Intestinal-type Intraductal Papillary Mucinous Neoplasms Research Articles

Syndrome de RESLES iatrogène aux antipsychotiques

Intraductal papillary mucinous neoplasms (IPMNs) constitute a group of rare conditions with a potential for malignant degeneration. The appearance of symptoms should suggest degeneration. This case demonstrates an unusual case of a patient presenting an intestinal type IPMN that was revealed by a large abdominal mass.47-year-old woman with a history of hydatid cyst of the liver. The patient was admitted to our hospital for management of large abdominal mass measuring 185 × 128*190 mm. Intra-operative findings showed a voluminous tumor, of approximately 20 cm in all its dimensions, with double solido-cystic component at the expense of the neck and the body of the pancreas. The patient underwent splenopancreatectomy. The histopathological examination confirmed the presence of intestinal type of IPMN of pancreas.Acute pancreatitis is revealed in the majority of cases of IPMNs, related to duct obstruction by secreting mucus plug. IPMNs are rarely the cause of a large abdominal mass. They are cystic lesions of slow evolution, macroscopically visible and rarely macrocystic, unlike serous cystadenoma. The tumor size is a powerful indicator of the malignancy of IPMNs. The current definitive and ideal treatment for main duct and mixed type IMPNs is a surgical resection.IPMNs are a cystic lesion, rarely revealed by a large mass.

A case of ectopic pancreas of the stomach accompanied by intraductal papillary mucinous neoplasm with GNAS mutation

BackgroundEctopic pancreas is basically a benign disease and is not always necessary to be removed. However, all types of neoplasms occurring in the normal pancreas such as ductal adenocarcinomas and intraductal papillary mucinous neoplasms (IPMNs) may develop even within ectopic pancreas. We recently encountered an extremely rare case of ectopic pancreas in the gastric antrum associated with IPMN possessing a GNAS mutation.Case presentationA 71-year-old Japanese woman complained of epigastric pain. Computed tomography and upper gastrointestinal endoscopy showed an intramural cystic mass in the antrum of the stomach. Endoscopic ultrasound-guided fine needle aspiration (EUS-FNA) biopsy did not give a definitive diagnosis, and the patient underwent resection of the lesion. Histology of the resected specimen showed that the gastric intramural lesion was ectopic pancreas. Moreover, the lesion contained dilated duct components with tubulo-villous epithelial proliferation consistent with pancreatic IPMN. Since the covering epithelial cells had highly atypical nuclei, the lesion was diagnosed as IPMN with high grade dysplasia. Immunohistochemistry showed that the IPMN component showed to be MUC2-, MUC5AC-, and CDX2-positive but MUC1- and MUC6-negative. Mutational analyses using genomic DNA revealed that the IPMN component had a mutation of GNAS at exon 8 (Arg201Cys).ConclusionWe finally diagnosed this case as gastric ectopic pancreas accompanied by intestinal type IPMN with high grade dysplasia possessing GNAS mutation. Although there were 17 cases of ectopic pancreas with IPMN including 6 cases of gastric ones reported in the English literature, this is the first case of ectopic pancreas with IPMN which was proved to have GNAS mutation. Intimate preoperative examinations including imaging analyses and EUS-FNA biopsy/cytology are recommended to decide whether the lesion has to be resected or not even if they are not effective for getting the right diagnosis.

Cytology adds value to monoclonal antibody Das-1 testing for detection of high-risk pancreatic cysts

Determining the risk of malignancy in a pancreatic cyst (PC) is a clinical and diagnostic challenge. Monoclonal antibody (mAb) Das-1 test was shown to have high sensitivity, specificity, and accuracy in detecting high-risk (HR) cysts. Das-1 mAb test detects HR mucinous cysts with high-grade dysplasia (HGD), invasive carcinoma, and/or intestinal-type epithelium. Correlation of mAb Das-1 testing of PC fluids with cytomorphologic findings has not been evaluated. We correlated cytology with mAb Das-1 test results and resection histology in 26 PCs. There were 18 intraductal papillary mucinous neoplasms (IPMN), 1 intraductal oncocytic papillary neoplasm (IOPN), 4 mucinous cystic neoplasms (MCN), 2 serous cystadenomas, and 1 cystic pancreatic neuroendocrine tumor (PanNET). HR cysts included cysts with high-grade atypia on cytology or HGD on histology, invasive carcinoma, IOPNs, and cystic PanNETs. Intestinal type IPMNs were also HR cysts on histology. In 17 cases (65.38%), cytology and mAb Das-1 test correlated with histology. There were 2 (7.69%) mAb Das-1 test negative HR PCs diagnosed by cytology. Five (19.23%) mAb Das-1 test positive HR PCs had mucin only or cells with low-grade dysplasia on cytology. Two mAb Das-1 test positive HR PCs had nondiagnostic cytology. HR IOPN and cystic PanNET were not detected by mAb Das-1 test. The mAb Das-1 is a sensitive and specific biomarker for detecting HR mucinous PCs. Adding cytology to mAb Das-1 testing improves the sensitivity for the detection of nonmucinous HR PC. Together, cytology with mAb Das-1 testing is more accurate than either one alone.

