Tear film instability is associated with weakened colocalization between occludin and MUC5AC in scopolamine-induced dry eye disease (DED) rats.

PURPOSE: Dry eye disease (DED) is a disease with tear film instability because of multiple factors. This study was conducted to explore roles of occludin and MUC5AC in tear film instability in DED rat model. METHODS: A total of 20 SD rats were divided into DED group (n = 10) and normal control (NC) group (n = 10). DED rat model was established by subcutaneously injecting with scopolamine hydrobromide. Clinical examinations, including tear breakup time (tBUT), Schirmer's test and corneal fluorescein staining, were conducted to determine corneal functions. Transmission electron microscopy was used to measure the ultrastructures of corneal epithelial cells. Western blotting assay was used to identify occludin expression in corneal tissues of DED rats. Real-time PCR (RT-PCR) was performed to verify gene transcription of occludin and MUC5AC. Colocalization between occludin and MUC5AC was identified with confocal fluorescence microscopy. RESULTS: Tear breakup time was significantly shorter, and corneal fluorescein staining score was predominantly higher in DED rats compared to those in normal rats (P < 0.05). Normal rats showed a steady tear secretion throughout the whole experiments, while DED rats showed a dramatic reduction on day 14. DED rats demonstrated ultrastructural damage of Golgi apparatus and endoplasmic reticulum in corneal epithelial cells. Occludin and MUC5AC expressions were significantly downregulated in corneal tissue of DED rats compared with those of normal rats (P < 0.05). Percentage of occludin-MUC5AC-colocalized corneal epithelial cells in DED rats was significantly less compared with those in normal rats (P < 0.01). CONCLUSIONS: Tear film stability was damaged in scopolamine-induced DED rats because of the weakened colocalization between occludin and MUC5AC molecule. This study would provide a potential clue for the pathogenesis and a promising theoretical basis for clinical work of DED.

Evaluating Feasibility of Human Tissue Engineered Respiratory Epithelium Construct as a Potential Model for Tracheal Mucosal Reconstruction.

The normal function of the airway epithelium is vital for the host's well-being. Conditions that might compromise the structure and functionality of the airway epithelium include congenital tracheal anomalies, infection, trauma and post-intubation injuries. Recently, the onset of COVID-19 and its complications in managing respiratory failure further intensified the need for tracheal tissue replacement. Thus far, plenty of naturally derived, synthetic or allogeneic materials have been studied for their applicability in tracheal tissue replacement. However, a reliable tracheal replacement material is missing. Therefore, this study used a tissue engineering approach for constructing tracheal tissue. Human respiratory epithelial cells (RECs) were isolated from nasal turbinate, and the cells were incorporated into a calcium chloride-polymerized human blood plasma to form a human tissue respiratory epithelial construct (HTREC). The quality of HTREC in vitro, focusing on the cellular proliferation, differentiation and distribution of the RECs, was examined using histological, gene expression and immunocytochemical analysis. Histological analysis showed a homogenous distribution of RECs within the HTREC, with increased proliferation of the residing RECs within 4 days of investigation. Gene expression analysis revealed a significant increase (p < 0.05) in gene expression level of proliferative and respiratory epithelial-specific markers Ki67 and MUC5B, respectively, within 4 days of investigation. Immunohistochemical analysis also confirmed the expression of Ki67 and MUC5AC markers in residing RECs within the HTREC. The findings show that calcium chloride-polymerized human blood plasma is a suitable material, which supports viability, proliferation and mucin secreting phenotype of RECs, and this suggests that HTREC can be a potential candidate for respiratory epithelial tissue reconstruction.

Molecular Alterations in Gastric Preneoplastic Lesions and Early Gastric Cancer.

Prognosis of gastric cancer is dramatically improved by early diagnosis. Correa's cascade correlates the expression of some molecular markers with the progression of preneoplastic lesions toward carcinoma. This article reviews the diagnostic and prognostic values of molecular markers in complete (MUC2) and incomplete (MUC2, MUC5AC, and MUC6) intestinal metaplasia, gastric dysplasia/intra-epithelial neoplasia, and early gastric cancer. In particular, considering preinvasive neoplasia and early gastric cancer, some studies have demonstrated a correlation between molecular alterations and prognosis, for example, mucins phenotype in gastric dysplasia, and GATA6, TP53 mutation/LOH and MUC6 in early gastric cancer. Moreover, this review considers novelties from the literature regarding the (immuno)histochemical characterization of diffuse-type/signet ring cell gastric cancer, with particular attention to clinical outcomes of patients. The aim of this review is the evaluation of the state of the art regarding suitable biomarkers used in the pre-surgical phase, which can distinguish patients with different prognoses and help decide the best therapeutic strategy.

