Tehran University of Medical Sciences Basic & Clinical Cancer Research 2228-6527 11 2 2019 05 09 84 89 Ali Akbar Amirzargar Molecular Immunology Research Center and Department of Immunology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran. Maryam Sadr Molecular Immunology Research Center and Department of Immunology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran. Samira Esmaeili Reykande Molecular Immunology Research Center and Department of Immunology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran Elham Mohebbi Cancer Research Center, Cancer Institute of Iran, Tehran University of Medical Sciences. Tehran, Iran. Mohammad Shirkhoda Cancer Research Center, Cancer Institute of Iran, Tehran University of Medical Sciences. Tehran, Iran Majid Mahmoodi Cancer Research Center, Cancer Institute of Iran, Tehran University of Medical Sciences. Tehran, Iran 2019 01 16 2019 02 12 Background: Estrogen is a risk factor for the development of breast cancer. The effect of estrogen is primarily mediated by estrogen receptor alpha 1 (ESR1). In this study, we investigated the association between breast cancer risk and the frequency of alleles and genotypes for two ESR1 single nucleotide polymorphisms (SNPs) in breast cancer patients and a healthy control group.      Methods: A total of 98 female patients with pathologically confirmed breast cancer and 93 age-matched healthy female controls who were selected from among the visitors of the general hospital were recruited in the study. Two ESR1 candidate polymorphisms; +2464 C/T (rs3020314) and -4576A/C (rs1514348) were selected. The frequency of alleles and genotypes was determined using Quantitative Real-Time PCR assay. Linkage disequilibrium (LD) was assessed for each pair of markers. Using logistic regression, genotype frequencies were estimated as Odds Ratios with 95% confidence intervals. Results: There was no significant difference in the genotype and allele distributions of ESR1 for SNPs +2464 C/T and SNP -4576A/C between patients and controls. The frequency of the ESR1 +2464 T/T genotype in case and control groups was 31.6% vs 29.0%, (OR TT/TC: 1.13, 95%CI: 0.58, 2.20; P = 0.69). The frequency of the +2464C allele was 33.9% vs 35.2%, (OR C/T: 0.94, 95%CI: 0.60, 1.47; P =0.79). The frequency of the ESR1 -4576C/C genotype in case and control groups was 37.75% vs 33.36 %, OR CC/AC: 1.02, 95%CI: 0.51, 1.97; P =0.98). The frequency of the -4576A allele was 36.2% vs 43.6 %, (OR C/A: 0.73, 95%CI: 0.47, 1.13; P =0.14). Conclusion: The results indicated that ESR1 polymorphism does not show any significant association with breast cancer risk among female Iranian adults. https://bccr.tums.ac.ir/index.php/bccrj/article/view/312