Cross Validation of the Monoclonal Antibody Das-1 in Identification of High-Risk Mucinous Pancreatic Cystic Lesions

Although pancreatic cystic lesions (PCLs) are frequently and incidentally detected, it is a challenge to determine their risk of malignancy. In immunohistochemical and enzyme-linked immunosorbent assay (ELISA) analyses of tissue and cyst fluid from pancreatic intraductal papillary mucinous neoplasms, the monoclonal antibody Das-1 identifies those at risk for malignancy with high levels of specificity and sensitivity. We aimed to validate the ability of Das-1 to identify high-risk PCLs in comparison to clinical guidelines and clinical features, using samples from a multicenter cohort. We obtained cyst fluid samples of 169 PCLs (90 intraductal papillary mucinous neoplasms, 43 mucinous cystic neoplasms, and 36 non-mucinous cysts) from patients undergoing surgery at 4 tertiary referral centers (January 2010 through June 2017). Histology findings from surgical samples, analyzed independently and centrally re-reviewed in a blinded manner, were used as the reference standard. High-risk PCLs were those with invasive carcinomas, high-grade dysplasia, or intestinal-type intraductal papillary mucinous neoplasms with intermediate-grade dysplasia. An ELISA with Das-1 was performed in parallel using banked cyst fluid samples. We evaluated the biomarker's performance, generated area under the curve values, and conducted multivariate logistic regression using clinical and pathology features. The ELISA for Das-1 identified high-risk PCLs with 88% sensitivity, 99% specificity, and 95% accuracy, at a cutoff optical density value of 0.104. In 10-fold cross-validation analysis with 100 replications, Das-1 identified high-risk PCLs with 88% sensitivity and 98% specificity. The Sendai, Fukuoka, and American Gastroenterological Association guideline criteria identified high-risk PCLs with 46%, 52%, and 74% accuracy (P for comparison to Das-1 ELISA <.001). When we controlled for Das-1 in multivariate regression, main pancreatic duct dilation >5 mm (odds ratio, 14.98; 95% confidence interval, 2.63-108; P < .0012), main pancreatic duct dilation ≥1 cm (odds ratio, 47.9; 95% confidence interval, 6.39-490; P < .0001), and jaundice (odds ratio, 6.16; 95% confidence interval, 1.08-36.7; P= .0397) were significantly associated with high-risk PCLs. We validated the ability of an ELISA with the monoclonal antibody Das-1 to detect PCLs at risk for malignancy with high levels of sensitivity and specificity. This biomarker might be used in conjunction with clinical guidelines to identify patients at risk for malignancy.

GNAS but Not Extended RAS Mutations Spectrum are Associated with a Better Prognosis in Intraductal Pancreatic Mucinous Neoplasms.

The management of intraductal papillary mucinous neoplasms (IPMNs) is mainly based on imaging features and clinical symptoms, and remains challenging. The aim of this study was to assess GNAS, RAS family (KRAS, NRAS and HRAS), BRAF, and PIK3CA mutation status in resected IPMNs and correlate it with clinicopathological characteristics and patient survival. Overall, 149 consecutive unselected patients who underwent pancreatectomy for IPMNs were included. After dissection from formalin-fixed and paraffin-embedded tumors, GNAS mutational screening was assessed by allelic discrimination using Taqman® probes and confirmed by SNaPshot analysis. RAS family, BRAF, and PIK3CA mutational screening was assessed by high resolution melt and Sanger sequencing. Gastric- and intestinal-type IPMNs were the most frequent lesions (52% and 41%, respectively). Intestinal-type IPMNs were more frequently associated high-grade dysplasia (49%) and were the only IPMNs associated with colloid-type carcinoma. All pancreatobiliary IPMNs were invasive lesions, located in the main pancreatic duct. GNAS-activating mutations were strongly associated with the intestinal phenotype (p < 10-4), while RAS pathway mutations were not associated with any particular phenotype. Mutations within other members of the epidermal growth factor receptor (EGFR) pathway were very rare (2%). GNAS-mutated IPMNs were rarely invasive (11%) and almost exclusively (83%) of the colloid type. For invasive lesions, multivariate analyses determined that only node negativity was associated with improved cancer-specific survival, but, in univariate analysis, GNAS mutation was associated with prolonged survival. In patients selected for surgery, GNAS mutation analysis and tumor phenotype can help to better predict patient prognosis. In the near future, a more precise mutational analysis of IPMNs might help to better tailor their management.