Airway mucin MUC5AC and MUC5B concentrations and the initiation and progression of chronic obstructive pulmonary disease: an analysis of the SPIROMICS cohort.

BACKGROUND: We previously described the contributions of increased total airway mucin concentrations to the pathogenesis and diagnosis of the chronic bronchitic component of chronic obstructive pulmonary disease (COPD). Here, we investigated the relative contribution of each of the major airway gel-forming mucins, MUC5AC and MUC5B, to the initiation, progression, and early diagnosis of airways disease in COPD. METHODS: SPIROMICS was a multicentre, observational study in patients aged 40-80 years recruited from six clinical sites and additional subsites in the USA. In this analysis, MUC5AC and MUC5B were quantitated by stable isotope-labelled mass spectrometry in induced sputum samples from healthy never-smokers, ever-smokers at risk for COPD, and ever-smokers with COPD. Participants were extensively characterised using results from questionnaires, such as the COPD assessment test (CAT) and St George's Respiratory Questionnaire; quantitative CT, such as residual volume/total lung capacity ratio (RV/TLC) and parametric response mapping-functional small airway disease (PRM-fSAD); and pulmonary function tests, such as FEV1, forced vital capacity (FVC), and forced expiratory flow, midexpiratory phase (FEF25-75%). Absolute concentrations of both MUC5AC and MUC5B were related to cross-sectional (baseline, initial visit) and 3-year follow-up longitudinal data, including lung function, small airways obstruction, prospective acute exacerbations, and smoking status as primary outcomes. This study is registered with ClinicalTrials.gov (NCT01969344). FINDINGS: This analysis included 331 participants (mean age 63 years [SEM 9·40]), of whom 40 were healthy never-smokers, 90 were at-risk ever-smokers, and 201 were ever-smokers with COPD. Increased MUC5AC concentrations were more reliably associated with manifestations of COPD than were MUC5B concentrations, including decreased FEV1 and FEF25-75%, and increased prospective exacerbation frequency, RV/TLC, PRM-fSAD, and COPD assessment scores. MUC5AC concentrations were more reactive to cigarette smoke exposure than were MUC5B concentrations. Longitudinal data from 3-year follow-up visits generated a multivariate-adjusted odds ratio for two or more exacerbations of 1·24 (95% CI 1·04-1·47, p=0·015) for individuals with high baseline MUC5AC concentration. Increased MUC5AC, but not MUC5B, concentration at baseline was a significant predictor of FEV1, FEV1/FVC, FEF25-75%, and CAT score decline during the 3-year follow-up. Moreover, current smokers in the at-risk group showed raised MUC5AC concentrations at initial visits and decreased lung function over 3 years. By contrast, former smokers in the at-risk group showed normal MUC5AC concentrations at the initial visit and preserved lung function over 3 years. INTERPRETATION: These data indicate that increased MUC5AC concentration in the airways might contribute to COPD initiation, progression, exacerbation risk, and overall pathogenesis. Compared with MUC5B, greater relative changes in MUC5AC concentrations were observed as a function of COPD severity, and MUC5AC concentration seems to be an objective biomarker to detect disease in at-risk and pre-COPD individuals. These data suggest that MUC5AC-producing pathways could be potential targets for future therapeutic strategies. Thus, MUC5AC could be a novel biomarker for COPD prognosis and for testing the efficacy of therapeutic agents. FUNDING: National Institutes of Health; National Heart, Lung, and Blood Institute.

Simple mucinous cyst: another potential cancer precursor in the pancreas? Case report with molecular characterization and systematic review of the literature.

