{"paper_id":"557face2-84b7-4652-9d71-6ef042bde05d","body_text":"R E S E A R C H A R T I C L E Open Access\nMUC2 polymorphisms are associated with\nendometriosis development and infertility:\na case-control study\nCherry Yin-Yi Chang 1,2†, Yi Chen 3†, Wu-Chou Lin 1, Chih-Mei Chen 3, Chih-Ping Chen 4, Shan-Chih Lee 5,\nJim Jinn-Chyuan Sheu 3,6,7* and Fuu-Jen Tsai 3,8*\nAbstract\nBackground: Mucins are highly glycosylated proteins protecting and lubricating epithelial surface of respiratory,\ngastrointestinal and reproductive tracts. Members of the mucin protein family have been suggested to play an\nimportant role in development of endometriosis and infertility. This study investigates genetic association of\nmucin2 ( MUC2) with the risk of endometriosis and endometriosis-related infertility.\nMethods: This case-control study was conducted at China Medical University Hospital, with 195 endometriosis\npatients and 196 healthy controls enrolled. Genotyping of six SNPs (rs2856111, rs11245936, rs10794288, rs10902088,\nrs7103978 and rs11245954) within MUC2 gene were performed by using Taqman genotyping assay; individual SNP\nand haplotype associations with endometriosis and endometriosis-related infertility were assessed by c\n2 test.\nResults: Endometriosis patients exhibit significantly lower frequency of the rs10794288 C allele, the rs10902088 T\nallele and the rs7103978 G allele ( P = 0.030, 0.013 and 0.040, respectively). In addition, the rs10794288 C allele and\nthe rs10902088 T allele were also less abundant in patients with infertility versus fertile ones ( P = 0.015 and 0.024,\nrespectively). Haplotype analysis of the endometriosis associated SNPs in MUC2 also showed significantly\nassociation between the most common haplotypes and endometriosis or endometriosis-related infertility.\nConclusions: MUC2 polymorphisms, especially rs10794288 and rs10902088, are associated with endometriosis as\nwell as endometriosis-related infertility. Our data present MUC2 as a new candidate involved in development of\nendometriosis and related infertility in Taiwanese Han women.\nBackground\nEndometriosis is a common chronic gynecologic disease\ndefined as presence of endometrial tissue outside the\nuterine cavity, primarily on pelvic peritoneum and\novary. Epidemiology studies reveal that endometriosis\naffects more than 10% of reproductive age women and\npossibly causes infertility [1,2]. The prevalence of endo-\nmetriosis was 0.5-5% in fertile and 25-45% in infertile\nwomen [3]. The mechanism underlying endometriosis\ndevelopment remains unclear, even though theories like\nimplantation, altered immuni ty, and susceptible genetic\nfactors have been proposed to explain the pathogenesis\n[4-6]. Nevertheless, familial and identical twins studies\nhave established the genetic predisposition to endome-\ntriosis development [7].\nClinical manifestation of endometriosis is accompa-\nnied by angiogenesis and formation of cellular adhesion\n[8,9], possibly due to altered peritoneal environment and\nimmune system [10]. In endometriosis patients, changes\nin levels of growth factors, cytokines and oncofetal anti-\ngens may facilitate intraperitoneal endometrial growth\nand alter the peritoneal environment, which leads to dis-\nruption of normal pelvic organ architectures and inferti-\nlity [8]. For instance, interluekin-1 (IL-1), interleukin-6\n(IL-6), interleukin-8 (IL-8), interleukin-10 (IL-10),\nnuclear factor- /C20B( N F -/C20B) and tumor necrosis factor-\nalpha (TNF- a) are among the major cytokines partici-\npating in regulation of immune system, angiogenesis,\n* Correspondence: jimsheu@mail.cmu.edu.tw; d0704@mail.cmuh.org.tw\n† Contributed equally\n3Human Genetics Center, China Medical University Hospital, 2 Yude Road,\n40447 Taichung, Taiwan\nFull list of author information is available at the end of the article\nChang et al . BMC Medical Genetics 2012, 13:15\nhttp://www.biomedcentral.com/1471-2350/13/15\n© 2012 Chang et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons\nAttribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in\nany medium, provided the original work is properly cited.\n\ncell proliferation and tissue invasiveness during the for-\nmation of endometriosis [11-14].