Synuclein-γ Polymorphisms and radiotherapy for breast cancer: a retrospective study

Background: Synuclein γ (SNCG), a member of the brain protein synuclein family, is highly expressed in pervasive human breast carcinoma and was associated with poor outcomes in radiotherapy treatment. So, the present study was conducted to assess the C243G and A377T polymorphisms of this gene in relationship with the success of radiotherapy. Materials and Methods: In this retrospective study, 114 patients who had undergone a radical modified mastectomy and referred for radiation therapy were studied. Genomic DNA was extracted from peripheral blood cells. Genotyping was done for C243G and A377T polymorphisms. Differences in allele or genotype frequencies were evaluated. Results: The median overall Survival (OS) Rate of all patients was 44 months (IQR: 5.09). Genotyping the patients, there were 25 (%) GG, 34 (%) CG, and 55 (%) CC patients for exon 3 polymorphism (C243G). Comparison of three genotypes effect on OS was not significant (X2 (2) =2.25, P=0.323). Hazard Ratio of CC vs. GG was 1.042 (95%CI:0.5360- 2.027), which was not statistically significant. There were 60 (%) AA, 37 (%) AT, and 17 (%) TT patients for exon 4 polymorphism (A377T). Comparison of three genotypes effect on OS was not significant (X2(2) =0.441, P=0.802). Comparing only patients with AA and TT genotypes, Hazard Ratio of AA vs. TT was 1.26 (95%CI:0.5123-3.118), which was not statistically significant. Conclusion: There is a possibility of the role of GG and TT genotypes as a genetic risk factor in breast cancer which should be evaluated in a study with higher sample size.