Cystic lesions of the pancreas may range from benign to precursors of pancreatic cancer. Simple mucinous cyst (SMC) is larger than 1 cm, has a gastric-type flat mucinous lining, and minimal atypia without ovarian-type stroma. We report a new case of pancreatic SMC, coupling a systematic review of the English literature mainly focused on their clinic-pathological features. We reviewed 103 cases of SMC in adults (73 women), averaging 57 (range, 26-70) years. The SMCs were located in the body-tail region of the pancreas in 60 (58%) cases, presenting as single cystic lesions in 94% of cases; 43% of patients were asymptomatic. A preoperative fine-needle aspiration of the cyst fluid detected amylase and carcinoembryonic antigen positivity in 71% and 76% of cases, respectively. Patients underwent surgery mostly for suspected malignancy; in 83% of cases, a standard pancreatic resection was performed. Mean SMC size was 4.9 (range, 1.5-12.0) cm. Mucins MUC5AC and MUC6 resulted positive in 77% and 81% of cases performed, respectively, whereas MUC2 was negative in all but one patient. The SMC from our institution was characterized by a KRAS somatic mutation. The diagnosis of SMC should be considered when a solitary pancreatic cyst larger than 1 cm is detected in asymptomatic patients. To establish a correct diagnosis, an extensive histologic/immunohistochemical analysis is essential. The presence of a KRAS mutation highlights that SMC may represent another potential pancreatic cancer precursor.

Porphyromonas gingivalis gingipains potentially affect MUC5AC gene expression and protein levels in respiratory epithelial cells.

Porphyromonas gingivalis (Pg) is a periodontopathic pathogen that may affect MUC5AC-related mucus hypersecretion along airway epithelial cells. Here, we attempted to establish whether Pg virulence factors (lipopolysaccharide, FimA fimbriae, gingipains) affect MUC5AC in immortalized and primary bronchial cells. We report that MUC5AC gene expression and protein levels are affected by Pg culture supernatant, but not by lipopolysaccharide or FimA fimbriae. Cells treated with either Pg single (Kgp or Rgp) or double (Kgp/Rgp) mutants had altered levels of MUC5AC gene expression and protein levels, and MUC5AC staining of double mutant-treated mouse lung cells showed that MUC5AC protein levels were unaffected. Taken together, we propose that Pg gingipains may be the primary virulence factor that influences both MUC5AC gene expression and protein levels.

Intracholecystic tubular non-mucinous neoplasm (ICTN) of the gallbladder: a clinicopathologically distinct, invasion-resistant entity.

Preinvasive tumor-forming gallbladder neoplasms that are composed of small, non-mucinous tubules with complex architecture remain a poorly characterized group. Here, we evaluated the clinicopathological characteristics of this entity. Twenty-eight examples were analyzed. Tumors were invariably pedunculated polyps with thin stalks, often presented as loosely attached intraluminal nodules, with cauliflower architecture (akin to cholesterol polyps) comprised of compact, back-to-back acinar-like, small tubular units with minimal/no cytoplasm showing variable complexity, creating a picture distinct from the other tubular type dysplasia in the gallbladder. Their limited stroma showed distinctive amorphous amyloid-like hyalinization (39%). While some had round nuclei with single prominent nucleoli, others exhibited slightly more elongated nuclei with washed out chromatin reminiscent of papillary thyroid carcinoma. Squamoid/meningothelial-like morules (71%) and subtle neuroendocrine cell clusters (39%) were frequent. The level of cytoarchitectural atypia qualified as high-grade dysplasia (HGD) in all cases, but none were invasive. The background mucosa showed no dysplasia, but cholesterolosis. The majority (n = 8/12) showed diffuse MUC6 expression and lacked MUC5AC expression. Based on these observations, 635 gallbladder carcinomas were re-analyzed for residual/adjacent lesions with entity-defining characteristics disclosed here, and none could be identified. Preinvasive tubular non-mucinous neoplasm of the gallbladder, which we propose to classify as intracholecystic tubular non-mucinous neoplasm, is a clinicopathologically discrete entity, which tends to occur in uninjured gallbladders and in association with cholesterol polyps. By being tubular, non-mucinous and MUC6-positive, it is akin to intraductal tubulopapillary neoplasms of pancreatobiliary tract, but it is also different in many other aspects. Although their cytoarchitectural complexity warrants an HGD/carcinoma classification, they do not show invasion and their distinct characteristics warrant their separate classification.

A combination of cytokeratin 5/6, p63, p40 and MUC5AC are useful for distinguishing squamous cell carcinoma from adenocarcinoma of the cervix.