\nMucins are high molecular weight glycoproteins with\nfunction of protecting and lubricating epithelial surface\nof respiratory, gastrointest inal and reproductive tracts\n[15]. Mucins are also found to be expressed on activated\nlymphocytes, supporting the hypothesis that some\nmucin domains function as cytokines to mediate\nimmune responses [16,17]. Early studies reported that\nmucin played important role in the progress of tumor\ninvasion, which is influenced by their glycosylation sta-\ntus [15,18-20]. More recently, mucin1 (MUC1) has been\nreported to be linked to endometriosis and infertility\n[21,22], and mucin4 (MUC4 ) gene polymorphisms were\nproved to be associated with endometriosis development\nas well [23]. The human mucin2 ( MUC2 )g e n ei s\nlocated on chromosome 11p15.5, encoding one of the\nmost common gel-forming secreted type of mucin [24].\nMUC2 expression was reported to be regulated by many\nendometriosis-related cytokines, such as IL-1 b,I L - 6 ,\nTNF- a, NF-Kappa B [9,25-27]. Abnormal increase of\nmucin2 (MUC2) expression was reported to be linked\nto intestinal and uterine ce rvix metaplasia progression\n[28,29].\nHowever, there has been no study yet investigating the\nrelationship between endometriosis and MUC2, while\nprevious functional studies on MUC2 are more focused\non its role in the gastrointestinal and respiratory tract\n[30,31].\nThe aim of this study was to investigate the possible\nassociation of MUC2 gene polymorphisms with the risk\nof endometriosis and endometriosis-related clinical\nsymptoms in a Taiwanese population.\nMethods\nSubjects\nIn all, 195 patients receiving surgery for ovarian benign\ndisease and pathology-prov en endometriosis patients\nwere identified at China Medical University Hospital\nfrom 1998-2011 and enrolled in the study. They\naccepted examination of ultr asound before operation\nand were diagnosed with ovarian cysts; symptoms of\ndysmenorrhea, lower abdominal pain, infertility or\nabnormal menstruation were recorded for each patient.\nAnother 196 healthy controls were recruited from a\npool of persons who received regular health checkups at\nthe same hospital. People with ovarian cysts detected by\nultrasound or any symptoms of dysmenorrhea, lower\nabdominal pain, infertility, abnormal menstruation were\nexcluded from the controls. Both patients and controls\nshare similar age profile. Clinical information of patients\nwas collected from medical charts, including clinical\nstage, lesion size, location, drug treatment and fertility.\nThe definition of endometriosis staging was based on\ncriteria of the American Society for Reproductive Medi-\ncine: stage 1, minimal; stage 2, mild; stage 3, moderate;\nand stage 4, severe [32]. Individual leukocytes were\ndrawn by vein-puncture and separated by Ficoll-paque\n(GE, Uppsala, Sweden) for genomic DNA isolation.\nSigned consent was obtained from each study subject,\napproved by the Institutional Review Board at China\nMedical University Hospital.\nGenotyping\nGenomic DNA was extracted from peripheral blood leu-\nkocytes according to standard protocol (Genomic DNA\nkit; Qiagen, Valencia, CA, USA). DNA fragments con-\ntaining target SNP sites were amplified by PCR using\nthe Taqman SNP genotyping assay system from Applied\nB i o s y s t e m s ,I n c .( C a r l s b a d ,C A ,U S A ) .T h ep r o b eI D s\nfor these SNP sites were selected from the ABI SNP\ngenotyping databank http://www.allsnps.com and listed\nin Additional file 1: Table S1. PCR amplification condi-\ntions consisted of initial denaturation at 95°C for 5 min,\nfollowed by 40 cycles of 95°C for 10 sec, and 56°C for\n10 sec. Genetic variations were detected by reading the\nfluorescence signals of PCR products. A positive fluores-\ncent signal indicates a perfect match between the probe\nand the tested DNA, thus identifying the allele type.\nStatistical analysis\nAllelic and genotypic frequency distributions for these\nSNP sites in endometriosis patients and controls were\nperformed by c\n2 analysis using SPSS software (version\n10.0, SPSS Inc. Chicago, Illinois, US). Allelic and genoty-\npic frequencies are expressed as percentages of the total\nnumber of alleles and genotypes. Odds Ratios (ORs)\nwere calculated for allelic and genotypic frequencies\nwith 95% confident interval (95% CI). Adherence to the\nHardy-Weinberg equilibrium constant was confirmed by\nc\n2 test with one degree of freedom by PLINK program\n[33].\nHaplotype association was analyzed using Bayesian\nstatistical method available in the program Phase 2.1\n[34]. Lewontin ’s coefficient D ’ and the linkage disequili-\nbrium (LD) were determined between each pairs of bial-\nlelic loci using absolute association ( r\n2) [35]. Haploview\n4.2 (Whitehead Institute for Biomedical Research, Cam-\nbridge, MA) was used to examine the structure of the\nLD block [36]. A p v a l u eo fl e s st h a n0 . 