Malignant transformation and overall survival of morphological subtypes of intraductal papillary mucinous neoplasms of the pancreas: A network meta-analysis

BackgroundEmerging evidence suggests the predictive role of morphological subtypes (gastric, intestinal, pancreatobiliary, and oncocytic) of intraductal papillary mucinous neoplasms (IPMNs) in malignant transformation and overall survival. But results of these studies are currently discordant. MethodsA comprehensive literature search in MEDLINE, EMBASE, and Cochrane Central Register of Controlled Trials (CENTRAL) was conducted for eligible studies. Network meta-analysis using the random-effect model was carried out to detect differences in incidences of invasive IPMNs and hazard ratios from survival curves among four morphological subtypes. Results19 studies were included in the network comparison. The outcomes showed that pancreatobiliary-type (OR for odds ratio=25.87, 95% CI: 12.11–52.10, compared with gastric-type) and oncocytic-type (OR=18.59, 95% CI: 7.18–42.74) IPMNs had the highest risks of progressing to invasive IPMNs, followed by intestinal-type (OR=5.71, 95% CI: 2.85–10.61) and gastric-type IPMNs. With the gastric type as the baseline, pancreatobiliary-type IPMNs were found to have the worst prognosis (HR for hazard ratio=5.05, 95% CrI: 1.33–13.47) while no significant differences were found for the intestinal type (HR=1.90, 95% CrI: 0.59–4.58) and the oncocytic type (HR=3.29, 95% CrI: 0.75–9.71). ConclusionIt is suggested that pancreatobiliary-type IPMNs are the most likely to become invasive and are associated with poor prognosis. In contrast, the other three subtypes have similar overall survivals even though the oncocytic- and intestinal-type IPMNs are predisposed to be more invasive than gastric-type IPMNs.

Acute pancreatitis in intraductal papillary mucinous neoplasms: A common predictor of malignant intestinal subtype

Acute pancreatitis (AP) is a common presenting symptom of intraductal papillary mucinous neoplasms (IPMN). Our objective was to evaluate the clinical and pathologic features of IPMN that present with AP. We hypothesized that the intestinal epithelial subtype, which produces a highly viscous mucin containing MUC2 glycoprotein, is associated with the development of AP. We performed a case-control study, evaluating 325 patients with IPMN resected at our institution. Clinicopathologic features were assessed for patients with and without a history of AP and compared between the 2 groups. A history of AP was found in 69 patients (21%). Of those, 33 (48%) experienced a single episode, and some patients had as many as 10 distinct attacks. Three patients presented with necrotizing pancreatitis requiring operative debridement. After resection, recurrent AP occurred in only 14%. A history of AP was associated with younger age (61 vs 70, P < .001), main duct involvement (odds ratio [OR] 1.73, 95% confidence interval [95% CI] 1.00-3.01; P = .049), intestinal subtype (OR 4.84, 95% CI 2.71-8.67; P < .001), and high-grade dysplasia (OR 1.82, 95% CI 1.07-3.11; P = .028). On multivariate analysis, AP was an independent predictor of intestinal subtype (OR 4.69, 95% CI 2.48-8.84, P < .001), malignancy (OR 1.97, 95% CI 1.07-3.63, P = .029), and main duct involvement (OR 1.87, 95% CI 1.02-3.43, P = .044). AP is a frequent presenting symptom of IPMN. These patients are younger and have greater odds of harboring malignant intestinal-type IPMN involving the main pancreatic duct.

GNAS mutation is a frequent event in pancreatic intraductal papillary mucinous neoplasms and associated adenocarcinomas.

