The expression of MUC4 and MUC5AC is related to the biologic malignancy of intraductal papillary mucinous neoplasms of the pancreas

Extracellular Vesicle Analysis Allows for Identification of Invasive IPMN

BACKGROUND AND AIMS

Advances in cross-sectional imaging have resulted in increased detection of intraductal papillary mucinous neoplasms (IPMNs), and their management remains controversial. At present, there is no reliable noninvasive method to distinguish between indolent and high risk IPMNs. We performed extracellular vesicle (EV) analysis to identify markers of malignancy in an attempt to better stratify these lesions.

METHODS

Using a novel ultrasensitive digital extracellular vesicle screening technique (DEST), we measured putative biomarkers of malignancy (MUC1, MUC2, MUC4, MUC5AC, MUC6, Das-1, STMN1, TSP1, TSP2, EGFR, EpCAM, GPC1, WNT-2, EphA2, S100A4, PSCA, MUC13, ZEB1, PLEC1, HOOK1, PTPN6, and FBN1) in EV from patient-derived cell lines and then on circulating EV obtained from peripheral blood drawn from patients with IPMNs. We enrolled a total of 133 patients in two separate cohorts: a clinical discovery cohort (n = 86) and a validation cohort (n = 47).

RESULTS

From 16 validated EV proteins in plasma samples collected from the discovery cohort, only MUC5AC showed significantly higher levels in high-grade lesions. Of the 11 patients with invasive IPMN (inv/HG), 9 had high MUC5AC expression in plasma EV of the 11 patients with high-grade dysplasia alone, only 1 had high MUC5AC expression (sensitivity of 82%, specificity of 100%). These findings were corroborated in a separate validation cohort. The addition of MUC5AC as a biomarker to imaging and high-riskstigmata allowed detection of all cases requiring surgery, whereas imaging and high-risk stigmata alone would have missed 5 of 14 cases (36%).

CONCLUSIONS

MUC5AC in circulating EV can predict the presence of invasive carcinoma within IPMN. This approach has the potential to improve the management and follow-up of patients with IPMN including avoiding unnecessary surgery.

Expression of CD117, CK17, CK20, MUC4, villin and mismatch repair deficiency in pancreatic intraductal papillary mucinous neoplasm

Among pancreatic intraductal papillary neoplasms, gastric, intestinal, and pancreatobiliary intraductal papillary mucinous neoplasm (IPMN), intraductal oncocytic papillary neoplasm (IOPN), and intraductal tubulopapillary neoplasm (ITPN) have been defined, differing regarding association with invasive carcinoma and prognosis. Immunohistochemistry (IHC) can help in the distinction of these neoplasms, but a proportion is unclassifiable using recommended markers. Hence, additional markers useful for the typing of pancreatic intraductal papillary neoplasms are needed. The reported frequencies of the different types of IPMNs in surgical series vary to some extent, and such data based on Danish patients are currently lacking. Besides, the role of mismatch repair (MMR) deficiency in these neoplasms has not been fully elucidated. We aimed to evaluate the frequency of different types of pancreatic intraductal papillary neoplasms in a Danish cohort. Furthermore, we aimed to examine the utility of CD117, CK17, CK20, MUC4, and villin as markers for their distinction, in addition to the recommended markers MUC1, MUC2, MUC5AC, MUC6 and CDX2, and to evaluate the frequency of MMR deficiency. We typed 40 consecutively resected pancreatic intraductal papillary neoplasms according to the WHO criteria from 2019. IHC for CD117, CDX2, CK17, CK20, MLH1, MSH2, MSH6, MUC1 (H23), MUC1 (Ma695), MUC2, MUC4, MUC5AC, MUC6, PMS2, and villin was performed and evaluated using a five-tiered semiquantitative scale. A subset of the tumours was examined with PCR for microsatellite instability (MSI). Most tumours were intestinal (40 %) and gastric (40 %) IPMNs, followed by pancreatobiliary (17 %) IPMNs and IOPN (3 %). All cases were MMR proficient. We found a higher expression of MUC4, CK20 and villin in intestinal compared to gastric IPMNs (p < 0.01, p < 0.001 and p < 0.001). MUC4 was more strongly expressed in intestinal compared to pancreatobiliary IPMNs, while the opposite was found for CK17 (p < 0.05 and p < 0.05). IOPN showed strong CD117 expression (score 4), while all gastric IPMNs were negative and 50 % and 29 % of intestinal and pancreatobiliary IPMNs only showed weak expression (score 1). Our data suggest that CK20, MUC4 and villin may aid in the identification of intestinal IPMNs, while CK17 and CD117 may aid in the identification of pancreatobiliary IPMNs and IOPN, in some cases. However, additional studies evaluating these markers in pancreatic intraductal papillary neoplasms are needed.

