Cytochrome P4501A1 gene polymorphism and homozygous deletion of the glutathione S-transferase M1 gene in urothelial cancer patients.

Japanese urothelial (bladder, renal pelvis and ureter) cancer patients (n = 83) and community controls (n = 101) were compared for rates of polymorphism in exon 7 of the cytochrome P4501A1 (CYP1A1) gene or homozygous deletion of the glutathione S-transferase class mu (GSTM1) gene. A CYP1A1 polymorphism was detected in a HinCII polymorphism assay utilizing a primer with a single base pair mismatch. The frequency distribution of the CYP1A1 genotypes in urothelial cancer patients showed no significant difference from that in healthy controls. The increased frequency of homozygous deletions of GSTM1 gene loci in patients with urothelial cancer was statistically significant compared with the controls, 51 of 83 (61%) and 43 of 101 (43%) (odds ratio = .2.15, 95% confidence interval = 1.18-3.86). These results lead us to conclude that homozygous deletion of the GSTM1 gene may be associated with susceptibility to urothelial cancer.