In contrast to pancreatic ductal adenocarcinomas (PDAs), intraductal papillary mucinous neoplasms (IPMNs) frequently harbour GNAS mutations. To characterise GNAS-mutated pancreatic carcinomas, we examined mutations of GNAS and KRAS in 290 pancreatic adenocarcinomas and 77 pancreatic intraepithelial neoplasias (PanINs). In 64 % (39/61) of IPMNs and 37 % (11/30) of IPMN-associated adenocarcinomas, a GNAS mutation was found. GNAS mutations were frequent (78 %, 7/9) in mucinous carcinomas, with or without associated IPMN. In contrast, GNAS mutations were rarely observed in PDAs (1 %, 1/88) and PanINs (3 %, 2/77), and not at all in mucinous cystic neoplasms (MCNs) (0/10), neuroendocrine neoplasms (0/52), acinar cell neoplasms (0/16), serous cystadenomas (0/10), and solid-pseudopapillary neoplasms (0/14). We found GNAS mutations in 55/91 IPMNs with or without associated invasive carcinoma, solely in intestinal-type (78 %, 21/27) and gastric-type (62 %, 34/55) IPMNs. Of the IPMN-associated adenocarcinomas, mucinous-subtype tumours harboured GNAS mutations more frequently (83 %, 5/6) than tubular-subtype tumours (25 %, 6/24) (p = 0.02). We separately analysed GNAS in the adenocarcinoma and the IPMN component in the IPMN-associated adenocarcinomas. In all mucinous-subtype tumours, the two components exhibited identical genotypes. In contrast, the two components in 8 of 24 tubular-subtype tumours exhibited different genotypes, indicating intratumour heterogeneity. In conclusion, mucinous carcinomas with or without associated IPMN as well as IPMNs frequently harbour a GNAS mutation, reinforcing the notion that these constitute a spectrum of pancreatic tumours. Clinically and pathologically, these tumours are associated, but GNAS mutation sheds further light on this spectrum.

Abstract 1897: Application of a novel DNA methylation analysis method (MSE) for mucin expression in pancreatic juices for diagnosis of pancreatic neoplasms

Abstract Mucins play crucial roles in diagnostic and prognostic prediction and in carcinogenesis and tumor invasion. In our clinicopathological investigation for mucin expression in human pancreatic ductal adenocarcinomas (PDACs) and intraductal papillary mucinous neoplasms (IPMNs), we had reported that MUC1 (pan-epithelial membrane mucin) or MUC4 (tracheobronchial mambrane mucin) expression is related with the aggressive behavior and a poor outcome of the patients, whereas MUC2 (intestinal secretory mucin) expression tends to be related with the indolent behavior and a favorable outcome of the patients. We investigated the mechanism of mucin genes expression from the DNA methylation standpoint in human cancer cell lines using the mapping of methylated cytosines by the quantitative MassARRAY analysis, followed by the confirmation with MSP analysis and a novel DNA methylation analysis method ‘methylation specific electrophoresis (MSE, international patent open: WO 2011/132798)’, and compared the results with expression levels of mucin core protein and mRNA in the cancer cells. The results obtained showed that MUC1, MUC2 and MUC4 expression is regulated by DNA methylation at their proximal 5′ flanking regions in the cancer cells. The MSE method greatly decreases the amount of input DNA, although conventional analytical methods for DNA methylation require a large amount of DNA and have low sensitivity. The lower detection limit for distinguishing different methylation status is under 0.1% and the detectable minimum amount of DNA is 20 pg, which can be obtained from only a few cells. We applied the MSE method to human pancreatic juices from 45 patients with various pancreatic lesions. The analyses for DNA methylation status of MUC1, MUC2 and MUC4 combined with image data were useful for differential diagnosis of various human pancreatic neoplasms. The examination of 45 samples of human pancreatic juices by the MSE method combined with the image examination showed the following specificity and sensitivity by quadratic discrimination analysis: PDAC, 87% and 80%; gastric-type IPMN (safe type), 88% and 77%; intestinal-type IPMN (dangerous type), 100% and 88%; respectively. The MSE analysis of human pancreatic juices may give us very useful informations for the selection of the treatment methods for pancreatic neoplasms. Citation Format: Suguru Yonezawa, Seiya Yokoyama, Michiyo Higashi. Application of a novel DNA methylation analysis method (MSE) for mucin expression in pancreatic juices for diagnosis of pancreatic neoplasms. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 1897. doi:10.1158/1538-7445.AM2014-1897

Diagnosis of pancreatic neoplasms using a novel method of DNA methylation analysis of mucin expression in pancreatic juice.