Molecular Diagnosis of Cystic Neoplasms of the Pancreas: a Review

BACKGROUND

The prevalence of incidental pancreatic cystic neoplasms (PCNs) has increased dramatically with advancements in cross-sectional imaging. Diagnostic imaging is limited in differentiating between benign and malignant PCNs. The aim of this review is to provide an overview of biomarkers that can be used to distinguish PCNs.

METHODS

A review of the literature on molecular diagnosis of cystic neoplasms of the pancreas was performed.

RESULTS

Pancreatic cysts can be categorized into inflammatory and non-inflammatory lesions. Inflammatory cysts include pancreatic pseudocysts. Noninflammatory lesions include both mucinous and non-mucinous lesions. Mucinous lesions include intraductal papillary mucinous neoplasm (IPMN) and mucinous cystic neoplasm. Non-mucinous lesions include serous cystadenoma and solid-pseudopapillary tumor of the pancreas. Imaging, cyst aspiration, and histologic findings, as well as carcinoembryonic antigen and amylase are commonly used to distinguish between cyst types. However, molecular techniques to detect differences in genetic mutations, protein expression, glycoproteomics, and metabolomic profiling are important developments in distinguishing between cyst types.

DISCUSSION

Nomograms incorporating common clinical, laboratory, and imaging findings have been developed in a better effort to predict malignant IPMN. The incorporation of top molecular biomarker candidates to nomograms may improve the predictive ability of current models to more accurately diagnose malignant PCNs.

Cyst Fluid Biosignature to Predict Intraductal Papillary Mucinous Neoplasms of the Pancreas with High Malignant Potential

BACKGROUND

Current standard-of-care technologies, such as imaging and cyst fluid analysis, are unable to consistently distinguish intraductal papillary mucinous neoplasms (IPMNs) of the pancreas at high risk of pancreatic cancer from low-risk IPMNs. The objective was to create a single-platform assay to identify IPMNs that are at high risk for malignant progression.

STUDY DESIGN

Building on the Verona International Consensus Conference branch duct IPMN biomarker review, additional protein, cytokine, mucin, DNA, and microRNA cyst fluid targets were identified for creation of a quantitative polymerase chain reaction-based assay. This included messenger RNA markers: ERBB2, GNAS, interleukin 1β, KRAS, MUCs1, 2, 4, 5AC, 7, prostaglandin E2R, PTGER2, prostaglandin E synthase 2, prostaglandin E synthase 1, TP63; microRNA targets: miRs 101, 106b, 10a, 142, 155, 17, 18a, 21, 217, 24, 30a, 342, 532, 92a, and 99b; and GNAS and KRAS mutational analysis. A multi-institutional international collaborative contributed IPMN cyst fluid samples to validate this platform. Cyst fluid gene expression levels were normalized, z-transformed, and used in classification and regression analysis by a support vector machine training algorithm.

RESULTS

From cyst fluids of 59 IPMN patients, principal component analysis confirmed no institutional bias/clustering. Lasso (least absolute shrinkage and selection operator)-penalized logistic regression with binary classification and 5-fold cross-validation used area under the curve as the evaluation criterion to create the optimal signature to discriminate IPMNs as low risk (low/moderate dysplasia) or high risk (high-grade dysplasia/invasive cancer). The most predictive signature was achieved with interleukin 1β, MUC4, and prostaglandin E synthase 2 to accurately discriminate high-risk cysts from low-risk cysts with an area under the curve of up to 0.86 (p = 0.002).

CONCLUSIONS

We have identified a single-platform polymerase chain reaction-based assay of cyst fluid to accurately predict IPMNs with high malignant potential for additional studies.

