining detected by flow cytometry assay (Figure 4B–4D).