| Objective: Endometriosis is defined as the presence of endometrial tissue outside the uterus. Adenomyosis is also a common disease in women of reproductive age and regresses after menopause, characterized histologically by the presence of functional endometrial glands and stroma within the myometrial wall of the uterus. As common diseases of child-bearing period women, the aetiology and pathogenesis are still unclear. Although the two diseases are nonmalignant disorder, the ectopic endometrium has the capacity to adhere, attach, and implant. Like the occurrence of tumor, angiogenesis is a prerequisite for the development of endometriotic lesion. Vascular endothelial growth factor (VEGF) is one of the powerful factors to facilitate angiogenesis as we know so far. Previous studies indicated that ectopic endometrium from patients with endometriosis or adenomyosis expressed higher levels of VEGF than healthy controls. These findings suggested that VEGF might play a critical role in the development of endometriosis and adenomyosis. At least 30 single nucleotide polymorphisms (SNPs) exist in the VEGF gene. Among them, the two VEGF polymorphisms (-2578C/A and +936C/T) have been reported to affect the expression of the gene and indicated to be involved in the development of diseases. In the present case-control study, we investigated the relationship between genetic polymorphisms in the VEGF gene and the development of endometriosis and adenomyosis in North Chinese Women.Methods: This case-control study comprised 344 women with endometriosis and 360 frequency-matched healthy control women, 174 women with adenomyosis and 199 control women with no evidence of disease. Five milliliter of venous blood from each subject was drawn in Vacutainer tubes containing EDTA and stored at 4℃, while the information of every subject was obtained. The genomic DNA was extracted within one week after bleeding by using proteinase K digestion followed by a salting out procedure. Genotypes of the VEGF -2578C/A and +936C/T SNPs were analyzed by polymerase chain reaction- restriction fragment length polymorphism (PCR-RFLP) method. Statistical analysis was performed using SPSS11.5 software package. A probability level of 5% was considered significant. The age difference of cases and frequency-matched controls was analyzed by the t-test. Hardy-Weinberg analysis was performed by comparing the observed and expected genotype frequencies in study groups using Chi-square test. Comparison of the genotype and allelotype distribution in patients and healthy controls was performed by means of two-sided contingency tables using Chi-square test. The odds ratio (OR) and 95% confidence Interval (CI) were calculated using an unconditional logistic regression model. The VEGF -2578C/A and +936C/T haplotype frequencies and linkage disequilibrium coefficient were estimated using the EH linkage software and 2LD program, respectively.Results: 1 No significant difference was found in allele frequencies and genotype distributions of VEGF +936C/T polymorphism between patients and control women (all P value >0.05). There were significant differences in allele frequencies and genotype distributions of the VEGF -2578C/A polymorphism between endometriosis patients and control women. The frequency of the C allele in endometriosis patients (80.8%) was significantly higher than that in the controls (73.8%) (χ2=9.97, P=0.002). The frequencies of the C/C, C/A and A/A genotypes in endometriosis patients (64.8%, 32.0% and 3.2%) were significantly different from those of controls (55.6%, 36.4% and 8.1%) (χ2=10.8, P=0.004). Compared with the A/A+C/A genotype, the C/C genotype could significantly increase the risk of endometriosis development. The OR was 1.47 (95%CI=1.09-2.00). 2 No significant difference was found in allele frequencies and genotype distributions of VEGF +936C/T polymorphism between patients and control women (all P value >0.05). There were significant differences in allele frequencies and genotype distributions of the VEGF -2578C/A polymorphism between adenomyosis patients and control women. The frequency of the C allele in adenomyosis patients (80.4%) was significantly higher than that in the controls (72.4%) (χ2=6.70, P=0.010). The frequencies of the C/C, C/A and A/A genotypes in patients (65.5%, 29.9% and 4.6%) were significantly different from those in the controls (54.8%, 35.2% and 10.0%) (χ2=6.26, P=0.044). Compared with the A/A+C/A genotype, the C/C genotype could significantly increase the risk of adenomyosis development. The OR was 1.57 (95%CI= 1.03-2.39). 3 The results of the 2LD program analysis showed that the VEGF -2578C/A and VEGF +936C/T polymorphisms did not display linkage disequilibrium.Conclusions:1 The VEGF +936C/T polymorphism might not be related to the risk of endometriosis and adenomyosis development.2 The VEGF -2578C/A polymorphism in the promoter region of VEGF gene was associated with the risk of developing endometriosis and adenomyosis in North Chinese Women. The subjects carrying C/C genotype could be associated with the increased risk of developing endometriosis and adenomyosis.3 The VEGF -2578C/A and VEGF +936C/T polymorphisms did not display linkage disequilibrium, D′=0.049. |