Intraductal tubulopapillary neoplasm (ITPN) of the pancreas associated with an invasive component: a case report with review of the literature

BACKGROUND

Intraductal tubulopapillary neoplasm (ITPN) depicts a distinct entity in the subgroup of premalignant epithelial tumors of the pancreas. Although the histomorphological and immunophenotypical characterization of ITPN has been described by several authors in terms of report of case series in the past, the rarity of that tumor subtype and similarity to other entities still makes identification of ITPN a challenge for radiologists and pathologists. To date, little is known about tubulopapillary carcinoma that can evolve from ITPN.

CASE PRESENTATION

In the present work, we analyze one case of ITPN associated with an invasive component and discuss the results involving the current literature. Collected patient data included medical history, clinical symptoms, laboratory tests, radiological imaging, reports of interventions and operation, and histopathological and immunohistochemical examinations. The patient initially presented with acute pancreatitis. A solid tumor obstructing the main pancreatic duct and sticking out of the papilla of Vater was detected and caught via endoscopic intervention. Histopathological examination of the specimen revealed mainly tubular growth pattern with back to back tubular glands. Immunohistochemically, the tumor was strongly positive for keratin 7 (CK7) and pankeratin AE1/AE3, and alpha 1 antichymotrypsin; negative for synaptophysin and chromogranin A, CDx2, CK20, S100, carcinoembryonic antigen (CEA), MUC 2, MUC5AC, and somatostatin; and in part positive for CA19-9. Extended pancreatoduodenectomy was performed, the final diagnosis was tubulopapillary carcinoma grown in an ITPN.

CONCLUSION

The identification of an ITPN of the pancreas can be a challenging task. Endoscopic retrograde cholangiopancreaticography is an excellent tool to directly see and indirectly visualize the intraductal solid tumor and to take a biopsy for histopathological evaluation at the same time. Together with a thorough immunohistochemical workup, differential diagnoses can be ruled out quickly. To date, reports of ITPN are rare and little is known about the potential for malignant transformation and the prognosis of tubulopapillary carcinoma grown from an ITPN. Radical surgical resection following oncologic criteria is recommended; however, more data will be needed to assess an adequate treatment and follow-up standard.

Immunohistochemical Classification of Ampullary Carcinomas: Critical Reappraisal Fails to Confirm Prognostic Relevance for Recently Proposed Panels, and Highlights MUC5AC as a Strong Prognosticator

Recently, immunohistochemistry-based classifications of ampullary carcinomas have been proposed (Ang and colleagues [PMID: 24832159]; Chang and colleagues [PMID: 23439753]). In this study, the prognostic value of Ang/Chang panel markers (CK20, MUC1, MUC2, CDX2) as well as other markers (CK7, MUC5AC, and MUC6) were tested on full-faced sections of 136 ampullary carcinoma resections with substantial (>5 mm) invasion. Immunohistochemistry was correlated with both histologic classification (intestinal [INT], pancreatobiliary [PB], or nontubular based on ≥3/5 observer agreement) and clinical outcome. No prognostic correlation was found with MUC1, CDX2, MUC2 or CK20 despite testing with different quantitative cutoffs. CK7 and CK20 were nonspecific. Ang classification had reasonable correlation with histologic subclassification of tubular cases as INT versus PB with high specificity but low sensitivity and ambiguous category was large (29%) and included also some classical cases. Prognostically, Ang classification approached but did not reach statistical significance, even when their large "ambiguous" group was eliminated and only tubular cases were analyzed (Ang-INT vs. Ang-PB; P=0.08). The Chang panel, in which the definition of the INT subcategory is not clearly defined, only marginally reached prognostic significance when tested as MUC1+/CDX2- versus MUC1-/CDX2+ and only by Wilcoxon test (P=0.0485) but 31% of the cases were "unclassifiable." The only individual marker that was found to have direct and strong correlation with the clinical outcome was MUC5AC (not used in the Ang or Chang panels), with statistically significant survival differences found with various cutoffs tested (for 20% cutoff, 5-y survival, 68% vs. 31%; P=0.0002). In addition, MUC5AC significantly stratified the histologically PB and INT cases (P=0.01 and 0.03, respectively), as well as Ang's ambiguous and Chang's unclassified cases (P=0.006 and 0.007, respectively). In conclusion, the widely used putative lineage markers, MUC1/MUC2/CK7/CK20/CDX2, do not seem to have direct/significant prognostic correlation either individually or in combination of Ang and Chang panels. Ang panel is helpful as an adjunct in determining the cell lineage with a few caveats. MUC5AC proves to be a significant independent prognosticator and should be incorporated into evaluation of ampullary carcinomas.

