Objective: To study the relationship between smoking, a cytochrome P-450 gene polymorphism and the development of bladder cancer.
Patients and methods: The study comprised 126 patients with a diagnosis of bladder cancer from whom a full history was obtained. Genomic DNA was extracted from blood sampled from each patient and genotyping of the CYP2D6 locus, the gene responsible for debrisoquine hydroxylase activity, was performed using a polymerase chain-reaction technique.
Results: Of the 126 patients, 78% had a history of smoking. There was a relationship between the number of cigarettes smoked and the grade of the presenting bladder tumour; heavy smokers developed high-grade disease. There was a trend for those heterozygous at the CYP2D6 locus and with a history of smoking to develop more aggressive disease, but this trend did not reach statistical significance.
Conclusion: The link between smoking and bladder cancer was confirmed. Furthermore, the grade of the presenting tumour was related to the 'cigarette-years'. The CYP2D6 genotype may influence the type of bladder cancer that develops in smokers.