PURPOSE: Squamous cell carcinomas and adenocarcinomas are the most common types of cervical cancer. Compared to squamous cell carcinomas, adenocarcinomas are more common in younger women and have a poorer prognosis. Yet, so far, no useful biomarkers have been developed for these two types of cancer. In the following study, we examined the combination of cytokeratin 5/6, p63, p40 and MUC5AC for distinguishing squamous cell carcinoma (SCC) from adenocarcinoma of the cervix (AEC). MATERIALS AND METHODS: A total of 101 SCC and 108 AEC were collected. Immunohistochemical analyses were conducted to determine the expression of CK5/6, p63, p40, CK7 and MUC5AC. One pathologist who was blinded to the patient's clinical and pathological data interpreted the staining results. RESULTS: MUC5AC and CK7 were detected in 81.48 and 82.41% of AEC cases compared to 9.9 and 49.50% of SCC cases (P < 0.05); the specificity of MUC5AC was higher than that of CK7 in AEC (P < 0.05). The sensitivity of MUC5AC combined with p40 or p63 was similar to that of CK7, but the specificity was slightly higher than that of CK7 in AEC. Moreover, the expression of MUC5AC was correlated with the degree of tumor differentiation in adenocarcinomas (P = 0.036) and was not related to the prognosis of cervical adenocarcinoma and subtypes. CONCLUSIONS: MUC5AC may be useful as a biomarker for differential diagnoses between squamous carcinoma and adenocarcinoma of the cervix.

Altered mucins and aquaporins indicate dry eye outcome in patients undergoing Vitreo-retinal surgery.

Vitreo-retinal (VR) surgeries induce conjunctival changes. However, there are no study reports regarding prevalence and severity of dry eye after these surgeries. This study evaluated dry eye outcome after VR surgery. Patients undergoing VR surgery classified as scleral buckle and microincision vitrectomy surgery (n = 44, mean age: 56.09±10.2 years) were recruited. Dry eye evaluation was done before and 8 weeks after surgery (2 weeks after omitting topical eye drops). Conjunctival imprint cytology for goblet cell count and tear Mucin 5AC (MUC5AC) protein estimation was done. Gene expressions of MUC5AC, MUC4, MUC16, Aquaporin 4 (AQP4) and AQP5 were analyzed in the conjunctival imprint cells by qPCR. None of the patients exhibited clinical signs of dry eye after VR surgery. But the conjunctival goblet cell density (GCD) was significantly lowered post-VR surgery (63% cases, **p = 0.012) with no alterations in the tear MUC5AC protein. Post-VR surgery, the conjunctival cell gene expression of MUC4, MUC16 and AQP4 were significantly increased (*p = 0.025, *p = 0.05 and *p = 0.02 respectively) and AQP5 was significantly lowered (*p = 0.037), with no change in MUC5AC expression. Tear cytokines were significantly increased post-VR surgery (anti-inflammatory: IL1RA, IL4, IL5, IL9, FGF; PDGFbb and pro-inflammatory: IL2, IL6, IL15, GMCSF and IFNg). Though clinical signs of dry eye were not observed after VR surgery, ocular surface changes in the form of reduced GCD, altered MUC5AC, MUC4, MUC16, AQP4, AQP5 and cytokines are suggestive of dry eye outcome at the molecular level especially inpatients aged above 51 years, especially female gender and those who are diabetic.

MUC5AC enhances tumor heterogeneity in lung adenocarcinoma with mucin production and is associated with poor prognosis.