High mucin 5AC expression predicts adverse postoperative recurrence and survival of patients with clear-cell renal cell carcinoma

BACKGROUND

Mucin 5AC (MUC5AC), as a member of secreted/gel-forming mucin family, was frequently found to be abnormally expressed in inflammation or malignant diseases. However, the clinic pathologic features and prognostic values of MUC5AC in clear-cell renal cell carcinoma (ccRCC) have not been reported up to now.

METHODS

MUC5AC expression was analyzed by immunohistochemistry on tissue microarrays. Kaplan-Meier survival curves, Univariate and Multivariate Cox analysis and newly-established nomogram model were performed to evaluate the prognostic value.

RESULTS

MUC5AC expression was firstly found to be up-regulated in patients with ccRCC, positively associated with tumor size, pN stage, lymphovascular invasion, Fuhrman grade, rahbdoid differentiation, sarcomatoid features, tumor necrosis, ECOG-PS and recurrence. Furthermore, MUC5AC expression might be contributed to risk stratification of ccRCC patients with TNM stage III+IV or Fuhrman grade 3 or 4 for overall survival (OS) and recurrence-free survival (RFS) analysis, and it was demonstrated to be negatively correlated with OS and RFS of ccRCC patients. What's more, MUC5AC was identified as a potential independent adverse prognostic factor; prediction accuracy of MUC5AC-based new nomogram model was drastically improved for OS and RFS of ccRCC patients.

CONCLUSION

MUC5AC is a promising independent adverse prognostic factor for ccRCC patients, it maybe conducive to postoperative risk stratification and guide treatment in the future.

Mucin expression and the pancreas: A systematic review and meta-analysis

AIM

To assess mucin expression in pancreatic premalignant and malignant states, and to establish its role as a prognostic marker.

METHODS

English Medical literature searches were conducted for “mucin” and “pancreas”. Observational studies were included. Meta-analysis was performed by using Comprehensive meta-analysis software. Pooled odds ratios and 95%CIs were calculated.

RESULTS

Out of 949 eligible papers we found 20 according to the inclusion criteria, including 4262 patients, published till May 31, 2016. Mucin expression increased in pancreatic lesions with OR 10.206 (95%CI: 4.781-21.781, P < 0.0001). Measure of heterogeneity was high: Q = 296.973, df (Q) = 55.00, I² = 81.48%. We found a significant increase in the expression of MUC2, MUC4 and MUC5AC, 13.39, 118.43 and 13.91 times respectively, in pancreatic lesion in comparison with normal pancreatic tissue, and decreased expression of MUC5B.

CONCLUSION

Mucin expression may serve as prognostic marker for transformation of intraductal papillary mucinous neoplasms to ductal adenocarcinoma, for aggressiveness of the pancreatic tumor, and as targets for potential therapy.

Clinicopathological features and surgical outcomes of intraductal tubulopapillary neoplasm of the pancreas: a systematic review

BACKGROUND AND AIMS

Intraductal tubulopapillary neoplasms (ITPNs) of the pancreas are rare. The purpose of this study was to collate and analyze published data on ITPNs of the pancreas to determine the clinicopathological features of the tumors and the surgical outcomes of patients.

PATIENTS AND METHODS

We searched MEDLINE and Igakuchuo-Zasshi for the period of 1980 to 2015 for case reports on surgical resection for ITPN of the pancreas. We evaluated the clinicopathological data associated with pancreatic ITPNs, the prognosis for each patient, and surgical outcomes described in the case reports.

RESULTS

We obtained clinicopathological data for 58 patients (33 men and 25 women) with a mean age of 61 years (range, 35-84 years) who had undergone surgical resection for ITPN of the pancreas, including one patient from our clinic. Although ITPNs of the pancreas have different clinicopathological features to intraductal papillary mucinous neoplasms, the treatment strategy for patients with ITPNs is the same as for patients with other cystic neoplasms of the pancreas. The immunohistochemical features of ITPNs included testing positive for cytokeratin 7 and/or cytokeratin 19 and negative for trypsin, MUC2, MUC5AC, and fascin. The overall 1-, 3-, and 5-year survival rates after surgery for the 37 cases with available data were 97.3, 80.7, and 80.7 %, respectively.

