the study of dna methyltransferase-3b promoter variant genotype among iranian sporadic breast cancer patients

background: dna methyltransferase-3b (dnmt3b) is an important enzyme responsible for maintaining the dna methylation pattern in eukaryotic cells. in this study we have investigated the correlation between the 46359c→t polymorphism in the dnmt3b gene and the risk of breast cancer incidence among sporadic breast cancer patients in fars province, southern iran. methods: in this case-control study, 100 breast cancer patients and 138 healthy control subjects were genotyped for the dnmt3b gene by the polymerase chain reaction-restriction fragment length polymorphism method. results: the genotype frequency in the case (cc 27%, ct 47%, tt 26%) group significantly (p=0.008) differed from the control (cc 19.56%, ct 67.3%, tt 13%) group. we observed a decreased association between the ct genotype and lymph node involvement in breast cancer patients. our results have shown that in comparison to the homozygous cc genotype carriers the dnmt3b-ct genotype has a significantly lower risk for breast cancer (or=0.515, 95% ci=0.267-0.994, p=0.048). conclusion: our case-control study showed that the ct genotype was significantly associated with decreased breast cancer risk. consistent with these results, a significant decrease of ct genotype among lymph node positive breast cancer patients was observed. however, a larger study population with more clinical data is needed to confirm these results.