Gene Summary

Gene:MUC17; mucin 17, cell surface associated
Aliases: MUC3, MUC-3, MUC-17
Summary:The protein encoded by this gene is a membrane-bound mucin that provides protection to gut epithelial cells. The encoded protein contains about 60 tandem repeats, with each repeat being around 60 aa. N-glycosylation enables the encoded protein to localize on the cell surface, while the C-terminus interacts with the scaffold protein PDZ domain containing 1 (PDZK1). Two transcript variants, one protein-coding and the other non-protein coding, have been found for this gene. [provided by RefSeq, Nov 2015]
Databases:VEGA, OMIM, HGNC, Ensembl, GeneCard, Gene
Source:NCBIAccessed: 15 March, 2017


What does this gene/protein do?
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Cancer Overview

Research Indicators

Publications Per Year (1992-2017)
Graph generated 15 March 2017 using data from PubMed using criteria.

Literature Analysis

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Tag cloud generated 15 March, 2017 using data from PubMed, MeSH and CancerIndex

Specific Cancers (2)

Data table showing topics related to specific cancers and associated disorders. Scope includes mutations and abnormal protein expression.

Note: list is not exhaustive. Number of papers are based on searches of PubMed (click on topic title for arbitrary criteria used).

Latest Publications: MUC17 (cancer-related)

Zhang J, Huang JY, Chen YN, et al.
Whole genome and transcriptome sequencing of matched primary and peritoneal metastatic gastric carcinoma.
Sci Rep. 2015; 5:13750 [PubMed] Free Access to Full Article Related Publications
Gastric cancer is one of the most aggressive cancers and is the second leading cause of cancer death worldwide. Approximately 40% of global gastric cancer cases occur in China, with peritoneal metastasis being the prevalent form of recurrence and metastasis in advanced disease. Currently, there are limited clinical approaches for predicting and treatment of peritoneal metastasis, resulting in a 6-month average survival time. By comprehensive genome analysis will uncover the pathogenesis of peritoneal metastasis. Here we describe a comprehensive whole-genome and transcriptome sequencing analysis of one advanced gastric cancer case, including non-cancerous mucosa, primary cancer and matched peritoneal metastatic cancer. The peripheral blood is used as normal control. We identified 27 mutated genes, of which 19 genes are reported in COSMIC database (ZNF208, CRNN, ATXN3, DCTN1, RP1L1, PRB4, PRB1, MUC4, HS6ST3, MUC17, JAM2, ITGAD, IREB2, IQUB, CORO1B, CCDC121, AKAP2, ACAN and ACADL), and eight genes have not previously been described in gastric cancer (CCDC178, ARMC4, TUBB6, PLIN4, PKLR, PDZD2, DMBT1and DAB1).Additionally,GPX4 and MPND in 19q13.3-13.4 region, is characterized as a novel fusion-gene. This study disclosed novel biological markers and tumorigenic pathways that would predict gastric cancer occurring peritoneal metastasis.

Shibahara H, Higashi M, Yokoyama S, et al.
A comprehensive expression analysis of mucins in appendiceal carcinoma in a multicenter study: MUC3 is a novel prognostic factor.
PLoS One. 2014; 9(12):e115613 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: Mucins are implicated in survival in various cancers, but there have been no report addressed on survival in appendiceal carcinoma, an uncommon disease with different clinical and pathological features from those of other colon cancers. We aimed to investigate the clinical implications of expression of mucins in appendiceal carcinoma.
METHODS: Expression profiles of MUC1, MUC2, MUC3, MUC4, MUC5AC, MUC6, MUC16 and MUC17 in cancer tissue were examined by immunohistochemistry in 108 cases of surgically resected appendiceal carcinoma.
RESULTS: The following relationships of mucins with clinicopathologic factors were identified: MUC1 with positive lymphatic invasion (p = 0.036); MUC2 with histological type (mucinous carcinoma, p<0.001), superficial invasion depth (p = 0.007), negative venous invasion (p = 0.003), and curative resection (p = 0.019); MUC3 with non-curative resection (p = 0.017); MUC5AC with histological type (mucinous carcinoma, p = 0.002), negative lymphatic invasion (p = 0.021), and negative venous invasion (p = 0.022); and MUC16 with positive lymph node metastasis (p = 0.035), positive venous invasion (p<0.05), and non-curative resection (p = 0.035). A poor prognosis was related to positive lymph node metastasis (p = 0.04), positive lymphatic invasion (p = 0.02), positive venous invasion (p<0.001), non-curative resection (p<0.001), and positive expression of MUC3 (p = 0.004). In multivariate analysis, positive venous invasion (HR: 6.93, 95% CI: 1.93-24.96, p = 0.003), non-curative resection (HR: 10.19, 95% CI: 3.05-34.07, p<0.001) and positive MUC3 expression (HR: 3.37, 95% CI: 1.13-10.03, p = 0.03) were identified as significant independent prognostic factors in patients with appendiceal carcinoma.
CONCLUSIONS: Expression of MUC3 in appendiceal carcinoma is an independent factor for poor prognosis and a useful predictor of outcome in patients with appendiceal carcinoma after surgery.

Shibahara H, Higashi M, Koriyama C, et al.
Pathobiological implications of mucin (MUC) expression in the outcome of small bowel cancer.
PLoS One. 2014; 9(4):e86111 [PubMed] Free Access to Full Article Related Publications
Mucins have been associated with survival in various cancer patients, but there have been no studies of mucins in small bowel carcinoma (SBC). In this study, we investigated the relationships between mucin expression and clinicopathologic factors in 60 SBC cases, in which expression profiles of MUC1, MUC2, MUC3, MUC4, MUC5AC, MUC6 and MUC16 in cancer and normal tissues were examined by immunohistochemistry. MUC1, MUC5AC and MUC16 expression was increased in SBC lesions compared to the normal epithelium, and expression of these mucins was related to clinicopathologic factors, as follows: MUC1 [tumor location (p = 0.019), depth (p = 0.017) and curability (p = 0.007)], MUC5AC [tumor location (p = 0.063) and lymph node metastasis (p = 0.059)], and MUC16 [venous invasion (p = 0.016) and curability (p = 0.016)]. Analysis of 58 cases with survival data revealed five factors associated with a poor prognosis: poorly-differentiated or neuroendocrine histological type (p<0.001), lymph node metastasis (p<0.001), lymphatic invasion (p = 0.026), venous invasion (p<0.001) and curative resection (p<0.001), in addition to expression of MUC1 (p = 0.042), MUC5AC (p = 0.007) and MUC16 (p<0.001). In subsequent multivariate analysis with curability as the covariate, lymph node metastasis, venous invasion, and MUC5AC and/or MUC16 expression were significantly related to the prognosis. Multivariate analysis in curative cases (n = 45) showed that SBC with MUC5AC and/or MUC16 expression had a significantly independent high hazard risk after adjusting for the effects of venous invasion (hazard ratio: 5.6, 95% confidence interval: 1.8-17). In conclusion, the study shows that a MUC5AC-positive and/or MUC16-positive status is useful as a predictor of a poor outcome in patients with SBC.