CONCLUSION

Surgical treatment is the only curative management option for patients with ITPN of the pancreas. To determine the best management strategy for this tumor and improve accuracy of prognosis for patients, we will continue to collect and analyze epidemiological and pathological data.

Identification of PAM4 (clivatuzumab)-reactive epitope on MUC5AC: a promising biomarker and therapeutic target for pancreatic cancer

PAM4 is a monoclonal antibody showing high specificity for pancreatic ductal adenocarcinoma (PDAC). Humanized PAM4 labeled with ⁹⁰Y in combination with low-dose gemcitabine has shown promising therapeutic activity, and is being evaluated in a phase III clinical trial. Prior efforts have suggested that PAM4 potentially reacts with MUC5AC, a secretory mucin expressed de novo in early pancreatic neoplasia and retained throughout disease progression. In present study, we provide further evidence validating MUC5AC as the PAM4 antigen, and locate PAM4-reactive epitope within the N-terminal cysteine-rich subdomain 2 (Cys2), thus differentiating PAM4 from most anti-MUC5AC antibodies known to-date. Specifically, we show (i) PAM4-antigen and MUC5AC were co-localized in multiple human cancer cell lines, including Capan-1, BxPC-3, and CFPAC-1; (ii) MUC5AC-specific siRNA prominently reduced the expression of both MUC5AC and PAM4-antigen in CFPAC-1 cells; (iii) PAM4 preferentially binds to the void-volume fractions from Sepharose-CL2B chromatography of Capan-1 culture supernatants, which were revealed by Western blot to display the ladder pattern characteristic of oligomeric MUC5AC; and (iv) the N-terminal Cys2 within several recombinant MUC5AC fragments is essential for binding to PAM4. These findings shed light on the mechanism of PAM4-based diagnosis and treatment for pancreatic cancer, and guide further exploration of its clinical utility.

Exploring the role and diversity of mucins in health and disease with special insight into non-communicable diseases

Mucins are major glycoprotein components of the mucus that coats the surfaces of cells lining the respiratory, digestive, gastrointestinal and urogenital tracts. They function to protect epithelial cells from infection, dehydration and physical or chemical injury, as well as to aid the passage of materials through a tract i.e., lubrication. They are also implicated in the pathogenesis of benign and malignant diseases of secretory epithelial cells. In Human there are two types of mucins, membrane-bound and secreted that are originated from mucous producing goblet cells localized in the epithelial cell layer or in mucous producing glands and encoded by MUC gene. Mucins belong to a heterogeneous family of high molecular weight proteins composed of a long peptidic chain with a large number of tandem repeats that form the so-called mucin domain. The molecular weight is generally high, ranging between 0.2 and 10 million Dalton and all mucins contain one or more domains which are highly glycosylated. The size and number of repeats vary between mucins and the genetic polymorphism represents number of repeats (VNTR polymorphisms), which means the size of individual mucins can differ substantially between individuals which can be used as markers. In human it is only MUC1 and MUC7 that have mucin domains with less than 40% serine and threonine which in turn could reduce number of PTS domains. Mucins can be considered as powerful two-edged sword, as its normal function protects from unwanted substances and organisms at an arm's length while, malfunction of mucus may be an important factor in human diseases. In this review we have unearthed the current status of different mucin proteins in understanding its role and function in various non-communicable diseases in human with special reference to its organ specific locations. The findings described in this review may be of direct relevance to the major research area in biomedicine with reference to mucin and mucin associated diseases.

Molecular pathology of intraductal papillary mucinous neoplasms of the pancreas

Since the first description of intraductal papillary mucinous neoplasms (IPMNs) of the pancreas in the eighties, their identification has dramatically increased in the last decades, hand to hand with the improvements in diagnostic imaging and sampling techniques for the study of pancreatic diseases. However, the heterogeneity of IPMNs and their malignant potential make difficult the management of these lesions. The objective of this review is to identify the molecular characteristics of IPMNs in order to recognize potential markers for the discrimination of more aggressive IPMNs requiring surgical resection from benign IPMNs that could be observed. We briefly summarize recent research findings on the genetics and epigenetics of intraductal papillary mucinous neoplasms, identifying some genes, molecular mechanisms and cellular signaling pathways correlated to the pathogenesis of IPMNs and their progression to malignancy. The knowledge of molecular biology of IPMNs has impressively developed over the last few years. A great amount of genes functioning as oncogenes or tumor suppressor genes have been identified, in pancreatic juice or in blood or in the samples from the pancreatic resections, but further researches are required to use these informations for clinical intent, in order to better define the natural history of these diseases and to improve their management.

