Objective To systematically review the correlation between polymorphism of DNA methyltransferase 1(DNMT1) rs16999593 and the susceptibility of breast cancer. Methods Databases such as PubMed, EMbase, Web of Science, Chinese Biomedical Literature Database, CNKI, WanFang, and VIP database were searched from inception to Mar. 2017 to collect case-control studies on the correlation between DNMT1 rs16999593 C/T polymorphism and the susceptibility of breast cancer. Two reviewers independently identified the literatures according to inclusion and exclusion criterias, extracted data, and assessed the quality of the included studies. The meta-analysis was performed by using RevMan 5.3 software. Results A total of 5 studies involving 1 741 cases and 1 917 control subjects were included. The results of meta-analysis showed that, dominate model ［TT+TC vs. CC: OR=0.63, 95% CI was (0.30, 1.30), P=0.21］, homozygous model ［TT vs. CC: OR=1.01, 95% CI was (0.70, 1.47), P=0.95］, heterozygous model ［TC vs. CC: OR=0.44, 95% CI was (0.18, 1.04), P=0.06］, and additive model ［T vs. C: OR=1.29, 95% CI was (0.90, 1.86), P=0.16］ were not significantly related to breast cancer, but recessive gene model was related to breast cancer ［TT vs. TC+CC: OR=1.74, 95% CI was (1.01, 3.00), P=0.04］. Conclusion The current studies showed that, DNMT1 rs16999593 TT genotype decreases the susceptibility of breast cancer.
ObjectiveTo study the correlation between CYP1A1 MspI gene polymorphisms and the risk of breast cancer (BC) in Chinese population.MethodsThe case-control studies on the correlation between polymorphisms of CYP1A1 MspI and BC in Chinese population were electronically retrieved in online English database (PubMed and Web of Science) and Chinese database (Chinese National Knowledge Infrastructure, Wanfang, and VIP database) from the date of their establishment to December 31, 2018. Two reviewers completed literature screening according to the inclusion and exclusion criteria, data extraction, and methodological quality assessment of the included studies independently. Reman 5.3 software was used to meta-analysis.ResultsA total 14 case-control studies involving 3 372 cases and 3 510 controls were finally included. The meta-analysis results showed that the CYP1A1 MspI gene polymorphism was associated with BC in Chinese population. Dominant genetic model [OR=1.24, 95%CI was (0.98, 1.58), P=0.08] and heterozygote model [OR=1.11, 95%CI was (0.89, 1.39), P=0.37] had no association with BC in Chinese population, while recessive genetic model [OR=1.66, 95%CI was (1.28, 2.14), P=0.000 1], homozygote model [OR=1.76, 95%CI was (1.26, 2.45), P=0.000 9], and allele contrast genetic model [OR=1.30, 95%CI was (1.08, 1.56), P=0.005] increased the risk of BC in Chinese population.ConclusionIt is demonstrated that in Chinese population, CYP1A1 MspI gene polymorphisms related to the risk of BC, recessive genetic model, homozygote model, and allele contrast genetic model might be the risk factor for BC.