Association Between MUC4 Gene Polymorphism And Endometriosis

Research BackgroundEndometriosis(EMs)is a benign,estrogen-dependent chronic gynecological disease,and histologic feature of EMs is endometrial stroma and glands growing outside the uterus.EMs is often accompanied by infertility and dysmenorrhea.However,the pathogenesis responsible for this disease remains unclear.It is evident that EMs is related to genetic factors,and even accounting for half of the risk of developing EMs.Mucin(MUC)is a high-molecular-weight glycoprotein,which is almost expressed on the surface of all the simple epithelial tissues and various tumor cells to lubricate and protect them from pathogens and the environment.Among the MUC family,MUC4 is the one that get high level expression in the endometrial epithelial cells.As a membrane-bound protein,MUC4 can regulate cell apoptosis negatively through Erb B2 dependent and independent mechanisms.Abnormal expression of MUC4 is associated with many kinds of cancers,including ovarian cancer,colorectal cancer,lung cancer,pancreatic cancer and many other cancers,which has become a new target of cancer diagnosis and treatment.However,few investigations have been done with MUC4 gene polymorphism and EMs so far.There are only two small-scale studies conducted in the populations of Taiwan and South Korea,but the results were inconsistent.No relevant studies have been conducted in mainland China.In this study,we attempted to clarify the association between MUC4genetic variants and EMs in Han Chinese female of Henan nationality by genotyping the five(single nucleotide polymorphisms)SNPs loci of MUC4.Objective1.To investigate the association of MUC4 genetic(rs882605,rs1104760,rs2688513,rs2246901,and rs2259102)variants with the risk of EMs in Han Chinese female of Henan nationality.2.To investigate the association of rs882605,rs1104760,rs2688513,rs2246901and rs2259102 with clinical stage,CA125 level,dysmenorrhea and infertility in patients with EMs.MethodsWe performed a case-control study including 119 patients with endometriosis and 117 control group of women without endometriosis who were hospitalized in the Third Affiliated Hospital of Zhengzhou University from December 2018 to December2019(all Han Chinese from Henan).After obtaining the consent of the research subjects,clinical data of the patients were collected,and peripheral venous blood was collected to extract genomic DNA.The five SNPs in MUC4 were determined using a matrix assisted laser desorption ionisation-time of flight mass spectrometry(MALDI-TOF-MS).Evaluation of Hardy-Weinberg Equilibrium(HWE)byχ~2 test.The differences of allele and genotype distribution frequency of groups were compared byχ~2 test,and the odds ratios(ORs)and 95%confidence intervals(CIs)were estimated using a logistic regression.Linkage disequilibrium(LD)and Haplotype frequency among SNPs were conducted using Haploview software.To confirm the effect of MUC4 SNPs on allele-specific transcriptional regulation and chromatin structure,we used Regulome D and Haplo Reg V4.Results1.Bioinformatics analysis showed that rs882605,rs1104760,rs2688513,rs2246901 and rs2259102 Regulome DB score were all less than 2.These five Loci are all missense mutation sites of MUC4 gene,and all of them may be potential expression quantitative trait locus(e QTL)and may be involved in regulating transcription factor binding and Deoxyribonuclease(DNase)peak.2.In the association analysis between MUC4 gene polymorphism and EMs susceptibility,we failed to find any statistically significant difference in the frequencies of allele of the four MUC4 SNPs among the endometriosis and the control group(P>0.05),nor the genotypes analysis under each logistic regression model(codominant,dominant and recessive)(P>0.05).rs2688513,rs1104760,and rs882605 exhibit extremely significant linkage disequilibrium(r~2=0.96).We further examined the effect of the haplotype“AAG”and“GGT”(rs882605、rs1104760、rs2688513)frequencies in the development of endometriosis.Similarly,no association with EMs risk was found(P>0.05).3.The association analysis between MUC4 gene polymorphism and EMS clinical characteristics showed that C allele of rs2246901 genetic variations was found to be related to the severity of endometriosis(adjusted OR=3.1720,95%CI:1.20-8.56,P=0.020).On the other hand,after adjustment for age and BMI,the results of recessive model indicated that TT genotype of rs882605 reduced the risk of moderate to severe dysmenorrhea by 80%compared with GG+GT(OR=0.20,95%CI:0.04～0.83,P=0.027),the rs1104760 GG genotype was also a protective factor for the occurrence of moderate to severe dysmenorrhea(OR=0.20,95%CI:0.04～0.83,P=0.027).In addition,the rs2688513 G allele has half the risk of infertility as the A allele(OR=0.50,95%CI:0.25～0.98,P=0.046).In the dominant models,after adjustment for age and BMI,the frequency of the GG genotype of rs882605,the AA genotype of rs1104760,and the AA genotype of rs2688513 were higher in infertility group(All P<0.05).However,no statistically significant differences were found in allelic or genotype frequencies of five SNPs in the high CA125 group and the low CA125 group in EMs patients.Conclusions1.MUC4 genetic variants maybe do not have impact on endometriosis susceptibility but were associated with severe endometriosis in Han Chinese female of Henan nationality.2.MUC4 rs1104760,and rs882605 may confer a protective effect on endometriosis-related dysmenorrhea(moderate to severe),while rs2688513,rs1104760,and rs882605 also involved in endometriosis-related infertility,however,the SNPs were not associated with CA125 levels in EMs women.