Relationship Between Endometriosis And Polymorphisms Of CYP19 Gene

Objective: Endometriosis(EMs) is one of the most common gynecological disorders of reproductive aged women. The incidence reaches 10%-15%,and the tendency has being evaluated in recent years.This disease can bring chonic pelvic pain and infertility for women.Although there are various etiogenic theories,the etiology and pathogenesis of endometriosis is remain obscure. It is widely accepted that endometriosis is a multifactorial disease and caused by a possible genetic predisposition and hormonal status. Cyclical variation with hormone is the feature of endometrium. The growth of endometriosis is stimulated by local enstrogen production in conjunction with circulating estrogen.Recent studies have considered EMs as an enstrogen-dependent disease . Aromatase is a member of the cytochrome P450 enzyme family and is encoded by the CYP19 gene. Aromatase is one of the essential enzymes for the biosynthesis of estrogen,which converts androgens into estrogens, androstenedione into estrone, and testosterone into estradiol. Although endometriotic implants express aromatase, endometrial tissue from uterine-disease-free women does not exhibit aromatase activity . We speculated that the onset or growth of endometriosis might be associated with the single nuleotide polymorphism (SNPs) of CYP19.Currently CYP19 gene polymorphism are reportedly associated with strogen-dependent diseases,such as breast cancer, endometrial cancer, Osteoporosis, uterine myoma and endometriosis.The CYP19 gene has several polymorphisms: codon 39(Trp-Arg),codon264(Arg-Cys),408(silencer),[TTTA]n tetranucleotide repeat polymorphism inintron 4 andinsert / deletion polymorphism.We evaluated whether the 115T>C,240G>A, and 1531C>T polymorphisms and their haplotypes polymorphisms in CYP19 are associated with the risk of moderate/severe endometriosis.Methods: Group of patients with endometriosis: A total 102 women between 22 and 45 years old undergoing laparotomy or laparoscopy for endometriosis in the Department of Obstetrics and Gynecology of the Second Affiliated Hospital of Hebei Medical University. Diagnosis of endometriosis was establishied laparoscopically and histologically. In clinical practice, most women with minimal/mild endometriosis accept conservative medication instead of invasive management. Therefore, we only recruited the moderate/severe endometriosis women for the survey. Control group: 100 women were from non-endometriosis patients who were such conditions as reananstomosis infertility or ovarian dysembryoma or simple cyst, and without pelvic endometriosis and adenomyosis and adenomyosis evidenced by laparotomy or laparoscopy, with no history of endometriosis. All patients didn't take any drugs with hormone or immune suppression . The genomic DNA was prepared from peripheral blood leukocytes by the use of a genomic DNA isolation kit. The DNA was stored at -80oC until analyzed. CYP19 115 T/C,240 A/G and 1531 C/T fragment was amplified by polymerase chain reaction (PCR). After PCR amplification, the PCR products were digested at 37℃with different restriction enzyme to detect CYP19 240 A/G and 1531 C/T allele, then subjected to 3% agarose gel electrophoresis and visualized under ultraviolet light. Statistical analysis was performed using SPSS13.0 software package. Two-tailed test with P<0.05 were considered significant.Results:1 Hardy-Weinberg analysis was performed to compare the observed and expected genotype frequencies using Chi-square test, finally shows P>0.05, indicated in choosing the community the candidate gene has reached the heredity balance.2 Among 102 patients with stageⅢ,Ⅳendometriosis and100 controls,proportions of CYP19 115T/homozygote/ heterozygote/C homozygote in the group of endometriosis were: 91.18/8.82/0% , and in the control group were 88/11/1%, respectively(χ~2=0.547,P=0.46 ) .No association between CYP19 115 T/C polymorphisms andⅢ,Ⅳendometriosis was found. The percentage of CYP19 115 T/C alleles in both groups were 95.60/4.41% and 93.5/6.5%, respectively(χ~2=0.855,P=0.355). OR=1.409 ( 95%CI 0.566- 3.508).No differences was also found between the two groups. This indicated that CYP19 115 T/C gene polymorphism may not be an independent risk factor in endometriosis development.3 Among 102 patients with stageⅢ,Ⅳendometriosis and100 controls, proportions of CYP19 A /homozygote/heterozygote/G homozygote were:27.54/50.92 /23.53%, and 45/41/14%, respectively (χ~2=7.462,P=0.024). Statistic analysis suggested CYP19 240A/G genotype polymorphism icreases risk ofⅢ,Ⅳendometriosis. The percentage of CYP19 240A/G alleles in both groups were 51.96/48.04% and 65.5/34.5%, respectively (χ~2=7.634, P=0.006). OR= 2.162 ( 95%CI 1.203-3.888 ) .A statistic differences was found between the two groups. Statistic analysis suggested CYP19 240G-related genotypes and alleles are associated with higher susceptibility to endometriosis. CYP19 240A/G gene polymorphisms might be associated withⅢ,Ⅳendometriosis development.4 Among 102 patients with stageⅢ,Ⅳendometriosis and100 controls, proportions of CYP19 1531 C/ homozygote/ heterozygote/T homozygote in the group of endometriosis were: 41.18/47.06/12.71% , and in the control group were 38/42/20%, respectively(χ~2=2.580,P=0.275 ) .No association between CYP19 1531 C/T polymorphisms andⅢ,Ⅳendometriosis was found. The percentage of CYP19 1531 C/T alleles in both groups were 64.71/35.30% and 59/41%, respectively(χ~2=1.394,P=0.238). OR=0.876 ( 95%CI 0.498- 1.540).No differences was also found between the two groups. This indicated that CYP19 1531 C/T gene polymorphism may not be an independent risk factor in endometriosis development.Conclusion: 1 These results suggest that CYP19 240A/G polymorphism may contribute to the genetic influence on stageⅢ,Ⅳendometriosis. 2 There was no association between CYP19 115 C/T and CYP19 1531 T/C polymorphism and stageⅢ,Ⅳendometriosis.