0 5w a sc o n s i d -\nered statistically significant.\nFunctional analyses and secondary structure prediction\nFunctional characterization and annotation of MUC2\nwere performed by aligning the sequence with func-\ntional motifs in PROSITE protein domain database [37].\nNetSurfP ver. 1.1 was used to predict the secondary\nstructure and surface accessibility of MUC2 [38] Relative\nChang et al . BMC Medical Genetics 2012, 13:15\nhttp://www.biomedcentral.com/1471-2350/13/15\nPage 2 of 7\n\nand absolute surface accessibility were also calculated\nfor each residue.\nResults\nMUC2 polymorphisms and endometriosis\nTo test whether SNPs in MUC2 gene play role in endo-\nmetriosis development, a total of six SNPs were selected\nfor this study, with minor allelic frequencies over 4% in\nChinese Han population based on the information in\ninternational HapMap project databank http://www.hap-\nmap.org (Additional file 1: Table S1). These SNPs and\nt h e i rL Dm a pw e r es h o w ni nF i g u r e1 A .G e n o t y p ea n d\nallele frequencies were summarized in Table 1 for both\nthe patient and the control g roups. Allele distribution\nanalyses revealed significant associations between endo-\nmetriosis and genetic variations at three of the six SNPs\n(Table 1). Endometriosis patients had significantly lower\nfrequencies of C allele at rs10794288, T allele at\nrs10902088 and G allele at rs7103978, as compared to\nthe controls ( P = 0.030, 0.013 and 0.040, respectively)\n(Table 1). Genotype analysis indicated that frequency of\nthe TT genotype at rs10902088 was significantly lower\nin patients than in controls ( P = 0.045; OR = 0.47, 95%\nCI: 0.27-0.83), while the CC genotype at rs10794288 and\nthe AG genotype at rs7103978 had protective effect\nagainst endometriosis (OR = 0.56 and 0.47, respectively;\n95% CI < 1) (Table 1). These results implied possible\nrelationship between three individual MUC2 polymorph-\nisms and endometriosis development.\nMUC2 polymorphisms and infertility\nBecause endometriosis was suggested as one source of\nfemale infertility, we asked whether genetic variations in\nMUC2 play roles in this process. The patients were sub-\ngrouped into patients with infertility or without inferti-\nlity for genotype and allele distribution analyses.\nPatients without sexual experience were excluded in this\nstudy. As shown in Table 2, the C allele at rs10794288\nand the T allele at rs10902088 were much less prevalent\nin patients with infertility ( P = 0.015 and 0.024, respec-\ntively). The TT genotype at rs10902088 were absent in\nthe infertile patient group , and genotype distribution\nwas also significantly different between the infertile and\nthe fertile patients for this SNP ( P = 0.047, data not\nshown). This finding revealed protective potential of\nthese two genetic variations in MUC2 against infertility\nin endometriosis patients.\nHaplotype analysis of MUC2 polymorphisms\nThe endometriosis-related SNPs (rs10794288,\nrs10902088 and rs7103978) found in individual tests\nwere selected for haplotype analysis of endometriosis\nand disease-related clinical symptoms. Association data\nwere enlisted in Table 3 for all the haplotypes with fre-\nquency higher than 1% presented in the case or control\ngroup. As shown in Table 3, the two most common\nhaplotypes (T-C and C-T) of rs10794288 and\nrs10902088 were significantly associated with both\nendometriosis and infertility development in the\npatients. Haplotype T-C was more common in endome-\ntriosis patients ( P = 0.012) and patients with infertility\n(P = 0.0091) (Table 3). By contrast, haplotype C-T\nmight be a protective factor against endometriosis ( P =\n0.035) and endometriosis-related infertility ( P = 0.025)\n(Table 3). Similarly, the most frequent haplotype T-C-A\nof rs10794288, rs10902088 and rs7103978 was signifi-\ncantly associated with both endometriosis ( P = 0.0063)\nand endometriosis-related infertility ( P = 0.0066) as a\nrisk factor of the disease (Table 3). In the patient group,\nL Dm a pd e m o n s t r a t e dh i g h e rl i n k a g eb e t w e e nt h e s e\nthree SNPs (Figure 1B) compared to the control group\n(Figure 1A), suggesting a genetic relationship between\nthese SNPs and endometriosis. Therefore, haplotypes of\nthese SNPs in MUC2 gene could serve as an indicator\nof susceptibility to endometriosis and endometriosis-\nrelated infertility.