Association of interleukin-1Ra gene polymorphism in patients with bladder cancer: case control study from North India.

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.