Delker DA, McGettigan BM, Kanth P, et al.
RNA sequencing of sessile serrated colon polyps identifies differentially expressed genes and immunohistochemical markers.
PLoS One. 2014; 9(2):e88367 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: Sessile serrated adenomas/polyps (SSA/Ps) may account for 20-30% of colon cancers. Although large SSA/Ps are generally recognized phenotypically, small (<1 cm) or dysplastic SSA/Ps are difficult to differentiate from hyperplastic or small adenomatous polyps by endoscopy and histopathology. Our aim was to define the comprehensive gene expression phenotype of SSA/Ps to better define this cancer precursor.
RESULTS: RNA sequencing was performed on 5' capped RNA from seven SSA/Ps collected from patients with the serrated polyposis syndrome (SPS) versus eight controls. Highly expressed genes were analyzed by qPCR in additional SSA/Ps, adenomas and controls. The cellular localization and level of gene products were examined by immunohistochemistry in syndromic and sporadic SSA/Ps, adenomatous and hyperplastic polyps and controls. We identified 1,294 differentially expressed annotated genes, with 106 increased ≥10-fold, in SSA/Ps compared to controls. Comparing these genes with an array dataset for adenomatous polyps identified 30 protein coding genes uniquely expressed ≥10-fold in SSA/Ps. Biological pathways altered in SSA/Ps included mucosal integrity, cell adhesion, and cell development. Marked increased expression of MUC17, the cell junction protein genes VSIG1 and GJB5, and the antiapoptotic gene REG4 were found in SSA/Ps, relative to controls and adenomas, were verified by qPCR analysis of additional SSA/Ps (n = 21) and adenomas (n = 10). Immunohistochemical staining of syndromic (n≥11) and sporadic SSA/Ps (n≥17), adenomatous (n≥13) and hyperplastic (n≥10) polyps plus controls (n≥16) identified unique expression patterns for VSIG1 and MUC17 in SSA/Ps.
CONCLUSION: A subset of genes and pathways are uniquely increased in SSA/Ps, compared to adenomatous polyps, thus supporting the concept that cancer develops by different pathways in these phenotypically distinct polyps with markedly different gene expression profiles. Immunostaining for a subset of these genes differentiates both syndromic and sporadic SSA/Ps from adenomatous and hyperplastic polyps.

Lin ZF, Shen XY, Lu FZ, et al.
Reveals new lung adenocarcinoma cancer genes based on gene expression.
Eur Rev Med Pharmacol Sci. 2012; 16(9):1249-56 [PubMed] Related Publications
BACKGROUND: Lung adenocarcinoma (LAC) is the most common type of lung cancer, accounting for 30-35% of all cases.
AIM: In this study we aim to predict potential genes and confirm pathways which are associated with LAC.
MATERIALS AND METHODS: By using the meta-analysis method, GSE10072 and GSE 2514 datasets were merged to find potential genes and pathways which are associated with LAC.
RESULTS: Our analysis indicated identified differentially expressed genes enriched in multicellular organismal metabolic process, gland development, and urogenital system development. Further, we predicted genes including EGF-like domain might be the potential target genes for further study, such as NGX6, MUC17, and Nel. In addition, a number of genes that associated with axon guidance, focal adhesion, and complement and coagulation cascades pathway might be also involved in LAC in a direct or indirectly manner.
CONCLUSIONS: Our analysis indicated identified differentially expressed genes enriched in multicellular organismal metabolic process, gland development, and urogenital system development We anticipate numerous advances in LAC research in the coming years based on our meta-analysis.

Kitamoto S, Yokoyama S, Higashi M, et al.
Expression of MUC17 is regulated by HIF1α-mediated hypoxic responses and requires a methylation-free hypoxia responsible element in pancreatic cancer.
PLoS One. 2012; 7(9):e44108 [PubMed] Free Access to Full Article Related Publications
MUC17 is a type 1 membrane-bound glycoprotein that is mainly expressed in the digestive tract. Recent studies have demonstrated that the aberrant overexpression of MUC17 is correlated with the malignant potential of pancreatic ductal adenocarcinomas (PDACs); however, the exact regulatory mechanism of MUC17 expression has yet to be identified. Here, we provide the first report of the MUC17 regulatory mechanism under hypoxia, an essential feature of the tumor microenvironment and a driving force of cancer progression. Our data revealed that MUC17 was significantly induced by hypoxic stimulation through a hypoxia-inducible factor 1α (HIF1α)-dependent pathway in some pancreatic cancer cells (e.g., AsPC1), whereas other pancreatic cancer cells (e.g., BxPC3) exhibited little response to hypoxia. Interestingly, these low-responsive cells have highly methylated CpG motifs within the hypoxia responsive element (HRE, 5'-RCGTG-3'), a binding site for HIF1α. Thus, we investigated the demethylation effects of CpG at HRE on the hypoxic induction of MUC17. Treatment of low-responsive cells with 5-aza-2'-deoxycytidine followed by additional hypoxic incubation resulted in the restoration of hypoxic MUC17 induction. Furthermore, DNA methylation of HRE in pancreatic tissues from patients with PDACs showed higher hypomethylation status as compared to those from non-cancerous tissues, and hypomethylation was also correlated with MUC17 mRNA expression. Taken together, these findings suggested that the HIF1α-mediated hypoxic signal pathway contributes to MUC17 expression, and DNA methylation of HRE could be a determinant of the hypoxic inducibility of MUC17 in pancreatic cancer cells.

Rossi G, Gasser B, Sartori G, et al.
MUC5AC, cytokeratin 20 and HER2 expression and K-RAS mutations within mucinogenic growth in congenital pulmonary airway malformations.
Histopathology. 2012; 60(7):1133-43 [PubMed] Related Publications
AIMS:   To analyse the expression of several mucins (MUC1, MUC2, MUC3, MUC5AC and MUC6), epidermal growth factor receptor (EGFR), v-erb-b2 erythroblastic leukaemia viral oncogene homologue 2 (HER2), thyroid transcription factor-1 (TTF-1), caudal type homeobox 2 (CDX2) and cytokeratin 20 (CK20), and the presence of mutations of EGFR, KRAS and HER2 in congenital pulmonary airway malformations (CPAM).
METHODS AND RESULTS:   Forty-one cases of CPAM and six pulmonary sequestrations were included. TTF-1 expression was observed in all cases but was not seen in mucinogenic growths in CPAM. CDX2 expression was completely negative. MUC1 expression was noted in 12 (29%) CPAM and in 33% sequestrations. MUC5AC was noted in only five cases (26%) by immunohistochemistry and was found in the mucinogenic proliferations of type 1 CPAM. No immunolabelling was noted for the other mucins. EGFR was expressed variably in almost all cases, while HER2 and CK20 was seen exclusively in the mucinogenic proliferations. All mucinous growths were characterized by KRAS mutations. No EGFR and HER2 gene alterations were identified.
CONCLUSIONS:   KRAS mutations and MUC5AC, CK20 and HER2 expression was seen in all mucinogenic proliferations, supporting the neoplastic nature of these cytologically bland growths. These findings emphasize the importance of complete surgical resection of such lesions.