\nMUC2 polymorphisms and amino acid substitutions\nOne of the endometriosis-associated SNPs (rs1090\n2088) in MUC2 gene caused an amino acid substitu-\ntion (Additional file 1: Ta ble S1), and functions of\nMUC2 might be altered if such substitution changes\nsurface charge, protein stability or folding. This SNP\nlocated at amino acid Asn1149, which was predicted to\nbe within a long coil region. The relative surface acces-\nsibility of Asn1149 was estimated to be 0.707 with\nreference to a fully exposed side chain, representing a\nhighly exposed residue. Genetic variation of\nrs10902088 introduced an asparagine to lysine substi-\ntution, which was well fit in this position as a highly\nexposed residue, but the surface charge at this region\nwould be reversed. Accordingly, this substitution was\nA B\nFigure 1 Pairwise linkage disequilibrium (LD) between SNPs of\nthe MUC2 gene . LD maps were shown for controls (A) and\npatients (B). Values shown are for D ’.\nChang et al . BMC Medical Genetics 2012, 13:15\nhttp://www.biomedcentral.com/1471-2350/13/15\nPage 3 of 7\n\nmore likely to disrupt inter- or intra-molecular interac-\ntions of MUC2 rather than protein stability. On the\nother hand, rs10794288 and rs7103978 were silent\nmutations, which only influence codon usages instead\nof amino acid substitutions.\nDiscussion\nMucin proteins were known to be heavily glycosylated,\non which oligosaccharide structures turned to be\ntumor-associated antigens and are essential for antibody\nrecognition [39-41]. Our data revealed two MUC2 poly-\nmorphisms (rs10794288 and rs10902088) were asso-\nciated with endometriosis development and the related\ninfertility. Polymorphism at rs10902088 generates an\namino-acid change Asn1149Lys, while rs10794288 is a\nsilent substitution. Altho ugh Asn1149 is not a typical\nsite for N-linked glycosylation, this substitution to posi-\ntively charged residue may influence the glycosylation\nstates of several neighboring serines and Asn1154,\nwhich is within a typical N-li nked glycosylation tripep-\ntide sequon Asn-Ile-Ser [42]. Therefore, this polymorph-\nism may alter the glycosylation status of MUC2, which\nmay subsequently influence the interaction between\nMUC2 and host environments.\nTable 1 Association between SNPs in MUC2 gene and endometriosis in Taiwanese patients and controls\nSNP Genotype/allele No. (%) of patients No. (%) of controls p-valuea OR 95% CI\nrs2856111 CC 35 (18.5) 35 (18.2) 0.29 0.79 0.46-1.36\nCT 96 (50.8) 111 (57.8) 0.69 0.43-1.10\nTT 58 (30.7) 46 (24.0) 1.00\nC 166 (43.9) 181 (47.1) 0.37 0.88 0.66-1.17\nT 212 (56.1) 203 (52.9) 1.00\nrs11245936 AA 1 (0.5) 3 (1.6) 0.34 0.32 0.03-3.10\nAG 21 (11.0) 28 (14.5) 0.72 0.39-1.32\nGG 169 (88.5) 162 (83.9) 1.00\nA 23 (6.0) 34 (8.8) 0.14 0.66 0.38-1.22\nG 359 (94.0) 352 (91.2) 1.00\nrs10794288 CC 34 (17.4) 45 (23.0) 0.092 0.56 0.33-0.96\nCT 87 (44.6) 96 (49.0) 0.67 0.43-1.06\nTT 74 (37.9) 55 (28.0) 1.00\nC 155 (39.7) 186 (47.4) 0.030* 0.73 0.55-0.97\nT 235 (60.3) 206 (52.6) 1.00\nrs10902088 TT 27 (14.0) 43 (22.3) 0.045* 0.47 0.27-0.83\nCT 93 (48.2) 95 (49.2) 0.74 0.47-1.16\nCC 73 (37.8) 55 (28.5) 1.00\nT 147 (38.1) 181 (47.4) 0.013* 0.70 0.52-0.93\nC 239 (61.9) 205 (52.6) 1.00\nrs7103978 GG 2 (1.0) 1 (0.5) 0.053 1.84 0.16-21.58\nAG 19 (9.8) 37 (18.9) 0.47 0.26-0.85\nAA 172 (89.1) 158 (80.6) 1.00\nG 23 (6.0) 39 (9.9) 0.040* 0.57 0.34-0.98\nA 363 (94.0) 353 (90.1) 1.00\nrs11245954 GG 0 (0.0) 0 (0.0) NA NA NA\nAG 21 (10.8) 26 (13.5) 0.78 0.42-1.43\nAA 173 (89.2) 166 (86.5) 1.00\nG 21 (5.4) 26 (6.8) 0.43 0.79 0.44-1.43\nA 367 (94.6) 358 (93.2) 1.00\n*Indicates statistical significance\naP-values were calculated using c2 test without corrections for multiple test\nTable 2 Association between allele distributions of SNPs\nin MUC2 and endometriosis-related infertility\nSNP Infertile\nMAF\nNon-Infertile\nMAF\nP-valuea OR 95% CI\nrs2856111 48.1 41.3 0.36 1.32 0.73-2.38\nrs11245936 3.8 5.4 0.64 0.70 0.16-3.16\nrs10794288 24.1 41.7 0.015* 0.44 0.23-0.87\nrs10902088 26.0 43.1 0.024* 0.46 0.24-0.91\nrs7103978 5.8 5.8 0.99 0.99 0.28-3.54\nrs11245954 3.8 4.7 0.79 0.82 0.18-3.72\n*Indicates statistical significance\nMAF minor allele frequency\naP-values were calculated using c2 test\nChang et al . BMC Medical Genetics 2012, 13:15\nhttp://www.biomedcentral.com/1471-2350/13/15\nPage 4 of 7\n\nEndometriosis development is associated with altered\ninflammatory and immune responses, while clinical fea-\nture of endometriosis also mimics malignant reproduc-\ntive disease, such as progressive invasion to adherent\npelvic organ and recurrence abilities. Mucins are\nsecreted by epithelium cells of reproductive tissues, gen-\nerating the mucus of cervix and endometrium, which\nplays an important role in reproductive physiology.