Mutations in DNA repair genes (XRCC3) and variants in genes coding for xenobiotic-transforming enzymes (NAT2, GSTM1, GSTP1 and NQO1) have been shown to modify the susceptibility to bladder cancer (Chao et al, 2006; Chaturvedi et al, 2007; Easton et al, 2007; Figueroa et al, 2007; Kellen et al, 2007; Sanderson et al, 2007; Murta-Nascimento et al, 2007b). This evidence concerns the gene GSTM1 and urinary bladder carcinoma.