Specific glycoforms of MUC5AC and endorepellin accurately distinguish mucinous from nonmucinous pancreatic cysts

Specific protein glycoforms may be uniquely informative about the pathological state of a cyst and may serve as accurate biomarkers. Here we tested that hypothesis using antibody-lectin sandwich arrays in broad screens of protein glycoforms and in targeted studies of candidate markers. We profiled 16 different glycoforms of proteins captured by 72 different antibodies in cyst fluid from mucinous and nonmucinous cysts (n = 22), and we then tested a three-marker panel in 22 addition samples and 22 blinded samples. Glycan alterations were not widespread among the proteins and were mainly confined to MUC5AC and endorepellin. Specific glycoforms of these proteins, defined by reactivity with wheat germ agglutinin and a blood group H antibody, were significantly elevated in mucinous cysts, whereas the core protein levels were not significantly elevated. A three-marker panel based on these glycoforms distinguished mucinous from nonmucinous cysts with 93% accuracy (89% sensitivity, 100% specificity) in a prevalidation sample set (n = 44) and with 91% accuracy (87% sensitivity, 100% specificity) in independent, blinded samples (n = 22). Targeted lectin measurements and mass spectrometry analyses indicated that the higher wheat germ agglutinin and blood group H reactivity was due to oligosaccharides terminating in GlcNAc or N-acetyl-lactosamine with occasional α1,2-linked fucose. The results show that MUC5AC and endorepellin glycoforms may be highly specific and sensitive biomarkers for the differentiation of mucinous from nonmucinous pancreatic cysts.

Genetic markers of malignant transformation in intraductal papillary mucinous neoplasm of the pancreas: a meta-analysis

OBJECTIVES

The objective of this study was to determine the relationship between specific genetic alterations and malignant transformation in intraductal papillary mucinous neoplasm (IPMN) of the pancreas.

METHODS

Quantitative meta-analysis was conducted of studies through October 2010 that adhered to the 1996 World Health Organization guidelines for distinguishing adenoma and borderline IPMN versus carcinoma in surgically resected specimens using a random-effects model. We developed a 6-point scoring system to assess study quality.

RESULTS

Thirty-nine studies (1235 IPMN samples) satisfied the inclusion criteria, and we conducted pooled analysis of 8 genetic markers: MUC1, MUC2, MUC5AC, kRas, p53, hTERT (human telomerase reverse transcriptase), cyclooxygenase 2, and Shh (Sonic hedgehog). Markers having the strongest association with malignant IPMN were hTERT (odds ratio [OR], 11.4; 95% confidence interval [CI], 3.5-36.7) and Shh (OR, 6.9; 95% CI, 2.4-20.2), whereas MUC5AC (OR, 1.0; 95% CI, 0.1-13.9) and kRas (OR, 2.0; 95% CI, 1.0-4.3) showed weak association with IPMN histologic progression.

CONCLUSIONS

Expression of hTERT is strongly associated with malignant transformation in IPMN, consistent with up-regulation of hTERT as a key step in progression of IPMN to cancer. Expression of kRas and MUC5AC is common but not strongly associated with IPMN histologic progression. The quality criteria used here may guide future reporting of genetic markers related to malignant transformation of IPMN.

Identification of HLA-A*0201- and A*2402-restricted epitopes of mucin 5AC expressed in advanced pancreatic cancer

OBJECTIVES

Mucin 5AC (MUC5AC) was previously identified as being expressed in most pancreatic ductal adenocarcinomas. We studied the significance of MUC5AC expression for the development of pancreatic ductal adenocarcinoma and the possibility of using MUC5AC as a target for immunotherapy for pancreatic cancer.

METHODS

We immunohistochemicaly tested MUC5AC expression in 134 specimens. To assess the possibility of using the MUC5AC protein to develop an anticancer vaccine, we examined MUC5AC for possible peptide epitopes to elicit cytotoxic T lymphocytes (CTLs).