\nImpaired mucin secretion could impede spermatozoa\nmigration, which may contribute to female infertility.\nUnlike the less consistent expression patterns of MUC1,\nMUC6 and MUC5AC in normal and cancer tissues,\nMUC2 levels were always measured low in normal\nendometrial and cervical tissue, and elevated MUC2\nexpressions were specifically found in various neoplastic\nlesions [28,29,43-45]. However, expression patterns of\nMUC2 in ovarian tumor were heterogenic [18]. Boman\net al. reported that MUC2 were mainly present in\nbenign and borderline ovarian tumor [46], while Dong\net al. showed that breast cancer patients with presence\nof MUC2 expression had short er disease-free survival\n[47]. We found that the minor allele of rs7103978\ndecreases the cognate co don frequency from 15.8 ‰ to\n7.8‰ (Kazusa DNA Res. Inst. http://www.kazusa.or.jp/\ncodon/), which may increase the odds of premature\ntranslation termination and thus reduce MUC2 level.\nTherefore, our result suggested that expression of\nMUC2 may facilitate cell invasion or proliferation abil-\nities. The observed association of MUC2 polymorphisms\nand endometriosis may help us further elucidate the\nlink between endometriosis and certain subtypes of\novarian cancer, if such genetic alterations were also pre-\nsent in the ovarian cancer patients.\nAlthough endometriosis could cause pelvic adhesion\nand tubal occlusion which lead to infertility, some\npatients without anatomic disruption still had the pro-\nblem of impaired fertilizati on. Possible mechanisms of\nendometriosis-related infertility include impaired follicu-\nlogenesis induced by abnormal immunological, chemical\nfactors or toxins, poor oocyte quality, inhibited binding\nof spermatozoa to the zona-pellucida and impaired\nimplantation of embryo. This phenomenon was corre-\nlated to changes of cytokines and growth factors in\nendometrium, follicular fluid and peritoneal fluid [8].\nPrevious studies have alread y showed the positive asso-\nciation of endometriosis and polymorphism of cytokine\ngenes [7,48]. Li et al. showed that macrophage induced\nIL-6 up-regulated the MUC1 but down-regulated MUC2\nexpression [9]. Up-regulation of MUC1 was associated\nwith implantation failure [22]. IL-1 was also found to\nup-regulate MUC2 expression, and IL-1 was thought to\nregulate immune and inflammation response in endo-\nmetrium and modulate extracellular matrix modeling of\nendometrium during menstruation and implantation\n[49]. Moreover, previous studies demonstrated that IL-8,\nTNF-a and NF- /C20B tend to increase in the peritoneal\nfluid according to the severity of dysmenorrhea, extent\npelvic adhesion and proliferation of endometrial stroma\ncells, and MUC2 expression could increase accordingly\nvia activation of NF- /C20B pathway through these cytokines\n[50-52]. Therefore, it is plausible that altered level of\nMUC2 could affect fertilit y as a downstream effecter\nthat can further influence the secretion of mucus, sperm\nmotility, oocyte quality and receptivity of endometrium.\nConclusions\nIn this study, our data revealed a significant association\nbetween MUC2 polymorphisms and endometriosis in a\nTaiwanese population. Th er e s u l t si m p l yt h a tM U C 2\nmay play a role in the pathogenesis of endometriosis\nand endometriosis-related infertility, while the mechan-\nisms underlying this phenomenon remain to be eluci-\ndated. As a major secreted form of mucins, MUC2 may\nhave the ability to affect more surrounding tissues than\nthe membrane-bound form of mucins. Since MUC2 is\nnot as well investigated as some other mucins in repro-\nductive organs, its molecular function in endometriosis\nand infertility is worth future study.\nTable 3 Association between MUC2 haplotypes and endometriosis or endometriosis-related infertility\nSNP marker Haplotype Endometriosis Endometriosis-related infertility\nCase (%) Control (%) P-valuea Infertility (%) Non-infertility (%) P-valuea\nrs10794288, rs10902088 T-C 58.6 49.6 0.012* 74.9 57.2 0.0091*\nC-T 35.8 43.2 0.035* 23.4 38.3 0.025*\nC-C 3.4 3.7 0.83 0.1 2.6 0.20\nT-T 2.1 3.5 0.27 1.6 1.9 0.89\nrs10794288, rs10902088, rs7103978 T-C-A 57.8 48.1 0.0063* 74.8 56.3 0.0066*\nC-T-A 32.0 35.9 0.25 22.0 34.1 0.06\nC-T-G 3.8 7.2 0.036* 1.4 4.2 0.29\nC-C-A 3.4 3.7 0.81 0 2.6 0.20\nT-T-G 1.5 2.0 0.61 1.6 1.1 0.76\n*Indicates statistical significance. aP-values were calculated using c2 test\nChang et al . BMC Medical Genetics 2012, 13:15\nhttp://www.biomedcentral.com/1471-2350/13/15\nPage 5 of 7\n\nAdditional material\nAdditional file 1: Table S1 . Probes been used for SNPs in MUC2 gene.