OBJECTIVE: The clinicopathological significance of Mucin5AC (MUC5AC) in lung adenocarcinoma with mucin production is still unclear. This study aimed to explore MUC5AC expression in lung adenocarcinoma with mucin production and its correlation with histological subtypes, common driver mutations and its impact on prognosis. METHODS: MUC5AC and thyroid transcription factor 1 immunohistochemistry was performed on surgical samples from 90 patients with lung adenocarcinoma with mucin production. Common driver mutations including EGFR and KRAS mutations and ALK rearrangement were detected by established methods. RESULTS: MUC5AC was significantly associated with lymphovascular invasion (P = 0.023) and tumors with intra-cytoplasmic mucin (P < 0.001). Moreover, MUC5AC was more significant in invasive mucinous adenocarcinoma (P < 0.001), as well as in tumors with KRAS mutations (P = 0.005) and a lack of thyroid transcription factor 1 expression (P < 0.001). Conversely, MUC5AC was less significantly detected in acinar predominant adenocarcinoma (P = 0.036) and tumors with EGFR mutations (P = 0.001). Notably, MUC5AC in non-pure mucinous subtype of lung adenocarcinoma with mucin production showed more aggressive behavior, distinct expression pattern and a lack of significant correlation with thyroid transcription factor 1 (P = 0.113) when compared with pure mucinous subtype. MUC5AC-positive tumors were significantly associated with a worse prognosis compared to MUC5AC-negative tumors (P < 0.001). A multivariate survival analysis showed that MUC5AC was an independent prognosis factor for poor prognosis (P = 0.006). CONCLUSIONS: The clinicopathological features of non-pure mucinous subtype of lung adenocarcinoma with mucin production were distinct and should be distinguished from pure mucinous subtype. MUC5AC was associated with poor prognosis and could be a potential therapeutic target for this distinct type of lung adenocarcinoma that has few effective treatments.

Mutational profiling and immunohistochemical analysis of a surgical series of ampullary carcinomas.

AIMS: Knowledge regarding the genetic features of ampullary carcinoma (AC) in European patients is limited. The utility of tumour markers for the establishment of a malignant diagnosis in biopsies from the ampullary region has not been fully elucidated. We aimed to describe the clinical, pathological, immunohistochemical (IHC) and genetic features of a Danish series of surgically resected ACs. METHODS: Surgically resected ACs (n=59) were examined regarding (1) clinicopathological features, (2) histological subtypes, (3) expression of IMP3, maspin, MUC5AC and S100P and (4) next-generation sequencing using a hybrid capture-based platform (Illumina HiSeq2500), including 315 cancer-related genes plus introns from 28 genes often rearranged or altered in cancer. Tumour mutational burden (TMB) and microsatellite instability (MSI) were also evaluated. RESULTS: Pancreatobiliary adenocarcinomas (PB-AC), intestinal adenocarcinomas (INT-AC), other ampullary tumours and mixed adenocarcinomas represented 45.8%, 23.7%, 16.9% and 13.6%. The proportion of IHC-positive ACs (score ≥2) was: Maspin (94.9%), IMP3 (67.8%), S100P (39.0%) and MUC5AC (18.6%). Most frequently altered genes were TP53 (59.3%), KRAS (40.7%), APC (27.8%), SMAD4 (20.4%), CDKN2A (16.7%) and ARID2/PIK3CA (each 11.1%). MUC5AC and S100P were frequently expressed in PB-AC, APC alterations frequent in INT-AC, SOX9 alterations were exclusive in INT-AC and MDM2 and FRS2 alterations in PB-AC. Four of 49 ACs (8.2%) were TMB-high/MSI-high and showed loss of MLH1 and PMS2. CONCLUSIONS: PB-AC was the most frequent histological subtype of AC. Maspin and IMP3 were the IHC tumour markers with the highest sensitivity. Adenocarcinoma subtypes differed regarding several genetic alterations, whose predictive value remains to be evaluated.

Muc5b is mainly expressed and sialylated in the nasal olfactory epithelium whereas Muc5ac is exclusively expressed and fucosylated in the nasal respiratory epithelium.

The nose is a complex organ that filters and warms breathing airflow. The nasal epithelium is the first barrier between the host and the external environment and is covered by a mucus gel that is poorly documented. Mucins are large, heavily O-glycosylated polymeric molecules secreted in the nose lumen by specialized cells, and they are responsible for the biochemical properties of the mucus gel. The mucus traps particles and clears them, and it also bathes microbiota, host molecules, and receptors that are all essential for odor perception in the olfactory epithelium. We used histology and immunohistochemistry to study the expression of the two main airway polymeric mucins, Muc5ac and Muc5b, in wild-type, green fluorescent protein-reporter Muc5b, and in genetically Muc5b-deficient mice. We report that Muc5ac is produced by goblet cells at the cell surface in the respiratory epithelium but is not expressed in the olfactory epithelium, whereas Muc5b is secreted by Bowman's glands situated in the lamina propria beneath the olfactory epithelium and also by goblet cells in the distal part of the respiratory epithelium. We also observed that Muc5b-deficient mice exhibited depletion of Bowman's glands. Using lectins, we found that terminally O-glycosylated chains of Muc5b were sialylated but not fucosylated, whereas Muc5ac was fucosylated but not sialylated. Specific localization and specific terminal glycosylation of the two mucins suggest different functions of the mucins.