Mahomed F
Recent advances in mucin immunohistochemistry in salivary gland tumors and head and neck squamous cell carcinoma.
Oral Oncol. 2011; 47(9):797-803 [PubMed] Related Publications
This review focuses on the immunohistochemical expression of members of the MUC-type mucin family in salivary gland tumors and head and neck squamous cell carcinomas (HNSCC). Information is available on changes in the expression levels and distribution profiles of MUC1, MUC2, MUC3, MUC4, MUC5AC, MUC5B, MUC6 and MUC7 in tumors of the salivary glands; and of MUC1, MUC2 and MUC4 in HNSCC. In salivary gland tumors the expression patterns of MUC2, MUC3, MUC5AC and MUC6 appear to be very closely correlated with the histopathological tumor type indicating their potential use to improve diagnostic accuracy in salivary gland neoplasia. Some MUC-type mucins have emerged as valuable prognostic indicators in pleomorphic adenoma, mucoepidermoid carcinoma and HNSCC. Nine antibodies directed against different MUC1 antigens have thus far been examined in HNSCC of which monoclonal antibodies DF3, HMFG-1 and Ma695 have shown significant correlations with disease outcome. The importance of taking the specific anti-MUC antibody into consideration when comparing the results of different studies on MUC expression in salivary gland tumors and HNSCC is also highlighted in this review.

Carrara S, Cangi MG, Arcidiacono PG, et al.
Mucin expression pattern in pancreatic diseases: findings from EUS-guided fine-needle aspiration biopsies.
Am J Gastroenterol. 2011; 106(7):1359-63 [PubMed] Related Publications
OBJECTIVES: Alterations in mucin (MUC) glycosylation and expression have been described in cancer. Endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) can provide material for molecular biology analysis. This study assessed the feasibility of evaluating MUC expression from material obtained by EUS-FNA and studied the profile of MUC expression in benign and malignant pancreatic lesions.
METHODS: A total of 90 patients with solid or cystic pancreatic lesions underwent FNA. The aspirated material was used for cytological analysis and RNA extraction to assess the expression pattern of MUCs by reverse transcription-PCR with primers specific for the MUC1, MUC2, MUC3, MUC4, MUC5A, MUC5B, MUC6, and MUC7 genes.
RESULTS: RNA extraction was successful in 81% of the biopsies. The prevalences of MUC1, MUC2, MUC4, and MUC7 in ductal adenocarcinoma were 57.7, 51.4, 18.9, and 73.0%, respectively. Fifty percent of benign lesions and neuroendocrine tumors (NETs), and 63% of intraductal papillary mucinous neoplasms (IPMNs) were positive for MUC1. Twenty-five percent of benign lesions, 86% of NETs, and 47% of IPMNs were positive for MUC2. Of NETs, 50% were positive for MUC1, and 14% were positive for MUC7. None of the benign lesions or NETs expressed MUC4. MUC7 expression was highly significant for adenocarcinoma (P=0.007) and borderline for IPMN (P=0.05). MUC7 was expressed in 37.5% of chronic pancreatitis cases.
CONCLUSIONS: RNA can be extracted from samples obtained under EUS-FNA. MUC7 could serve as a potential biological marker to identify malignant lesions, especially pancreatic adenocarcinoma.

Kitamoto S, Yamada N, Yokoyama S, et al.
DNA methylation and histone H3-K9 modifications contribute to MUC17 expression.
Glycobiology. 2011; 21(2):247-56 [PubMed] Free Access to Full Article Related Publications
MUC17 glycoprotein is a membrane-associated mucin that is mainly expressed in the digestive tract. It has been suggested that MUC17 expression is correlated with the malignancy potential of pancreatic ductal adenocarcinomas (PDACs). In the present study, we provided the first report of the MUC17 gene expression through epigenetic regulation such as promoter methylation, histone modification and microRNA (miRNA) expression. Near the transcriptional start site, the DNA methylation level of MUC17-negative cancer cell lines (e.g. PANC1) was high, whereas that of MUC17-positive cells (e.g. AsPC-1) was low. Histone H3-K9 (H3-K9) modification status was also closely related to MUC17 expression. Our results indicate that DNA methylation and histone H3-K9 modification in the 5' flanking region play a critical role in MUC17 expression. Furthermore, the hypomethylation status was observed in patients with PDAC. This indicates that the hypomethylation status in the MUC17 promoter could be a novel epigenetic marker for the diagnosis of PDAC. In addition, the result of miRNA microarray analysis showed that five potential miRNA candidates existed. It is also possible that the MUC17 might be post-transcriptionally regulated by miRNA targeting to the 3'-untranslated region of its mRNA. These understandings of the epigenetic changes of MUC17 may be of importance for the diagnosis of carcinogenic risk and the prediction of outcomes for cancer patients.

Kim YS, Ho SB
Intestinal goblet cells and mucins in health and disease: recent insights and progress.
Curr Gastroenterol Rep. 2010; 12(5):319-30 [PubMed] Free Access to Full Article Related Publications
The mucus layer coating the gastrointestinal tract is the front line of innate host defense, largely because of the secretory products of intestinal goblet cells. Goblet cells synthesize secretory mucin glycoproteins (MUC2) and bioactive molecules such as epithelial membrane-bound mucins (MUC1, MUC3, MUC17), trefoil factor peptides (TFF), resistin-like molecule beta (RELMbeta), and Fc-gamma binding protein (Fcgbp). The MUC2 mucin protein forms trimers by disulfide bonding in cysteine-rich amino terminal von Willebrand factor (vWF) domains, coupled with crosslinking provided by TFF and Fcgbp proteins with MUC2 vWF domains, resulting in a highly viscous extracellular layer. Colonization by commensal intestinal microbiota is limited to an outer "loose" mucus layer, and interacts with the diverse oligosaccharides of mucin glycoproteins, whereas an "inner" adherent mucus layer is largely devoid of bacteria. Defective mucus layers resulting from lack of MUC2 mucin, mutated Muc2 mucin vWF domains, or from deletion of core mucin glycosyltransferase enzymes in mice result in increased bacterial adhesion to the surface epithelium, increased intestinal permeability, and enhanced susceptibility to colitis caused by dextran sodium sulfate. Changes in mucin gene expression and mucin glycan structures occur in cancers of the intestine, contributing to diverse biologic properties involved in the development and progression of cancer. Further research is needed on identification and functional significance of various components of mucus layers and the complex interactions among mucus layers, microbiota, epithelial cells, and the underlying innate and adaptive immunity. Further elucidation of the regulatory mechanisms involved in mucin changes in cancer and inflammation may lead to the development of novel therapeutic approaches.

