Although early studies indicated that arsenic-induced metal-responsive transcription factor-1 (MTF-1) binds to the metal-response element (MRE) of the promoter MT3 and NDRG1 genes [18,31], the molecular mechanisms of arsenic on gene expressions of MT3 and NDRG1 in bladder carcinoma cells are still undefined. This evidence concerns the gene MTF1 and urinary bladder carcinoma.