RESULTS

In immunohistochemical analysis, MUC5AC was absent from all cell types of the normal pancreas but was expressed de novo in 79% of invasive ductal adenocarcinoma. Clinicopathologically, primary tumors with lymph node metastasis had a significantly higher expression of MUC5AC. Next, we successfully established CTL clones stimulated by the MUC5AC-A02-1398 (FLNDAGACV) and MUC5AC-A24-716 (TCQPTCRSL) peptides, which have specific cytotoxicity against the corresponding HLA-A*0201- and A*2402-positive target cells pulsed with the candidate peptide. Each CTL clone also demonstrated its cytotoxic activity toward pancreatic cancer cells endogenously expressing MUC5AC.

CONCLUSIONS

Our results suggest that MUC5AC is a novel tumor-associated antigen that has potential application as a vaccine against pancreatic cancer.

Pancreatic cyst fluid and serum mucin levels predict dysplasia in intraductal papillary mucinous neoplasms of the pancreas

INTRODUCTION

There are no reliable markers of dysplasia in patients with incidentally discovered intraductal papillary mucinous neoplasms of the pancreas (IPMN). IPMN dysplasia may be associated with mucin protein (MUC) expression and histopathologic subtype. We hypothesize that MUC expression in cyst fluid and serum can identify lesions with high risk of malignancy.

METHODS

Cyst fluid and serum were collected from 40 patients during pancreatectomy for IPMN between 2005 and 2009. Samples were grouped into low-risk (low-grade or moderate dysplasia, n = 21) and high-risk groups (high-grade dysplasia or carcinoma, n = 19). Mucin expression (MUC1, MUC2, MUC4, and MUC5AC) was assessed utilizing enzyme-linked immunosorbent assays.

RESULTS

MUC2 and MUC4 cyst fluid concentrations were elevated in high-risk versus low-risk groups (10 ± 3.0 ng/ml vs. 4.4 ± 1.2 ng/ml, p = 0.03; 20.6 ± 10.6 ng/ml vs. 4.5 ± 1.4 ng/ml, p = 0.03, respectively). Corresponding serum samples revealed higher levels of MUC5AC in high-risk compared with low-risk patients (19.9 ± 9.3 ng/ml vs. 2.2 ± 1.1 ng/ml, p = 0.04). Histopathologic subtype was significantly associated with grade of dysplasia, and the intestinal subtype displayed increased MUC2 cyst fluid concentrations (13.8 ± 6.5 ng/ml vs. 4.1 ± 0.9 ng/ml, p = 0.02).

CONCLUSIONS

In this study, high-risk IPMN showed elevated cyst fluid concentrations of MUC2 and MUC4, and increased serum levels of MUC5AC. High-risk IPMN also displayed a distinct mucin expression profile in specific histologic subtypes. These data, if validated, may allow surgeons to more appropriately select patients for operative resection.

Predictive factors associated with malignancy of intraductal papillary mucinous pancreatic neoplasms

AIM

To identify preoperative predictive factors associated with malignancy of intraductal papillary mucinous neoplasms (IPMNs) of the pancreas.

METHODS

Between April 1995 and April 2010, 129 patients underwent surgical resection for IPMNs at our institute and had confirmed pathologic diagnoses. The medical records were retrospectively reviewed and immunohistochemical staining for mucin (MUC) in pancreatic tissues was performed.

RESULTS

Univariate analysis showed that the following five variables were closely associated with malignant IPMNs preoperatively: absence of extrapancreatic malignancy; symptoms; tumor size > 4 cm; main pancreatic duct (MPD) size > 7 mm; and lymph node enlargement on preoperative computed tomography (CT). Multivariate analysis revealed that the following two factors were significantly associated with malignant IPMNs preoperatively: MPD size > 7 mm [odds ratio (OR) = 2.50]; and lymph node enlargement on preoperative CT (OR = 3.57). No significant differences in the expression of MUC1, MUC2 and MUC5AC were observed between benign and malignant IPMNs.

CONCLUSION

MPD size > 7 mm and preoperative lymph node enlargement on CT are useful predictive factors associated with malignancy of IPMNs.

Molecular pathogenesis of intraductal papillary mucinous neoplasms of the pancreas

Over the last 3 decades, there have been substantial improvements in diagnostic imaging and sampling techniques to evaluate pancreatic diseases. The modern technology has helped us to recognize premalignant conditions of pancreas including mucinous cystic neoplasms and intraductal papillary mucinous neoplasms (IPMNs). Differentiation between benign and malignant lesions and early detection of any malignant transformation in premalignant lesion are extremely important for further management decisions. Diagnostic cytology has limited sensitivity to further differentiate between benign, premalignant, and malignant lesions of the pancreas. There is limited information about the epidemiological risk factors and molecular mechanisms leading to development and further progression to malignancy of IPMNs. Several studies have shown that pancreatic juice and pancreatic tissue from the lesion can be tested for molecular markers including K-ras, p53, and p16 to differentiate between cancer and chronic inflammatory process. We review cellular signaling pathways that contribute to pathogenesis of IPMNs of the pancreas to further identify potential biomarkers and molecular targets.