Hirono S, Yamaue H, Hoshikawa Y, et al.
Molecular markers associated with lymph node metastasis in pancreatic ductal adenocarcinoma by genome-wide expression profiling.
Cancer Sci. 2010; 101(1):259-66 [PubMed] Related Publications
Lymph node metastasis (LNM) is the most important prognostic factor in patients undergoing surgical resection of pancreatic ductal adenocarcinoma (PDAC). In this study, we aimed to identify molecular markers associated with LNM in PDAC using genome-wide expression profiling. In this study, laser microdissection and genome-wide transcriptional profiling were used to identify genes that were differentially expressed between PDAC cells with and without LNM obtained from 20 patients with PDAC. Immunohistochemical staining was used to confirm the clinical significance of these markers in an additional validation set of 43 patients. In the results, microarray profiling identified 46 genes that were differently expressed between PDAC with and without LNM with certain significance. Four of these biomarkers were validated by immunohistochemical staining for association with LNM in PDAC in an additional validation set of patients. In 63 patients with PDAC, significant LNM predictors in PDAC elucidated from multivariate analysis were low expression of activating enhancer binding protein 2 (AP2alpha) (P = 0.012) and high expression of mucin 17 (MUC17) (P = 0.0192). Furthermore, multivariate analysis revealed that AP2alpha-low expression and MUC17-high expression are independent prognostic factors for poor overall survival (P = 0.0012, 0.0001, respectively). In conclusion, AP2alpha and MUC17 were independent markers associated with LNM of PDAC. These two markers were also associated with survival in patients with resected PDAC. We demonstrate that AP2alpha and MUC17 may serve as potential prognostic molecular markers for LNM in patients with PDAC.

Ou G, Baranov V, Lundmark E, et al.
Contribution of intestinal epithelial cells to innate immunity of the human gut--studies on polarized monolayers of colon carcinoma cells.
Scand J Immunol. 2009; 69(2):150-61 [PubMed] Related Publications
The aim was to establish an in vitro model for studies of innate defence mechanisms of human intestinal epithelium. Ultrastructural characterization and determination of mRNA expression levels for apical glycocalyx and mucous components showed that polarized, tight monolayers of the colon carcinoma cell lines T84 and Caco2 acquire the features of mature- and immature columnar epithelial cells, respectively. Polarized monolayers were challenged with non-pathogenic Gram+ and Gram- bacteria from the apical side and the proinflammatory cytokines interferon-gamma (IFN-gamma), tumour necrosis factor-alpha (TNF-alpha) and interleukin-1beta (IL-1beta) from the basolateral side. Immune responses were estimated as changes in mRNA expression levels for the mucous component mucin-2 (MUC2), the glycocalyx components carcinoembryonic antigen (CEA), CEA-related cell adhesion molecule-1 (CEACAM1), CEACAM6, CEACAM7 and MUC3, the antimicrobial factors human beta-defensin-1 (hBD1), hBD2, hBD3 and lysozyme, the chemokine IL-8 and the cytokines IL-6 and TNF-alpha. Tight monolayer cells were generally unresponsive to bacterial challenge, but increased their hBD2 levels when challenged with Bacillus megaterium. T84 cells also increased their TNF-alpha levels upon bacterial challenge. Tight monolayer cells responded to cytokine challenge suggesting awareness of basolateral attack. TNF-alpha induced significantly increased levels of IL-8 and TNF-alpha itself in both cell lines suggesting recruitment and activation of immune cells in the underlying mucosa in vivo. Cytokine challenge also increased levels of CEACAM1, which includes two functionally different forms, CEACAM1-L and CEACAM1-S. In T84 cells, IFN-gamma was selective for CEACAM1-L while TNF-alpha upregulated both forms. Increased CEACAM1 expression may influence epithelial function and communication between epithelial cells and intraepithelial lymphocytes.

Rouzbahman M, Serra S, Adsay NV, et al.
Oncocytic papillary neoplasms of the biliary tract: a clinicopathological, mucin core and Wnt pathway protein analysis of four cases.
Pathology. 2007; 39(4):413-8 [PubMed] Related Publications
AIMS: Oncocytic change in papillary neoplasms of the biliary tract is a very uncommon finding with little known about pathogenesis, immunophenotype and prognosis, especially in comparison to similar lesions in the pancreatic ductal system. We report four cases of oncocytic biliary intraductal papillary neoplasms (IPNs), highlighting the clinicopathological characteristics of these tumours, the immunohistochemical profile with regard to Wnt pathway proteins and mucin core protein (MUC) status, and compare these findings with the oncocytic variant of intraductal papillary mucinous neoplasm (IPMN) of the pancreas.
METHODS: Four cases of oncocytic IPN of the extrapancreatic, biliary tree (two with accompanying invasive carcinomas) were examined for mucin profiles and Wnt signalling proteins. The cases were stained for: beta-catenin, c-myc, glutathione synthase kinase (GSK), E-cadherin, cyclin D1, and adenomatous polyposis coli (APC), and MUC1, MUC2, MUC3, MUC4, MUC5AC, MUC5B and MUC6, using standard immunohistochemistry.
RESULTS: The cases occurred in three males and one female, ranging in age from 59 to 81 years. The lesions caused obstructive symptoms related to the biliary tree as well as non-specific abdominal symptoms. Typically, cystic lesions were noted grossly. All four of the IPNs were composed of distinctive oncocytic cells. The invasive carcinomas accompanying two of the cases were also composed of oncocytes. None of the cases showed aberrant expression of the Wnt signalling proteins, although cyclin D1 was markedly over-expressed in all four cases. Three of four cases showed the following mucin profile: MUC3, MUC4, MUC5AC, MUC5B and MUC6 positive.
CONCLUSIONS: The Wnt pathway proteins (especially beta-catenin and E-cadherin) are expressed normally in oncocytic variants of intraductal papillary neoplasms of the biliary tree, and the mucin profile is similar to their counterparts in the pancreas.

