摘要
<p><b>OBJECTIVE</b>To investigate the relationship between polymorphisms of genes (CYP17, CYP19 and SULT1A1) involved in estrogen metabolism and susceptibility to breast cancer in Chinese women.</p><p><b>METHODS</b>A case-control study was performed. PCR-base restriction fragment length polymorphism (PCR-RFLP) and short tandem repeat polymorphism (STRP) assays were used to detect the polymorphism distribution of CYP17, CYP19 and SULT1A1 in 213 breast cancer cases and 430 matched controls. Logistic regression analyses were used to determine the OR, multivariate adjusted OR and 95% CI of each and all three genes and estrogen exposure factors on the risk of breast cancer. Relationship between polymorphisms and clinic-pathological features was also assessed.</p><p><b>RESULTS</b>The frequency of A2 allele of CYP17 was 49.8% in cases and 49.1% in controls (P > 0.05). The frequency His allele of SULT1A1 in cases (13.6%) was significant higher than that of controls (9.5%) (P = 0.03). There was also significant difference in the frequencies of (TTTA)10 allele CYP19 which was 12.4% in cases and 8.2% in controls (P = 0.02). Multigenic model indicated that there was an increased risk of breast cancer with more numbers of high-risk genotypes in a dose-response effect (trend P = 0.05). Data from multivariate analysis showed that the allele of SULT1A1 His and CYP19 (TTTA)10 was positively associated with the risk of breast cancer. Other well-established risk factors as higher estrogen exposure including total years of menstrual, early menarche etc, and women with a higher BMI and WHR were all served as independent risks.</p><p><b>CONCLUSION</b>This study indicated that the polymorphisms of estrogen-metabolizing genes were related to breast cancer.</p>
Subject(s)
Female , Humans , Aromatase , Genetics , Arylsulfotransferase , Genetics , Breast Neoplasms , Genetics , Case-Control Studies , China , Genetic Predisposition to Disease , Polymerase Chain Reaction , Polymorphism, Restriction Fragment Length , Steroid 17-alpha-Hydroxylase , Genetics摘要
<p><b>BACKGROUND</b>Endogenous estrogen plays a very important role in the carcinogenesis and progression of breast cancer. The enzymes involved in the biosynthesis and metabolism of estrogen have been proposed to contribute to this effect. To examine this hypothesis, we conducted a case-control study to investigate the relationship between polymorphisms of genes responsible for estrogen biosynthesis (CYP17, cytochrome P450c17a and CYP19, aromatase cytochrome P450) and estrogen sulfation of inactivation (SULT1A1, sulfotransferase1A1) and the risk of breast cancer in Chinese women.</p><p><b>METHODS</b>This study involved 213 breast cancer patients and 430 matched controls. PCR-based restriction fragment length polymorphism (RFLP) and short tandem repeat polymorphism (STRP) assays were used to detect the mononucleotide transition of CYP17 and SULT1A1 and tandem repeat polymorphism of CYP19. Logistic regression analyses were used to determine OR and 95% CI of each and all three high-risk genotypes, of all three genotypes combined, and of estrogen exposure factors. The relationship between each high-risk genotype and clinicalpathological characteristics were also assessed.</p><p><b>RESULTS</b>The frequency of A2 allele of CYP17 was 49.8% in cases and 49.1% in controls (P = 0.82). The frequency of His allele of SULT1A1 was significantly higher in cases (13.6%) than in controls (9.5%) (P < 0.05). There was also significant difference of the (TTTA) 10 allele of CYP19 which was 12.4% in cases and 8.2% in controls (P < 0.05). When the CYP17 A2 allele, CYP19 (TTTA) 10 and SULT1A1 His allele were considered as the "putative high-risk" genotype, there was an increased risk of breast cancer with the number of high-risk genotypes in a dose-response effect (trend, P = 0.05). In multivariate analysis, the SULT1A1 genotype remained the most significant determinant for breast cancer, with OR = 2.37 (95% CI 1.23-4.74), followed by CYP19, with OR = 1.75 (95% CI 1.27-3.56). The (TTTA) 10 allele of CYP19 was associated with tumor size, and the His allele of SULT1A1 associated with status of lymph node metastasis.</p><p><b>CONCLUSIONS</b>This study supports the hypothesis that breast cancer can be initiated by estrogen exposure and that estrogen metabolizing genes are involved in this mechanism. This multigenic model is useful for identifying individuals who are at higher risks of breast cancer.</p>