Introduction: Breast-cancer is the most common cancer among women. FAS gene is crucial and important in the apoptotic pathway of cell death. Decreased expression of FAS gene and consequently de-regulation of proapoptotic signaling have been seen in various tumors such as breast-tumors. Single-nucleotide polymorphisms in the promoter of FAS gene such as G>A substitution at nucleotide position -1378 that is located within the Sp1 transcription-factor binding site, may influence FAS expression. This study investigated the association between FAS-1378G>A polymorphism and susceptibility to breast-cancer in northwestern Iran.

Materials & methods: This study was conducted on 170 breast-cancer patients and 154 healthy controls. Different genotypes of FAS-1378G>A were determined using Tetra-ARMS-PCR and direct DNA-sequencing and compared.

Findings: In the control-group, the genotype distribution of FAS polymorphism, showed 62.17%, 35.25%, 1.28% for GG, AG, AA genotypes, respectively. In the cancer-group, the distribution was 59.41%, 38.23% and 2.35% for GG, AG, AA genotypes, respectively. Distribution differences in the FAS-1378G>A polymorphism between the cases and controls were not statistically significant (p>0.05).

Discussion & conclusions: The present investigation is the first study in regard to the association of FAS-1378G>A polymorphism with breast-cancer risk in northwestern population of Iran. The results of this study showed that there were no significant differences in the genotype/allele distribution between cases and controls. These findings suggest that FAS-1378G>A polymorphism may contribute to breast cancer susceptibility in northwestern Iran. According to the results of this study, rs2234767 polymorphism can be as a marker for lymph-node involvement and age at diagnosis in the studied population.