Duncan TJ, Watson NF, Al-Attar AH, et al.
The role of MUC1 and MUC3 in the biology and prognosis of colorectal cancer.
World J Surg Oncol. 2007; 5:31 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: MUC1 and MUC3 are from a large family of glycoproteins with an aberrant expression profile in various malignancies. Much interest has been focused on the role of these proteins in the development and progression of colorectal cancer; however, no previous studies have included the highly confounding variable of vascular invasion in their survival analysis. Using high throughput tissue microarray technology we assessed the prognostic value of MUC1 and MUC3 expression in the largest cohort of colorectal cancer patients to date. We propose that tumours lacking expression of MUC1 and MUC3 will be more likely to metastasise, due to previously observed loss of cell-cell adhesion, and this will therefore lead to more aggressive cancers with poorer prognosis.
METHODS: A tissue micro-array was prepared from tumour samples of 462 consecutive patients undergoing resection of a primary colorectal cancer. A comprehensive prospectively recorded data base with mean follow up of 75 months was collected and included common clinicopathological variables and disease specific survival. Immunohistochemical analysis of MUC1 and MUC3 expression was performed using antibodies NCL-MUC1 and 1143/B7 respectively, results were correlated with the variables within the database.
RESULTS: Positive expression of MUC1 and MUC3 was seen in 32% and 74% of tumours respectively. On univariate analysis no correlation was seen with either MUC1 or MUC3 and any of the clinicopathological variables including tumour grade and stage, vascular invasion and tumour type. Kaplan-Meier analysis demonstrated a significant reduction in disease specific survival with MUC1 positive tumours (p = 0.038), this was not seen with MUC3 (p = 0.552). On multivariate analysis, using Cox proportional hazards model, MUC1 expression was shown to be an independent marker of prognosis (HR 1.339, 95%CI 1.002-1.790, p = 0.048).
CONCLUSION: MUC1 expression in colorectal cancer is an independent marker of poor prognosis, even when vascular invasion is included in the analysis. These results support previous studies suggesting a role for MUC1 in colorectal cancer development possibly through its effects on cell adhesion.

Abba MC, Nunez MI, Colussi AG, et al.
GATA3 protein as a MUC1 transcriptional regulator in breast cancer cells.
Breast Cancer Res. 2006; 8(6):R64 [PubMed] Free Access to Full Article Related Publications
INTRODUCTION: Recent studies have demonstrated that members of the GATA-binding protein (GATA) family (GATA4 and GATA5) might have pivotal roles in the transcriptional upregulation of mucin genes (MUC2, MUC3 and MUC4) in gastrointestinal epithelium. The zinc-finger GATA3 transcription factor has been reported to be involved in the growth control and differentiation of breast epithelial cells. In SAGE (serial analysis of gene expression) studies we observed an intriguing significant correlation between GATA3 and MUC1 mRNA expression in breast carcinomas. We therefore designed the present study to elucidate whether MUC1 expression is regulated by GATA3 in breast cancer cells.
METHODS: Promoter sequence analysis of the MUC1 gene identified six GATA cis consensus elements in the 5' flanking region (GATA1, GATA3 and four GATA-like sequences). Chromatin immunoprecipitation and electrophoretic mobility-shift assays were employed to study the presence of a functional GATA3-binding site. GATA3 and MUC1 expression was analyzed in vitro with a GATA3 knockdown assay. Furthermore, expression of GATA3 and MUC1 genes was analyzed by real-time RT-PCR and immunohistochemistry on breast cancer-specific tissue microarrays.
RESULTS: We confirmed the presence of a functional GATA3-binding site on the MUC1 promoter region in the MCF7 cell line. We determined that GATA3 knockdown assays led to a decrease in MUC1 protein expression in MCF7 and T47D cells. In addition, we detected a statistically significant correlation in expression between GATA3 and MUC1 genes at the mRNA and protein levels both in normal breast epithelium and in breast carcinomas (p = 0.01). GATA3 expression was also highly associated with estrogen receptor and progesterone receptor status (p = 0.0001) and tumor grade (p = 0.004) in breast carcinomas.
CONCLUSION: Our study provides evidence indicating that GATA3 is probably a mediator for the transcriptional upregulation of MUC1 expression in some breast cancers.

You JF, Hsieh LL, Changchien CR, et al.
Inverse effects of mucin on survival of matched hereditary nonpolyposis colorectal cancer and sporadic colorectal cancer patients.
Clin Cancer Res. 2006; 12(14 Pt 1):4244-50 [PubMed] Related Publications
PURPOSE: To compare survival and histologic features of hereditary nonpolyposis colorectal cancer (HNPCC; Lynch syndrome) cases to well-matched sporadic colon cancers from the same patient population.
EXPERIMENTAL DESIGN: Between January 1995 and March 2002, a total of 5,138 consecutive patients underwent resection of primary colorectal adenocarcinoma in a single institution. According to the Amsterdam criteria, 56 HNPCC patients were matched to 147 sporadic colorectal cancer (SCRC) with no family history of cancer and with the same gender, tumor location, and age within 3 years. Immunohistochemical analyses were done for MUC1, MUC2, MUC3, and MUC5AC.
RESULTS: The HNPCC group had a marginally significantly better long-term outcome than the SCRC group (P = 0.058). The trend disappeared after adjustment by tumor-node-metastasis stage in a Cox model (P = 0.774). We noted a difference of >50% in the 5-year cancer-specific survival rates of HNPCC- and SCRC-mucinous groups (92% versus 31%, P = 0.0003). Interaction between mucin and HNPCC and its effects on survival were further confirmed by comparing the Cox models with and without interaction terms (hazard ratio, 0.1; P = 0.034 with adjusting stage). Patients with tumors showing dual expression of mucin and MUC1, which appeared in 11% of those with HNPCC and 50% of those with SCRC, had a lower 5-year cancer-specific survival rate than patients without (30% versus 60%; P = 0.004 by log-rank test; P = 0.039 with adjustment for tumor-node-metastasis stage).
CONCLUSIONS: These results suggest that mucin has an inverse effect on survival in patients with HNPCC and SCRC, which might be partly explained by a lower prevalence of MUC1 expression in the mucinous HNPCC group than in the SCRC groups.

Moniaux N, Junker WM, Singh AP, et al.
Characterization of human mucin MUC17. Complete coding sequence and organization.
J Biol Chem. 2006; 281(33):23676-85 [PubMed] Related Publications
With increasing interest on mucins as diagnostic and therapeutic targets in cancers and other diseases, it is becoming imperative to characterize novel mucins and investigate their biological significance. Here, we present the completed coding sequence and genomic organization of the previously published partial cDNA sequence of MUC17. Rapid amplification of cDNA ends with PCR, sequences from the Human Genome databases, and in vitro transcription/translational assays were used for these analyses. The MUC17 gene is located within a 39-kb DNA fragment between MUC12 and SERPINE1 on chromosome 7 in the region q22.1. The full-length coding sequence of MUC17 transcribes a 14.2-kb mRNA encompassing 13 exons. Alternate splicing generates two variants coding for a membrane-anchored and a secreted form. The canonical variable number of tandem repeats polymorphism of the central tandem repeat domain of the MUC genes is not significantly detected in the MUC17 gene. In addition, we show the overexpression of MUC17 by Western blot and immunohistochemical analyses in pancreatic tumor cell lines and tumor tissues compared with the normal pancreas. The expression of MUC17 is regulated by a 1,146-bp fragment upstream of MUC17 that contains VDR/RXR, GATA, NFkappaB, and Cdx-2 response elements.

