Objectives: To evaluate whether polymorphism of interleukin (IL)-1beta gene (exon 5 and promoter region) and IL-1 receptor antagonist (Ra), 86-bp variable number tandem repeat, are associated with transitional cell carcinoma of the urinary bladder, because cytokines have been hypothesized to be important in cancer development.
Methods: The study included 120 patients with bladder cancer (age range 32 to 69 years) and 150 age-matched controls (age range 25 to 62 years). The polymorphisms were identified by polymerase chain reaction/restriction fragment length polymorphism method and IL-1Ra polymorphism by variable number of identical tandem repeat analysis. Genotype distribution and allelic frequencies between patients and controls were compared.
Results: A significant difference was found in the frequency distribution of the IL-1Ra gene polymorphism in patients with bladder cancer compared with the normal control group (P < 0.001), but no difference was found in the frequencies of the IL-1beta promoter region and exon 5 genotypes between patients with bladder cancer and controls (P = 0.112 and P = 0.953, respectively).
Conclusions: This is perhaps the first report on polymorphic changes in gene encoding IL-1Ra in patients with bladder cancer from India. Our data suggest that IL-1Ra intron 2 polymorphism seems to play a prominent role among the IL-1 gene cluster with respect to bladder cancer, and the association studies appear to be plausible in determining the cancer susceptibility and risk.