| Part I Polymorphisms of P53, USP7and TSPYL5Gene and the Breast Cancer SusceptibilityObjective The tumor suppressor P53pathway plays a crucial role in DNA repair, apoptosis, cell cycle regulation. The polymorphisms of some genes in this pathway are associated with cancer susceptibility, and some clinico-pathological variables in kinds of cancers. It was reported that activity of P53was regulated by USP7(Ubiquitin Specific Peptidase7) and TSPYL5(Testis-specific Y-encoded-like protein5). This study was carried out to assess the association between single nucleotide polymorphisms (SNPs) in P53, USP7and TSPYL5gene and the breast cancer susceptibility in Chinese Han women.Methods We carried out this study with blood samples of192breast cancer patients and192age-matched control women. DNA was extracted from these blood samples. With Hapmap database and Haploview program, tag single nucleotide polymorphisms of P53, USP7and TSPYL5genes were selected. Then, the matrix-assisted laser desorption/ionization time-of-flight mass spectrometry assay was used for single nucleotide polymorphisms genotyping.Results There was no difference between breast cancer cases and matched controls in terms of age and menopause status (P=0.926,0.610, respectively).Hardy-Weinberg equilibrium of each polymorphism in the control group was tested, P value ranged from0.082to0.915. Genotype of SNP rs12924995and rs2304467in USP7gene was different in these two groups,(P=0.026,0.037, respectively). However, results of other SNPs in P53, USP7, TSPYL5gene were negative.Conclusion In this part, we detected more than20SNPs in3genes, and the results demonstrated that rs12924995and rs2304467in USP7gene might be associated with breast cancer susceptibility in Chinese women. It was the foundation of a case-control study with more samples in the next part. Part Ⅱ Case-control Study on the Association between rs2304467, rs12924995Polymorphisms in USP7Gene and Breast Cancer SusceptibilityObjective Based on the results of the first part, further case-control study with larger sample was to evaluate the association between rs2304467, rs12924995in USP7gene and breast cancer susceptibility in Chinese Han women.Methods DNA was extracted from the available peripheral blood samples of breast cancer patients and age matched controls. Genotype of rs2304467and rsl2924995was determinated by polymerase chain reaction-restricted fragment length polymorphisms assay (PCR-RFLP). Data of breast cancer cases including age of menarche, history of pregnancy and birth, pathological type, TNM stage, estrogen receptor, progesterone receptor and so on, was collected from medical records.Results975breast cancer patients and910controls enrolled in this study. Hardy-Weinberg equilibrium in the control group was tested (P=0.979,0.111). Multivariate analysis showed that the breast cancer risk of rs2304467CC carriers was the same as it of the rs2304467CG carriers (rs2304467CG:P=0.679. odds ratio (OR)=0.95,95%confidence interval (CI):0.74.1.21), and different from the risk of women with GG genotype (rs2304467GG:PO.001, OR=0.51,95%C1:0.36,0.73). Compared with rs2304467GG carriers, breast cancer risk of women with CC and CG genotype increased (P<0.001, OR=1.87,95%C1:1.44.2.44). There was no difference in rs12924995AA, CC and AC (P=0.074.0.992. respectively). However, women with rsl2924995AA and AC had higher risk of breast cancer than those with CC genotype (P=0.002, OR=1.36,95%CI:1.21-1.65). Conclusion Women with genotype rs2304467CC and CG, with rs12924995AA and AC, have higher risk of breast cancer than others in Han Chinese. Part III Peripheral Blood Mitochondrial DNA Content, Mitochondrial DNA A10398G Polymorphism and Breast Cancer SusceptibilityObjective It has been reported that P53pathway plays an important in repairing mitochondrial DNA (mtDNA) and regulating mitochondrial function. Mitochondrial DNA is more easily damaged than nuclear DNA, and quantitative alterations, sequence variations of mitochondrial DNA are associated with kinds of tumors’onset and progression. However, the relations of content, certain polymorphisms of mtDNA in peripheral blood leukocytes (PBLs) and breast cancer risk remain obscure. This study was undertaken to investigate whether mtDNA content and A10398G polymorphism in PBLs could be used as risk predictor for breast cancer in Chinese Han women.Methods Blood samples were obtained from a total of506breast cancer patients and520matched healthy controls. The mtDNA content was measured by using quantitative real-time polymerase chain reaction assay; A10398G polymorphism was determined by polymerase chain reaction restriction fragment length polymorphism assay.Results There was no statistically significant difference between cases and controls in terms of peripheral blood mtDNA content and A10398G polymorphism. However, further analysis suggested that the risk of breast cancer was associated with decreased mtDNA content in premenopausal women (P=0.001, high mtDNA content: OR=0.54,95%CI:0.38,0.77), with increased mtDNA content in postmenopausal women (P=0.027, high mtDNA content:OR=1.49,95%CI:1.05,2.11). In addition, the associations between mtDNA content and several clinicopathological parameters of cases such as age, menopausal status, number of pregnancies and live births were observed (P﹤0.001,0.006,0.001,﹤O.001. respectively). However, no modulating effect of age, menopausal status or mtDNA content on A10398G genotype distribution in cases and controls was identified (the Pvalue ranged from0.396to0.906). Besides, the distribution of mtDNA10398A and10398G carriers was different in the subgroups of cases, but the differences were not significant (P values ranged from0.052to0.977), with the exception of the histological types and human epidermal growth factor receptor2(Her2) status subgroups (P=0.006,0.016). Results of analysis including mtDNA content and2SNPs of USP7gene suggested that. SNPs rs2304467, rs12924995did not affect the content of mtDNA. What’s more, results about breast cancer risk in subgroups according to these two factors obtained the most outstanding OR value (3.46,95%CI:1.61-7.39) in this study.Conclusions The present case-control study demonstrated that premenopausal women with abnormal decreased mtDNA content, and postmenopausal women with abnormal increased mtDNA content, have higher breast cancer risk than others in Han Chinese. MtDNA content and SNPs in USP7gene can be used as molecular predictors of breast cancer susceptibility. |
PDF Full Text Request