Sóñora C, Mazal D, Berois N, et al.
Immunohistochemical analysis of MUC5B apomucin expression in breast cancer and non-malignant breast tissues.
J Histochem Cytochem. 2006; 54(3):289-99 [PubMed] Related Publications
A deregulation of several MUC genes (MUC1, MUC2, MUC3, MUC5AC, and MUC6) was previously demonstrated in breast carcinomas. Considering that recently we found the "non-mammary" MUC5B mRNA in primary breast tumors (Berois et al. 2003), we undertook the present study to evaluate the expression profile of MUC5B protein product in breast tissues, using LUM5B-2 antisera raised against sequences within the non-glycosylated regions of this apomucin. Expression of MUC5B by breast cancer cells was confirmed by immunocytochemistry, in situ hybridization, and Western blot on MCF-7 cancer cells. Using an immunohistochemical procedure, MUC5B apomucin was detected in 34/42 (81%) primary breast tumors, in 13/14 (92.8%) samples of non-malignant breast diseases, in 8/19 (42.1%) samples of normal-appearing breast epithelia adjacent to cancer, and in 0/5 normal control breast samples. The staining pattern of MUC5B was very different when comparing breast cancer cells (cytoplasmic) and non-malignant breast cells (predominantly apical and in the secretory material). We analyzed MUC5B mRNA expression using RT-PCR in bone marrow aspirates from 22/42 patients with breast cancer to compare with MUC5B protein expression in the primary tumors. Good correlation was observed because the six MUC5B-positive bone marrow samples also displayed MUC5B expression in the tumor. Our results show, for the first time at the protein level, that MUC5B apomucin is upregulated in breast cancer. Its characterization could provide new insights about the glycobiology of breast cancer cells.

Packer LM, Williams SJ, Callaghan S, et al.
Expression of the cell surface mucin gene family in adenocarcinomas.
Int J Oncol. 2004; 25(4):1119-26 [PubMed] Related Publications
Cell surface mucins are complex glycoproteins expressed on the apical membrane surface of mucosal epithelial cells. In malignant epithelial cells they are thought to influence cell adhesion, and are clinical targets for tumor immunotherapy and serum tumor marker assays. We have compared expression of MUC1, MUC3, MUC4, MUC11, MUC12 and MUC13 mRNA in epithelial cancers and/or cell lines with non-malignant tissues. In non-malignant tissues, MUC3, 4, 11, 12 and 13 were expressed at highest levels in gastrointestinal tissues, whereas MUC1 was more widely distributed. Significant down-regulation of the MUC4, MUC12 and MUC13 genes was observed in colonic cancers compared with normal tissue, whereas MUC1 was upregulated. In rectal cancers, levels of all six mucin genes were not significantly different to those in normal rectal tissues. Both MUC1 and MUC4 were down-regulated in gastric cancers, whereas cancer and normal tissue levels were similar for MUC3, 11, 12 and 13. In esophageal cancers there was a general trend toward higher levels than in normal tissue for MUC1, 3, 12 and 13. In ovarian cancers MUC1 levels were very high, whereas only low levels of all other mucins were observed. We also report expression in renal cell carcinomas, bladder carcinomas and breast cancer cell lines. The reported expression profiles of the cell surface mucin gene family will help direct biological and clinical studies of these molecules in mucosal biology, and in malignant and inflammatory diseases of epithelial tissues.

Paleri V, Pearson JP, Bulmer D, et al.
Expression of mucin gene products in laryngeal squamous cancer.
Otolaryngol Head Neck Surg. 2004; 131(1):84-8 [PubMed] Related Publications
OBJECTIVE: Mucins are high-molecular-weight glycoproteins present at the outer surface of mammalian cells. The objective of this study was to examine the expression of mucin (MUC) genes 3, 4, 5AC, 5B, 6, and 7 in early and late laryngeal squamous cancer using the in situ hybridization technique. Study design Retrospective analysis of pathological archive specimens.
RESULTS: While MUC 3 and 7 are expressed in a small proportion of early cancers, MUC 5AC, 5B, and 6 are not expressed in laryngeal squamous cancer. MUC 4 was expressed in 13 of the 30 patients. Ten patients and 3 patients with stage 1 and stage 4 disease respectively expressed MUC 4 gene (Fisher's exact, P = 0.02). MUC 4-positive patients had a definite trend towards better survival (log rank test, P = 0.05). In the presence of tumor stage and comorbidity grade, Cox's proportional hazards model failed to statistically confirm the survival advantage provided by MUC 4 gene expression.
CONCLUSION: There is a survival advantage for patients with advanced-stage nonmetastatic cancer when the MUC 4 gene is expressed.
AIMS: To study the expression of mucin (MUC) genes 3, 4, 5AC, 5B, 6, and 7 in early and advanced squamous cell cancer of the larynx; to attempt to correlate changes in gene expression with tumor stage by studying stage I and stage IV (AJCC, 1988) tumors.

Byrd JC, Bresalier RS
Mucins and mucin binding proteins in colorectal cancer.
Cancer Metastasis Rev. 2004 Jan-Jun; 23(1-2):77-99 [PubMed] Related Publications
Mucins are high-molecular weight epithelial glycoproteins with a high content of clustered oligosaccharides O-glycosidically linked to tandem repeat peptides rich in threonine, serine, and proline. There are two structurally and functionally distinct classes of mucins: secreted gel-forming mucins (MUC2, MUC5AC, MUC5B, and MUC6) and transmembrane mucins (MUC1, MUC3A, MUC3B, MUC4, MUC12, MUC17), although the products of some MUC genes do not fit well into either class (MUC7, MUC8, MUC9, MUC13, MUC15, MUC16). MUC1 mucin, as detected immunologically, is increased in expression in colon cancers, which correlates with a worse prognosis. Expression of MUC2 secreted gel-forming mucin is generally decreased in colorectal adenocarcinoma, but preserved in mucinous carcinomas, a distinct subtype of colon cancer associated with microsatellite instability. Another secreted gel-forming mucin, MUC5AC, a product of normal gastric mucosa, is absent from normal colon, but frequently present in colorectal adenomas and colon cancers. The O-glycosidically linked oligosaccharides of mucins can be described in terms of core type, backbone type, and peripheral structures. Colon cancer mucins have differences in both core carbohydrates and in peripheral carbohydrate structures that are being investigated as diagnostic and prognostic markers, and also as targets for cancer vaccines. Colon cancer mucins typically have increases in three core structures: Tn antigen (GalNAcalphaThr/Ser), TF antigen (Galbeta3GalNAc) and sialyl Tn (NeuAcalpha6GalNAc). The type 3 core (GlcNAcbeta3Ga1NAc) predominant in normal colonic mucin is lacking in colon cancer mucins. There are cancer-associated alterations in the peripheral carbohydrates of colonic mucins including a decrease in O-acetyl-sialic acid and a decrease in sulfation. There are, however, cancer-associated increases in sialyl LeX and related structures on mucins and other glycoproteins that can serve as ligands for selectins, increasing the metastatic capacity of colon cancer cells. The endogenous galactoside-binding protein galectin-3, which is expressed at higher levels in colon cancers than normal colon, binds to colon cancer mucin as well as other glycoproteins. Interference of the binding of selectins and galectin-3 to mucin may show therapeutic or preventative promise for colon cancer.