\nAcknowledgements\nWe appreciate the kind assistance from Ms Carmen Chan at China Medical\nUniversity Hospital. This work was supported by the grant from China\nMedical University Hospital (DMR-99-091) and the China Medical University-\nAsia University Research Collaboration Fund (CMU98-asia-02), Taichung,\nTaiwan.\nAuthor details\n1Department of Obstetrics and Gynecology, China Medical University\nHospital, 2 Yude Road, 40402 Taichung, Taiwan. 2Institute of Public Health,\nChina Medical University, 91 Hsueh-Shih Road, 40447 Taichung, Taiwan.\n3Human Genetics Center, China Medical University Hospital, 2 Yude Road,\n40447 Taichung, Taiwan. 4Department of Obstetrics and Gynecology, Mackay\nMemorial Hospital, 92 Sec. 2 Zhongshan Road, 10449 Taipei, Taiwan. 5School\nof Medical Imaging and Radiological Sciences, Chung Shan Medical\nUniversity, 110 Sec.1 Jianguo N. Rd, 40201 Taichung, Taiwan. 6School of\nChinese Medicine, China Medical University, 91 Hsueh-Shih Road, 40447\nTaichung, Taiwan. 7Department of Health and Nutrition Biotechnology, Asia\nUniversity, 500 Lioufeng Road, 41354 Taichung, Taiwan. 8School of Post-\nBaccalaureate Chinese Medicine, China Medical University, 91 Hsueh-Shih\nRoad, 40447 Taichung, Taiwan.\nAuthors’ contributions\nCY-YC and YC: study design, execution and manuscript drafting; YC and C-\nMC: statistical analysis; CY-YC, W-CL and F-JT: patient collection; C-PC, S-CL\nand JJ-CS: critical discussion and manuscript editing. All authors read and\napproved the final manuscript.\nCompeting interests\nThe authors declare that they have no competing interests.\nReceived: 17 October 2011 Accepted: 15 March 2012\nPublished: 15 March 2012\nReferences\n1. Ballard K, Lowton K, Wright J: What’s the delay? A qualitative study of\nwomen’s experiences of reaching a diagnosis of endometriosis. Fertil\nSteril 2006, 86(5):1296-1301.\n2. Bhattacharya S, Porter M, Amalraj E, Templeton A, Hamilton M, Lee AJ,\nKurinczuk JJ: The epidemiology of infertility in the North East of\nScotland. Hum Reprod 2009, 24(12):3096-3107.\n3. Ozkan S, Murk W, Arici A: Endometriosis and infertility: epidemiology and\nevidence-based treatments. Ann N Y Acad Sci 2008, 1127:92-100.\n4. Vercellini P, Somigliana E, Vigano P, Abbiati A, Barbara G, Fedele L: ’Blood\nOn The Tracks ’ from corpora lutea to endometriomas. BJOG 2009,\n116(3):366-371.\n5. Stefansson H, Geirsson RT, Steinthorsdottir V, Jonsson H, Manolescu A,\nKong A, Ingadottir G, Gulcher J, Stefansson K: Genetic factors contribute to\nthe risk of developing endometriosis. Hum Reprod 2002, 17(3):555-559.\n6. Lebovic DI, Mueller MD, Taylor RN: Immunobiology of endometriosis. Fertil\nSteril 2001, 75(1):1-10.\n7. Falconer H, D ’Hooghe T, Fried G: Endometriosis and genetic\npolymorphisms. Obstet Gynecol Surv 2007, 62(9):616-628.\n8. Gupta S, Goldberg JM, Aziz N, Goldberg E, Krajcir N, Agarwal A: Pathogenic\nmechanisms in endometriosis-associated infertility. Fertil Steril 2008,\n90(2):247-257.\n9. Li YY, Hsieh LL, Tang RP, Liao SK, Yeh KY: Macrophage-derived interleukin-\n6 up-regulates MUC1, but down-regulates MUC2 expression in the\nhuman colon cancer HT-29 cell line. Cell Immunol 2009, 256(1-2):19-26.\n10. Christodoulakos G, Augoulea A, Lambrinoudaki I, Sioulas V, Creatsas G:\nPathogenesis of endometriosis: the role of defective\n‘immunosurveillance’. Eur J Contracept Reprod Health Care 2007,\n12(3):194-202.\n11. Gonzalez-Ramos R, Van Langendonckt A, Defrere S, Lousse JC, Colette S,\nDevoto L, Donnez J: Involvement of the nuclear factor-kappaB pathway\nin the pathogenesis of endometriosis. Fertil Steril 2010, 94(6):1985-1994.\n12. Kyama CM, Overbergh L, Debrock S, Valckx D, Vander Perre S, Meuleman C,\nMihalyi A, Mwenda JM, Mathieu C, D ’Hooghe TM: Increased peritoneal and\nendometrial gene expression of biologically relevant cytokines and\ngrowth factors during the menstrual phase in women with\nendometriosis. Fertil Steril 2006, 85(6):1667-1675.\n13.\nPellicer A, Albert C, Mercader A, Bonilla-Musoles F, Remohi J, Simon C: The\nfollicular and endocrine environment in women with endometriosis:\nlocal and systemic cytokine production. Fertil Steril 1998, 70(3):425-431.