Purpose: Interleukin-1 beta (IL-1 beta), a pro-inflammatory cytokine, has been shown to influence breast cancer susceptibility. The relationship between its risk of breast cancer and IL-1 beta-C31T polymorphism has been demonstrated, but the results remain controversial. Therefore, our study aimed to investigate the correlation between the IL-1 beta-C31T gene polymorphism and susceptibility to breast cancer. Methods: The genotype frequencies of IL-1 beta-C31T polymorphism were compared between 204 breast cancer cases and 210 controls using polymerase chain reaction and restriction fragment length polymorphism techinques. Further multivariate binary logistic regression analyses were used to assess the association between IL-1 beta-C31T polymorphism and breast cancer risk. Results: The frequency of the T allele of IL-1 beta-C31T polymorphism in breast cancer cases was significantly higher than that in the controls (56.1% vs. 47.9%). The frequencies of genotypes CC, CT, and TT in the cases were 22.1%, 43.6%, and 34.3%, respectively, while in the control group they were 24.3%, 55.7%, and 20.0%, respectively. There was a significant difference between the prevalence of TT genotype in the 2 groups (adjusted odds ratio [OR], 2.06; 95% confidence interval [CI], 1.16-3.66; p = 0.014). Breast cancer risk increased in women with TT genotype, body mass index (BMI) >= 25 kg/m(2) (OR, 2.19; 95% CI, 1.09-4.36), late age at first birth (OR, 2.43; 95% CI, 1.29-4.56), postmenopausal status (OR, 3.15; 95% CI, 1.39-7.16), and negative smoking history (OR, 2.52; 95% CI, 1.32-4.82). Furthermore, increase in breast cancer risk among women diagnosed with invasive ductal carcinoma was associated with CT/TT genotypes (OR, 2.82; 95% CI, 1.38-5.76). Conclusion: The IL-1 beta-C31T polymorphism affects breast cancer susceptibility, especially in women with late age at first birth, high BMI, postmenopausal status, negative smoking history, and invasive ductal carcinoma. Our study adds to the evidence about the importance of IL-1 beta-C31T polymorphism in breast cancer susceptibility.