RNA interference suppression of mucin 5AC (MUC5AC) reduces the adhesive and invasive capacity of human pancreatic cancer cells

BACKGROUND

MUC5AC is a secretory mucin normally expressed in the surface muconous cells of stomach and bronchial tract. It has been known that MUC5AC de novo expression occurred in the invasive ductal carcinoma and pancreatic intraepithelial neoplasm with no detectable expression in normal pancreas, however, its function remains uncertain. Here, we report the impact of MUC5AC on the adhesive and invasive ability of pancreatic cancer cells.

METHODS

We used two MUC5AC expressing cell lines derived from human pancreatic cancer, SW1990 and BxPC3. Small-interfering (si) RNA directed against MUC5AC were used to assess the effects of MUC5AC on invasion and adhesion of pancreas cancer cells in vitro and in vivo. We compared parental cells (SW1990 and BxPC3) with MUC5AC suppressed cells by si RNA (si-SW1990 and si-BxPC3).

RESULTS

MUC5AC was found to express in more than 80% of pancreatic ductal carcinoma specimens. Next we observed that both of si-SW1990 and si-BxPC3 showed significantly lower adhesion and invasion to extracellular matrix components compared with parental cell lines. Expression of genes associated with adhesion and invasion including several integerins, matrix metalloproteinase (MMP) -3 and vascular endothelial growth factor (VEGF) were down-regulated in both MUC5AC suppressed cells. Furthermore, production of VEGF and phosphorylation of VEGFR-1 were significantly reduced by MUC5AC down regulation. Both of si-SW1990 and si-BxPC3 attenuated activation of Erk1/2. In vivo, si-SW1990 did not establish subcutaneous tumor in nude mice.

CONCLUSIONS

Knockdown of MUC5AC reduced the ability of pancreatic cancer cells to adhesion and invasion, suggesting that MUC5AC might contribute to the invasive motility of pancreatic cancer cells by enhancing the expression of integrins, MMP-3, VEGF and activating Erk pathway.

Update on the molecular pathogenesis of pancreatic tumors other than common ductal adenocarcinoma

PURPOSE

Although ductal adenocarcinoma is the most common and well known pancreatic tumor type, other distinct epithelial neoplasms affecting the pancreas that show different symptoms, biological behaviors and outcomes are becoming more frequently recognized and documented. Pancreatic epithelial tumors may be separated into ductal and nonductal neoplasms. The former group includes pancreatic ductal adenocarcinoma, intraductal papillary-mucinous tumor, mucinous cystic tumor and serous cystic tumor. The latter group includes pancreatic endocrine tumor, pancreatic acinar cell carcinoma, pancreatoblastoma and solid-pseudopapillary tumor. The aim of this review is to summarize recently acquired knowledge regarding the molecular characterization of these uncommon pancreatic epithelial neoplasms.

RECENT FINDINGS

Molecular studies of uncommon pancreatic epithelial tumors suggest that the different morphological entities are associated with distinct molecular profiles, highlighting the involvement of different molecular pathways leading to the development of each subtype of pancreatic neoplasm.

CONCLUSION

The correct classification of rare pancreatic epithelial tumors and the identification of their characteristic molecular aspects is the fundamental starting point in identifying novel diagnostic molecular tools and new targets for innovative therapeutic strategies.

Cystic neoplasms of the exocrine pancreas

The increasing use of radiological imaging has led to greater detection of small and asymptomatic cystic lesions of the pancreas. Most are resectable, but not all are neoplastic. This review provides an update on the histopathology, immunohistochemistry, molecular biology, pathogenesis and management of cystic neoplasms of the exocrine pancreas. These include the serous, the mucinous cystic, the intraductal papillary mucinous and the solid pseudopapillary neoplasms. Recently reported variants are described and very rare cystic variants of other pancreatic epithelial and mesenchymal neoplasms are briefly mentioned.