Synergic effects of genetic polymorphisms related to estrogen and reproductive factors on breast cancer risk

Objective To determine whether there were synergic effects of increasing risk of breast cancer in Chinese women between the genetic poly mo rphisms of CYP 1A1 M spI,ERA PvuI I,XbaI and reproductive factors or not.Methods The study subjects were a subset of a population-based case-control study conducted in Shanghai between Jan 1,1999 and Apr 30,20011 PCR restrictive length fragment poly mo rphism(PCR-RFLP)method was used to examine the 3 candidate polymorphisms in DNA extracted from buccal cell in 282 breast cancer cases and 298 age frequency-matched controls.Multivariate Log istic model was used to estimate the OR and 95%CI for the group who were both with reproductive factors and with change of one of the candidate genetic polymorphisms.The synergic effects(additive model)between the reproductive factors and one of 3 candidate genetic polymorphisms were estimated by Rothman's method.Results There was a statistically significant positive additive synergic effect of increasing the breast cancerrisk(OR=5.66,95%CI:3.28-9.76,S=2.05,AP=0.42,u=1.982,P<0.05)bet ween the benign breast disease history and CYP/A/M spI polymorphism.No significant additive synergic effects were observed between the 3 candidate polymorphisms and other reproductive factors.Conclusion Probably,there were additive synergic effects of increasing breast cancer risk between the benign breast disease history and CYP1A1 M spI polymorphism.