\n14. Carlberg M, Nejaty J, Froysa B, Guan Y, Soder O, Bergqvist A: Elevated\nexpression of tumour necrosis factor alpha in cultured granulosa cells\nfrom women with endometriosis. Hum Reprod 2000, 15(6):1250-1255.\n15. Yonezawa S, Goto M, Yamada N, Higashi M, Nomoto M: Expression profiles\nof MUC1, MUC2, and MUC4 mucins in human neoplasms and their\nrelationship with biological behavior. Proteomics 2008, 8(16):3329-3341.\n16. Agrawal B, Krantz MJ, Parker J, Longenecker BM: Expression of MUC1\nmucin on activated human T cells: implications for a role of MUC1 in\nnormal immune regulation. Cancer Res 1998, 58(18):4079-4081.\n17. Correa I, Plunkett T, Vlad A, Mungul A, Candelora-Kettel J, Burchell JM,\nTaylor-Papadimitriou J, Finn OJ: Form and pattern of MUC1 expression on\nT cells activated in vivo or in vitro suggests a function in T-cell\nmigration. Immunology 2003, 108(1):32-41.\n18. Tornos C, Soslow R, Chen S, Akram M, Hummer AJ, Abu-Rustum N,\nNorton L, Tan LK: Expression of WT1, CA 125, and GCDFP-15 as useful\nmarkers in the differential diagnosis of primary ovarian carcinomas\nversus metastatic breast cancer to the ovary. Am J Surg Pathol 2005,\n29(11):1482-1489.\n19. Gendler SJ, Lancaster CA, Taylor-Papadimitriou J, Duhig T, Peat N, Burchell J,\nPemberton L, Lalani EN, Wilson D: Molecular cloning and expression of\nhuman tumor-associated polymorphic epithelial mucin. J Biol Chem 1990,\n265(25):15286-15293.\n20. Williams SJ, McGuckin MA, Gotley DC, Eyre HJ, Sutherland GR, Antalis TM:\nTwo novel mucin genes down-regulated in colorectal cancer identified\nby differential display. Cancer Res 1999, 59(16):4083-4089.\n21. Vlad AM, Diaconu I, Gantt KR: MUC1 in endometriosis and ovarian cancer.\nImmunol Res 2006, 36(1-3):229-236.\n22. Horne AW, Lalani EN, Margara RA, Ryder TA, Mobberley MA, White JO: The\nexpression pattern of MUC1 glycoforms and other biomarkers of\nendometrial receptivity in fertile and infertile women. Mol Reprod Dev\n2005, 72(2):216-229.\n23. Chang CY, Chang HW, Chen CM, Lin CY, Chen CP, Lai CH, Lin WY, Liu HP,\nSheu JJ, Tsai FJ: MUC4 gene polymorphisms associate with\nendometriosis development and endometriosis-related infertility. BMC\nMed 2011, 9:19.\n24. Gum JR Jr, Hicks JW, Toribara NW, Siddiki B, Kim YS: Molecular cloning of\nhuman intestinal mucin (MUC2) cDNA. Identification of the amino\nterminus and overall sequence similarity to prepro-von Willebrand\nfactor. J Biol Chem 1994, 269(4):2440-2446.\n25. Ahn DH, Crawley SC, Hokari R, Kato S, Yang SC, Li JD, Kim YS: TNF-alpha\nactivates MUC2 transcription via NF-kappaB but inhibits via JNK\nactivation. Cell Physiol Biochem 2005, 15(1-4):29-40.\n26. Kim YD, Jeon JY, Woo HJ, Lee JC, Chung JH, Song SY, Yoon SK, Baek SH:\nInterleukin-1beta induces MUC2 gene expression and mucin secretion\nvia activation of PKC-MEK/ERK, and PI3K in human airway epithelial\ncells. J Korean Med Sci 2002, 17(6):765-771.\n27.\nIwashita J, Sato Y, Sugaya H, Takahashi N, Sasaki H, Abe T: mRNA of MUC2\nis stimulated by IL-4, IL-13 or TNF-alpha through a mitogen-activated\nprotein kinase pathway in human colon cancer cells. Immunol Cell Biol\n2003, 81(4):275-282.\n28. Babu SD, Jayanthi V, Devaraj N, Reis CA, Devaraj H: Expression profile of\nmucins (MUC2, MUC5AC and MUC6) in Helicobacter pylori infected pre-\nneoplastic and neoplastic human gastric epithelium. Mol Cancer 2006,\n5:10.\n29. Riethdorf L, O ’Connell JT, Riethdorf S, Cviko A, Crum CP: Differential\nexpression of MUC2 and MUC5AC in benign and malignant glandular\nlesions of the cervix uteri. Virchows Arch 2000, 437(4):365-371.\n30. Kim YS, Ho SB: Intestinal goblet cells and mucins in health and disease:\nrecent insights and progress. Curr Gastroenterol Rep 2010, 12(5):319-330.\nChang et al . BMC Medical Genetics 2012, 13:15\nhttp://www.biomedcentral.com/1471-2350/13/15\nPage 6 of 7\n\n31. Voynow JA, Gendler SJ, Rose MC: Regulation of mucin genes in chronic\ninflammatory airway diseases. Am J Respir Cell Mol Biol 2006,\n34(6):661-665.\n32. Revised American Society for Reproductive Medicine classification of\nendometriosis: 1996. Fertil Steril 1997, 67(5):817-821.\n33. Purcell S, Neale B, Todd-Brown K, Thomas L, Ferreira MA, Bender D, Maller J,\nSklar P, de Bakker PI, Daly MJ, et al : PLINK: a tool set for whole-genome\nassociation and population-based linkage analyses. Am J Hum Genet\n2007, 81(3):559-575.\n34. Stephens M, Donnelly P: A comparison of bayesian methods for\nhaplotype reconstruction from population genotype data. Am J Hum\nGenet 2003, 73(5):1162-1169.