Modulation of intestinal epithelial permeability and mucin mRNA (MUC2, MUC5AC, and MUC5B) expression and protein secretion in Caco-2/HT29-MTX co-cultures exposed to aflatoxin M1, ochratoxin A, and zearalenone individually or collectively.

Aflatoxin M1 (AFM1), ochratoxin A (OTA), and zearalenone (ZEA) are mycotoxins commonly found in milk. Mycotoxin contamination has caused food safety concerns worldwide since most of the toxic effects in humans are serious. The combined toxic effects of these mycotoxins on intestinal epithelial cells have not been reported. Herein, we investigated the combined effects of AFM1, OTA, and ZEA on intestinal integrity and define the underlying mechanisms(s) of their effects in Caco-2/HT29-MTX co-cultures. Our results showed that the mixtures of AFM1 + OTA, AFM1 + ZEA, and AFM1 + ZEA + OTA significantly increased epithelial permeability. Immunofluorescence analysis and transmission electron microscopy revealed that mycotoxins altered TJ proteins morphology and disrupted their structures. Also, the present study showed that mixtures of mycotoxins significantly modulated MUC5AC and MUC5B mRNA levels and protein secretion. This study demonstrated that the effects of mixtures of mycotoxins on intestinal barrier function were more significant than AFM1 alone. More importantly, the damage of intestinal integrity caused by mycotoxins was correlated to the change of the TJ proteins location and the decrease of mucin secretion. Mixtures of AFM1, OTA, and ZEA in food might pose a health risk to consumers, particularly in children, and toxin risks should be considered.

Localization of Secretory Mucins MUC5AC and MUC5B in Normal/Healthy Human Airways.

RATIONALE: MUC5AC and MUC5B are the predominant gel-forming mucins in the mucus layer of human airways. Each mucin has distinct functions and site-specific expression. However, the regional distribution of expression and cell types that secrete each mucin in normal/healthy human airways are not fully understood. OBJECTIVES: To characterize the regional distribution of MUC5B and MUC5AC in normal/healthy human airways and assess which cell types produce these mucins, referenced to the club cell secretory protein (CCSP). METHODS: Multiple airway regions from 16 nonsmoker lungs without a history of lung disease were studied. MUC5AC, MUC5B, and CCSP expression/colocalization were assessed by RNA in situ hybridization and immunohistochemistry in five lungs with histologically healthy airways. Droplet digital PCR and cell cultures were performed for absolute quantification of MUC5AC/5B ratios and protein secretion, respectively. MEASUREMENTS AND MAIN RESULTS: Submucosal glands expressed MUC5B, but not MUC5AC. However, MUC5B was also extensively expressed in superficial epithelia throughout the airways except for the terminal bronchioles. Morphometric calculations revealed that the distal airway superficial epithelium was the predominant site for MUC5B expression, whereas MUC5AC expression was concentrated in proximal, cartilaginous airways. RNA in situ hybridization revealed MUC5AC and MUC5B were colocalized with CCSP-positive secretory cells in proximal superficial epithelia, whereas MUC5B and CCSP-copositive cells dominated distal regions. CONCLUSIONS: In normal/healthy human airways, MUC5B is the dominant secretory mucin in the superficial epithelium and glands, with distal airways being a major site of expression. MUC5B and MUC5AC expression is a property of CCSP-positive secretory cells in superficial airway epithelia.

"Extramammary-Type" Paget Disease of the Breast.

BACKGROUND: Mammary Paget disease and extramammary Paget disease (EMPD) have different prognoses. Because they are indistinguishable on histopathological grounds, they must be distinguished on a topographical basis. OBJECTIVE: To study cases of Paget disease of the breast, which show similarities to EMPD. METHODS: Cases were selected by 2 different approaches: (1) those with an exceptionally good evolution and no evidence of subjacent tumor and (2) those expressing MUC5AC. RESULTS: Five cases were collected. All cases showed an indolent behavior with a known long clinical history in 2 cases (9 and 25 years, respectively) and a long follow-up in all cases but one (4-8 years). In all cases but one, surgery was performed, and no parenchymal tumor was found (either intraductal or infiltrating). All cases expressed cytokeratin 7 and MUC5AC without expression of MUC2, S100, or p40. LIMITATIONS: The short number of cases is a limitation of this study. In addition, case 5 is recent, so we have a very short follow-up. CONCLUSIONS: Some cases of mammary Paget disease behave like EMPD with slow progression and with no underlying associated tumor. Immunoexpression of MUC5AC might be a clue to identify them.

