SNP309 in MDM2 gene may be not associated with susceptibility of early-onset breast cancer:report from Fujian province

Background and purpose:SNP309,in the promoter region of the MDM2 gene,has been shown to increase MDM2 expression,as well as inhibit p53 function.Some studies have investigated the potential association of SNP309 with the susceptibility of breast cancer,but with conflicting results.The present case-control study explored the effect of SNP309(TG) polymorphism(rs2279744) in the MDM2 gene on the genetic susceptibility of early-onset breast cancer.Methods:One hundred and twenty three early-onset breast cancer patients(age≤35 years at diagnosis) from independent families and 101 age-matched healthy control subjects were analyzed.Genotype analysis was conducted using polymerase chain reaction(PCR) and MALDI-TOF-MS assay.The odd-ratios(OR) and 95% confidence intervals(CI) were calculated using the unconditional logistic regression model.Results:The frequency of rs2279744 polymorphism genotypes in the controls and case groups were TT:28(27.7%)/26(21.1%),TG:50(49.5%)/61(49.6%),GG:23(22.8%)/36(29.3%),respectively,which were not significantly different(P0.05) according to the chi-square test.Under logistical regression analysis,rs2279744 GT or GG genotype did not confer a significantly increased risk for breast cancer as compared with the rs2279744 TT genotype with OR=1.358(95%CI:0.706-2.614)(P0.05).Conclusion:Based on our findings,it is suggested that SNP309(TG) polymorphism in the MDM2 gene may not confer risk to breast cancer,especially for early-onset breast cancer patients.Further investigation is necessary to confirm SNP309 as a candidate for low-penetrance breast cancer susceptibility.