Leroy X, Gouyer V, Ballereau C, et al.
Quantitative RT-PCR assay for MUC3 and VEGF mRNA in renal clear cell carcinoma: relationship with nuclear grade and prognosis.
Urology. 2003; 62(4):771-5 [PubMed] Related Publications
OBJECTIVES: To investigate, by real-time quantitative reverse transcriptase-polymerase chain reaction, the expression of MUC3 and vascular endothelial growth factor (VEGF) to correlate them with histologic parameters and with prognosis. Human mucins are large O-glycoproteins expressed in epithelial tissues. Deregulation of mucin genes has been demonstrated in several epithelial neoplasms. In the kidney, MUC3 is expressed in normal convoluted tubules and in renal clear cell carcinoma.
METHODS: Twenty-six renal clear cell carcinoma specimens were studied. For all tumors, samples of normal and tumor kidney were frozen. After RNA extraction, using ultracentrifugation through a cesium chloride cushion, VEGF and MUC3 mRNA were analyzed by real-time quantitative reverse transcriptase-polymerase chain reaction. The pathologic parameters included Fuhrman nuclear grade and TNM stage. All follow-up data were available.
RESULTS: The median level of MUC3 and VEGF expression was greater in tumor areas compared with normal areas (P < 0.002 and P < 0.001, respectively). The MUC3 tumor/normal tissue expression ratio was greater in nuclear grade 3 tumor than in low grades (grade 1-2; P < 0.005). No statistically significant relationship was found with the prognosis for MUC3 and VEGF in our study.
CONCLUSIONS: The results of this study demonstrate that MUC3 and VEGF are overexpressed in renal clear cell carcinoma, and the MUC3 expression ratio is greater in nuclear grade 3 than in grades 1 and 2 (low grades) tumor. These findings suggest the implication of MUC3 in renal carcinogenesis.

Shekels LL, Ho SB
Characterization of the mouse Muc3 membrane bound intestinal mucin 5' coding and promoter regions: regulation by inflammatory cytokines.
Biochim Biophys Acta. 2003; 1627(2-3):90-100 [PubMed] Related Publications
The mouse Muc3 mucin is a membrane-bound glycoprotein highly expressed in the intestinal tract. We have characterized the mouse Muc3 5' structure and regulation of its promoter by cytokines and growth factors. The first two exons of Muc3 are separated by an intron of over 8 kb. Exon 3 contains the tandem repeat domain. Ten exons reside 3' to the tandem repeat domain. The 5' nonrepetitive sequence contains 104 amino acids characterized by a putative signal sequence, a single cysteine and 28% serine/threonine. No TATA box is found near the transcription start site. The promoter has consensus binding sites for AP1, CREB, SP1, NF kappa B, GATA binding protein and Cdx. Muc3 promoter constructs demonstrate that IL4, IL6, EGF or PMA increased promoter activity to 35-58% of control. TNF alpha and IFN gamma showed lesser stimulation. These data indicate that cytokines and growth factors are capable of regulating Muc3 gene expression, suggesting that this protein may play an active role in intestinal mucosal defense.

Park HU, Kim JW, Kim GE, et al.
Aberrant expression of MUC3 and MUC4 membrane-associated mucins and sialyl Le(x) antigen in pancreatic intraepithelial neoplasia.
Pancreas. 2003; 26(3):e48-54 [PubMed] Related Publications
INTRODUCTION: Ductal adenocarcinoma of the pancreas has recently been suggested to arise from histologically identifiable ductal lesions known as pancreatic intraepithelial neoplasia (PanINs). Altered levels and patterns of mucin gene expression have been reported to occur in epithelial cancers.
AIM: To examine the pattern of expression of membrane-associated mucins, MUC3 and MUC4, and a mucin-associated carbohydrate tumor antigen, sialyl Le(x), in these precursor lesions and ductal adenocarcinoma of the pancreas.
METHODOLOGY: A total of 144 PanIN lesions and 85 cases of ductal adenocarcinoma of the pancreas were examined by using immunohistochemistry and in situ hybridization methods.
RESULTS: MUC3 showed a progressive increase in expression in PanINs of increasing dysplasia and was also highly expressed in ductal adenocarcinoma. In contrast, neoexpression of MUC4 and sialyl Le(x) antigen was observed, mainly in PanIN-3 and ductal adenocarcinoma. In addition, a decrease in the expression of MUC3 and MUC4 was correlated with the degree of de-differentiation of the tumor.
CONCLUSION: Aberrant expression of membrane mucins MUC3 and MUC4 and of a mucin-associated carbohydrate tumor antigen Sialyl Le(x) in PanINs and adenocarcinoma further supports the progression model for pancreatic adenocarcinoma.

Berois N, Varangot M, Sóñora C, et al.
Detection of bone marrow-disseminated breast cancer cells using an RT-PCR assay of MUC5B mRNA.
Int J Cancer. 2003; 103(4):550-5 [PubMed] Related Publications
The evaluation of disseminated epithelial tumor cells in breast cancer patients has generated considerable interest due to its potential association with disease recurrence. Our work was performed to analyze the usefulness of 5 mucin genes expression (MUC2, MUC3, MUC5B, MUC6 and MUC7), using RT-PCR assays, to detect disseminated cancer cells in patients with operable breast cancer. The highest frequencies of positive RT-PCR tests in breast tumor extracts were observed for MUC5B (7/15) and MUC7 (5/12). The best specificity, negative results on all peripheral blood mononuclear (PBMN) cell samples from healthy donors, were shown for MUC2, MUC5B and MUC6 RT-PCR assays. Thus, we selected MUC5B as a target gene for further evaluation. Using a nested RT-PCR, MUC5B mRNA transcripts were detected in 16/31 primary breast tumors (but not in 36 samples of normal PBMN cells) and in the human MCF-7 breast cancer cell line but not in BT20, MDA, T47D and ZR-75 breast cancer cell lines, indicating that MUC5B mRNA is expressed in a population of breast cancer cells. Using this method, 9/46 patients (19.5%) who underwent curative surgery showed positive MUC5B mRNA in bone marrow aspirates obtained prior to surgery, including 5/24 patients (20.8%) with stage I or II breast cancer, without histopathologic lymph node involvement. These results indicate that MUC5B mRNA could be a specific marker applicable to the molecular diagnosis of breast cancer cell dissemination. A comparative evaluation between MUC5B mRNA, cytokeratin 19 (CK19) mRNA and carcinoembryonic antigen (CEA) mRNA in all bone marrow aspirates suggests a putative complementation for molecular detection of disseminated carcinoma cells. Considering that breast cancer is characterized by a great phenotypic heterogeneity, the use of multimarker approach could contribute to tumor cell detection in bone marrow and blood.