Expression of Gastric Markers Is Associated with Malignant Potential of Nonampullary Duodenal Adenocarcinoma.

BACKGROUND: Sporadic nonampullary duodenal epithelial tumors (NADETs) are uncommon, and thus their clinicopathological features have not been fully assessed. AIMS: In this study, we have analyzed a series of early sporadic NADETs, focusing on various immunohistological features. METHODS: We conducted a multicenter retrospective analysis of 68 patients with endoscopically resected sporadic NADETs. Associations between immunohistological features and clinicopathological features were statistically analyzed. RESULTS: The 68 patients consisted of 46 men (68%) and 22 women (32%) with a mean age of 60.7 ± 12.2 years (range 37-85 years). The 68 tumors were composed of 39 adenomas (57%) and 29 early-stage adenocarcinomas (43%). Duodenal adenocarcinomas were larger in size than adenomas and had papillary architecture in their pathological diagnosis with statistical significance. Duodenal adenocarcinomas also demonstrated a significantly higher expression of gastric markers (MUC5AC and MUC6) and a higher MIB-1 index. Duodenal adenomas were contrastively apt to express intestinal markers (MUC2, CDX1 and CDX2). Of the 68 cases analyzed, there were only 3 tumors positive for p53 staining, all of which were adenocarcinoma. When 7 submucosal invasive cancers and 21 intramucosal cancers were compared, submucosal invasion was positively associated with expression of MUC5AC. Also, submucosal invasion showed strong association with double-positivity of MUC5AC and MUC6. CONCLUSIONS: Our results indicate that immunohistochemical evaluation is useful for predicting malignant potential of NADETs, especially focusing on the expression of gastrointestinal markers.

MUC5AC Levels Associated With Respiratory Syncytial Virus Disease Severity.

To assess MUC5AC as a biomarker for respiratory syncytial virus (RSV) disease severity, we tested nasal aspirates from RSV+ children with mild, moderate, and severe disease. Levels were significantly higher in those in the severe and moderate groups compared to mild group, indicating MUC5AC may be a useful biomarker for RSV disease severity.

Effects of the Helicobacter pylori Virulence Factor CagA and Ammonium Ion on Mucins in AGS Cells.

PURPOSE: To investigate the effects of Helicobacter pylori (H. pylori)-CagA and the urease metabolite NH4⁺ on mucin expression in AGS cells. MATERIALS AND METHODS: AGS cells were transfected with CagA and/or treated with different concentrations of NH4CL. Mucin gene and protein expression was assessed by qPCR and immunofluorescence assays, respectively. RESULTS: CagA significantly upregulated MUC5AC, MUC2, and MUC5B expression in AGS cells, but did not affect E-cadherin and MUC6 expression. MUC5AC, MUC6, and MUC2 expression in AGS cells increased with increasing NH4⁺ concentrations until reaching a peak level at 15 mM. MUC5B mRNA expression in AGS cells (NH4⁺ concentration of 15 mM) was significantly higher than that at 0, 5, and 10 mM NH4⁺. No changes in E-cadherin expression in AGS cells treated with NH4⁺ were noted, except at 20 mM. The expression of MUC5AC, MUC2, and MUC6 mRNA in CagA-transfected AGS cells at an NH4⁺ concentration of 15 mM was significantly higher than that at 0 mM, and decreased at higher concentrations. The expression of MUC5B mRNA increased with increases in NH4⁺ concentration, and was significantly higher compared to that in untreated cells. No significant change in the expression of E-cadherin mRNA in CagA-transfected AGS cells was observed. Immunofluorescence assays confirmed the observed changes. CONCLUSION: H. pylori may affect the expression of MUC5AC, MUC2, MUC5B, and MUC6 in AGS cells via CagA and/or NH4⁺, but not E-cadherin.