\n35. Hedrick PW: Gametic disequilibrium measures: proceed with caution.\nGenetics 1987, 117(2):331-341.\n36. Barrett JC, Fry B, Maller J, Daly MJ: Haploview: analysis and visualization of\nLD and haplotype maps. Bioinformatics 2005, 21(2):263-265.\n37. Sigrist CJ, Cerutti L, Hulo N, Gattiker A, Falquet L, Pagni M, Bairoch A,\nBucher P: PROSITE: a documented database using patterns and profiles\nas motif descriptors. Brief Bioinform 2002, 3(3):265-274.\n38. Petersen B, Petersen TN, Andersen P, Nielsen M, Lundegaard C: A generic\nmethod for assignment of reliability scores applied to solvent\naccessibility predictions. BMC Struct Biol 2009, 9:51.\n39. Magnani JL, Steplewski Z, Koprowski H, Ginsburg V: Identification of the\ngastrointestinal and pancreatic cancer-associated antigen detected by\nmonoclonal antibody 19-9 in the sera of patients as a mucin. Cancer Res\n1983, 43(11):5489-5492.\n40. Goldenberg DM, Pegram CA, Vazquez JJ: Identification of a colon-specific\nantigen (CSA) in normal and neoplastic tissues. J Immunol 1975,\n114(3):1008-1013.\n41. Gendler SJ, Burchell JM, Duhig T, Lamport D, White R, Parker M, Taylor-\nPapadimitriou J: Cloning of partial cDNA encoding differentiation and\ntumor-associated mucin glycoproteins expressed by human mammary\nepithelium. Proc Natl Acad Sci USA 1987, 84(17):6060-6064.\n42. Jones J, Krag SS, Betenbaugh MJ: Controlling N-linked glycan site\noccupancy. Biochim Biophys Acta 2005, 1726(2):121-137.\n43. Levi E, Klimstra DS, Andea A, Basturk O, Adsay NV: MUC1 and MUC2 in\npancreatic neoplasia. J Clin Pathol 2004, 57(5):456-462.\n44. Jankovic Velickovic L, Katic V, Hattori T, Kushima R, Marjanovic G,\nStefanovic V: Differences in the expression of mucins in various forms of\ncystitis glandularis. Pathol Res Pract 2007, 203(9):653-658.\n45. Ho SB, Niehans GA, Lyftogt C, Yan PS, Cherwitz DL, Gum ET, Dahiya R,\nKim YS: Heterogeneity of mucin gene expression in normal and\nneoplastic tissues. Cancer Res 1993, 53(3):641-651.\n46. Boman F, Buisine MP, Wacrenier A, Querleu D, Aubert JP, Porchet N: Mucin\ngene transcripts in benign and borderline mucinous tumours of the\novary: an in situ hybridization study. J Pathol 2001, 193(3):339-344.\n47. Dong Y, Walsh MD, Cummings MC, Wright RG, Khoo SK, Parsons PG,\nMcGuckin MA: Expression of MUC1 and MUC2 mucins in epithelial\novarian tumours. J Pathol 1997, 183(3):311-317.\n48. Poliness AE, Healey MG, Brennecke SP, Moses EK: Proteomic approaches in\nendometriosis research. Proteomics 2004, 4(7):1897-1902.\n49. Kim YD, Kwon EJ, Park DW, Song SY, Yoon SK, Baek SH: Interleukin-1beta\ninduces MUC2 and MUC5AC synthesis through cyclooxygenase-2 in NCI-\nH292 cells. Mol Pharmacol 2002, 62(5):1112-1118.\n50. Sakamoto Y, Harada T, Horie S, Iba Y, Taniguchi F, Yoshida S, Iwabe T,\nTerakawa N: Tumor necrosis factor-alpha-induced interleukin-8 (IL-8)\nexpression in endometriotic stromal cells, probably through nuclear\nfactor-kappa B activation: gonadotropin-releasing hormone agonist\ntreatment reduced IL-8 expression. J Clin Endocrinol Metab 2003,\n88(2):730-735.\n51. Grund EM, Kagan D, Tran CA, Zeitvogel A, Starzinski-Powitz A, Nataraja S,\nPalmer SS: Tumor necrosis factor-alpha regulates inflammatory and\nmesenchymal responses via mitogen-activated protein kinase kinase,\np38, and nuclear factor kappaB in human endometriotic epithelial cells.\nMol Pharmacol 2008, 73(5):1394-1404.\n52. Wu J, Gong J, Geng J, Song Y: Deoxycholic acid induces the\noverexpression of intestinal mucin, MUC2, via NF-kB signaling pathway\nin human esophageal adenocarcinoma cells. BMC Cancer 2008, 8:333.\nPre-publication history\nThe pre-publication history for this paper can be accessed here:\nhttp://www.biomedcentral.com/1471-2350/13/15/prepub\ndoi:10.1186/1471-2350-13-15\nCite this article as: Chang et al .: MUC2 polymorphisms are associated\nwith endometriosis development and infertility: a case-control study.\nBMC Medical Genetics 2012 13:15.\nSubmit your next manuscript to BioMed Central\nand take full advantage of: \n• Convenient online submission\n• Thorough peer review\n• No space constraints or color figure charges\n• Immediate publication on acceptance\n• Inclusion in PubMed, CAS, Scopus and Google Scholar\n• Research which is freely available for redistribution\nSubmit your manuscript at \nwww.biomedcentral.com/submit\nChang et al . BMC Medical Genetics 2012, 13:15\nhttp://www.biomedcentral.com/1471-2350/13/15\nPage 7 of 7","source_license":"CC0","license_restricted":false}