Terris B, Dubois S, Buisine MP, et al.
Mucin gene expression in intraductal papillary-mucinous pancreatic tumours and related lesions.
J Pathol. 2002; 197(5):632-7 [PubMed] Related Publications
Intraductal papillary-mucinous tumours (IPMTs) of the pancreas are heterogeneous proliferations characterized by a malignant potential. The molecular mechanisms underlying the tumourigenesis process are not well understood. Recently, it has been shown that IPMTs secreting the mucin antigen MUC2 have a better prognosis, but the complete pattern of MUC gene expression has not yet been established. The aims of this study were to evaluate the mucin gene expression in 57 IPMTs and eight related lesions surgically resected and to relate MUC gene expression to the histological diagnosis. In situ hybridization (ISH) was performed in 28 cases with probes specific for the MUC1, MUC2, MUC3, MUC4, MUC5AC, MUC5B, MUC6, and MUC7 genes. An immunohistochemical analysis was carried in all 65 cases and in 90 conventional ductal adenocarcinomas of the pancreas using MUC1, MUC2, and MUC5AC antibodies. IPMTs of adenoma (dysplasia) type exhibited high expression of MUC2 (93%), MUC5AC (97%), and, to a lesser extent, of MUC4 (71%), all of which were also observed in colloid carcinomas associated with IPMTs. In contrast, IPMTs with simple hyperplasia, intraductal oncocytic papillary neoplasms, and pyloric glandular adenomas exhibited little or no expression of MUC2. The mucin expression profile supports the existence of two types of invasive tumour associated with IPMTs: a colloid and an ordinary form. The latter shows a pattern similar to the conventional ductal adenocarcinomas with a loss of MUC2 and a gain of MUC1 and has a greater tendency to metastasize. In conclusion, the altered expression of mucin, characteristic of IPMT of adenoma type and of colloid carcinomas, may contribute to the better clinical outcome of these neoplasms, compared to conventional pancreatic ductal adenocarcinomas.

Sylvester PA, Walsh M, Myerscough N, et al.
Mucin gene expression in the ileoanal reservoir is altered and may be relevant to the risk of inflammation and dysplasia.
Gut. 2002; 51(3):386-91 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: Adaptive colonic phenotypic change of the ileal mucosa is a feature of the ileoanal reservoir (IAR) with time, as described by mucin glycoprotein and histological analysis. Mucin gene expression is altered in colorectal neoplasia and inflammatory bowel disease but little is known of its expression in the IAR.
AIMS: To examine the changes in mucin gene expression contributing to mucosal protection of the IAR against a background of known changes occurring in inflammatory disease and colorectal neoplasia.
PATIENTS: Paraffin embedded specimens from 29 "W" and 11 "J" ileoanal reservoirs were studied. Colonic and ileal control tissue was obtained from normal resection margins.
METHODS: Mucin mRNA was detected by in situ hybridisation using [(35)S]dATP labelled oligonucleotide probes. Mucin core protein was detected by immunohistochemistry.
RESULTS: There was no change in mRNA expression of MUC1-4 in the IAR compared with ileal controls but there was a decrease in the protein product of MUC1 and MUC3. No mRNA transcripts of MUC5AC, 5B, or 6 were detected but protein product of MUC5AC and MUC6 was detected. Both cases of MUC6 positivity and 1/5 cases of MUC5AC positivity were confined to the ulcer associated cell lineage. No dysplasia was detected.
CONCLUSIONS: There is a change in the pattern of the membrane associated mucins MUC1 and MUC3, part of which is in keeping with changes described in colorectal neoplasia. A small number of cases demonstrated mucin gene changes (MUC5AC) which are seen in early neoplasia and this may provide a valuable monitor for such changes in IAR surveillance.

Leroy X, Copin MC, Devisme L, et al.
Expression of human mucin genes in normal kidney and renal cell carcinoma.
Histopathology. 2002; 40(5):450-7 [PubMed] Related Publications
AIMS: Human mucins are large O-glycoproteins expressed by epithelial cells. Mucins are thought to be implicated in cell protection, cell adhesion and signalling. The aim of this study was to investigate the expression of the human mucin genes (MUC1-4, 5AC, 5B, 6-7) in normal kidney and renal cell carcinoma.
METHODS AND RESULTS: We analysed by in-situ hybridization, immunohistochemistry and reverse transcriptase-polymerase chain reaction (RT-PCR) the expression of these genes in normal adult kidney (n=14) and renal cell carcinomas (n=29). MUC1, MUC3 and MUC6 were expressed both in normal kidney and in renal carcinomas. In normal kidney, MUC1 was expressed in the distal convoluted tubules and in collecting ducts, whereas MUC3 was restricted to the proximal tubules. MUC4 was strongly expressed in epithelial urothelial cells of pyelocalyceal cavities. MUC6 was only detected by RT-PCR. In renal carcinoma, we showed a heterogeneous expression of MUC1 and MUC3 with an over-expression of MUC3 in renal clear cell carcinoma. The level of MUC3 expression by in-situ hybridization was associated with the nuclear grade in clear cell carcinoma.
CONCLUSIONS: This study is the first large series investigating human mucin gene expression in the kidney. MUC1, MUC3 and MUC6 are expressed in normal and tumour kidney. The over-expression of MUC3 in renal cell carcinomas favours its implication in renal tumorigenesis.

Gum JR, Crawley SC, Hicks JW, et al.
MUC17, a novel membrane-tethered mucin.
Biochem Biophys Res Commun. 2002; 291(3):466-75 [PubMed] Related Publications
Membrane mucins have several functions in epithelial cells including cytoprotection, extravasation during metastases, maintenance of luminal structure, and signal transduction. In this paper we describe a large membrane mucin expressed in the normal intestine. This novel mucin, designated MUC17, contains an extended, repetitive extracellular glycosylation domain and a carboxyl terminus with two EGF-like domains, a SEA module domain, a transmembrane domain, and a cytoplasmic domain with potential serine and tyrosine phosphorylation sites. RNA blot analysis and in situ hybridization indicates that MUC17 is expressed in select pancreatic and colon cancer cell lines and in intestinal absorptive cells. Radiation hybrid mapping localized MUC17 to chromosome 7q22 where it resides in close proximity with three other membrane mucin genes, MUC3A, MUC3B, and MUC12. Thus, these membrane mucins reside together in a gene cluster, but are expressed in different tissues and are likely to have different functions as well.

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