Effects of Two Common Promoter Polymorphisms of Transforming Growth Factor-β1 on Breast Cancer Risks in Ahvaz, West South of Iran

BACKGROUND: Transforming growth factor-β1 (TGF-β1) has a critical role in breast cancer initiation and progression. OBJECTIVES: We have investigated the possible differences in two promoter polymorphisms (-509C/T and -800G/A) of TGF-β1 gene between breast cancer cases and controls. PATIENTS AND METHODS: A total of 100 patients with confirmed breast cancer and 100 subjects without breast cancer was selected. Two promoter polymorphisms (-509C/T and -800G/A) of TGF-β1 gene were genotyped using PCR-based restriction fragment length polymorphism (RFLP) method. RESULTS: The allele frequencies were 63% for C allele and 37% for T allele of SNP -509C/T and 66% for G allele and 34% for A allele of SNP -800G/A. Although no significant difference has observed between two groups, according to the genotype distribution, However, the TT genotype of -509 and AA genotype of -800 was significantly associated with breast cancer risk [odds ratio (OR) = 2.409; 95% confidence interval (CI) = 1.087 - 5.337, P = 0.030; and OR = 2.383; CI = 1.039 - 5.40, P = 0.040, respectively]. In addition, a multinomial logistic regression model shown, homozygous of -800 G/A (OR = 0.570; 95% CI = 0.362 - 0.896, P = 0.015); and HDL-C (OR = 0.935; 95% CI = 0.906 - 0.965, P < 0.001) were the selected variables associated with the presence of breast cancer. Haplotype analysis has shown no significant association between TGF-β1 haplotypes and breast cancer risk. CONCLUSIONS: Our results indicated that among two promoter polymorphisms of the TGF-β1gene, -800G/A compared to -509C/T is more associated with breast cancer.