Mucins (MUC) play crucial roles in carcinogenesis and tumor invasion in pancreatic ductal adenocarcinoma (PDAC) and intraductal papillary mucinous neoplasms (IPMNs). Our immunohistochemistry (IHC) studies have shown a consensus position on mucin expression profiles in pancreatic neoplasms as follows: MUC1-positive but MUC2-negative expression in PDACs; MUC1-negative but MUC2-positive expression in intestinal-type IPMNs (dangerous type); MUC1-negative and MUC2-negative expression in gastric-type IPMNs (safe type); High MUC4 expression in PDAC patients with a poor outcome; and MUC4-positive expression in intestinal-type IPMNs. We also showed that three mucin genes (MUC1, MUC2 and MUC4) expression in cancer cell line was regulated by DNA methylation. We have developed a novel ‘methylation-specific electrophoresis (MSE)’ method to analyze the DNA methylation status of mucin genes by high sensitivity and resolution. By using the MSE method, we evaluated pancreatic juice samples from 45 patients with various pancreatic lesions. The results were compared with final diagnosis of the pancreatic lesions including IHC of mucin expression in the paired pancreatic tissues. The results indicated that the DNA methylation status of MUC1, MUC2 and MUC4 in pancreatic juice matched with the mucin expression in tissue. Analyses of the DNA methylation status of MUC1, MUC2 and MUC4 were useful for differential diagnosis of human pancreatic neoplasms, with specificity and sensitivity of 87% and 80% for PDAC; 100% and 88% for intestinal-type IPMN; and 88% and 77% for gastric-type IPMN, respectively. In conclusion, MSE analysis of human pancreatic juice may provide useful information for selection of treatment for pancreatic neoplasms.

Reappraisal of the Immunophenotype of Pancreatic Intraductal Papillary Mucinous Neoplasms (IPMNs)-Gastric Pyloric and Small Intestinal Immunophenotype Expression in Gastric and Intestinal Type IPMNs-.

Pancreatic intraductal papillary mucinous neoplasms (IPMNs) are mucin-producing neoplasms of the main and/or branch pancreatic ducts. To assess differences between various IPMN subtypes, immunohistochemical markers of gastric surface mucous cells (MUC5AC), gastric gland mucous cells (MUC6 and GlcNAcα1→4Galβ→R), gastric pyloric and duodenal epithelial cells (PDX1), intestinal cells (MUC2 and CDX2), small intestinal cells (CPS1) and large intestinal cells (SATB2) were evaluated in 33 surgically treated IPMNs. MUC2 expression classified IPMNs into gastric (n=17), intestinal (n=8) and mixed gastric and intestinal type (collision=7, composite=1). No differences in age or sex were observed among these types. MUC5AC and PDX1 were expressed in all IPMNs. MUC6 expression was higher in gastric and mixed types than in intestinal type. GlcNAcα1→4Galβ→R was detected in gastric and mixed type, but not in intestinal type. MUC2 and CDX2 expression were higher in intestinal type than gastric and mixed type. CPS1 expression was higher in intestinal type than gastric type. SATB2 was not observed in any IPMNs. Frequent abrupt transition between the two IPMN types in mixed-type IPMNs was observed. Gastric pyloric and small intestinal differentiation are characteristic of gastric and intestinal type IPMN, respectively, and these two IPMN types may have distinct pathogenesis.

Liver-Intestine Cadherin Expression Is Associated with Intestinal Differentiation and Carcinogenesis in Intraductal Papillary Mucinous Neoplasm

Objectives: Intraductal papillary mucinous neoplasms (IPMN) are classified into four phenotypes according to the WHO classification. Recently, intestinal-type IPMN has been suggested to grow with a distinct carcinogenetic pathway. Like mucin 2, oligomeric mucus/gel forming (MUC2) and caudal-related homeobox 2 (CDX2), liver-intestine cadherin (LI cadherin) is an intestine-specific marker. We aimed to investigate the roles of LI cadherin expression in IPMN. Methods: We examined LI cadherin expression in 135 cases of IPMN by immunohistochemical staining and the quantitative real-time reverse-transcription polymerase chain reaction. Results: LI cadherin protein and mRNA levels were significantly higher in intestinal-type IPMN than in nonintestinal-type IPMN (protein level, p < 0.001; mRNA level, p = 0.0312). A positive correlation was found between protein and mRNA of LI cadherin (p = 0.0037). The positivity rates of LI cadherin expression were significantly higher in CDX2-positive cases than in CDX2-negative cases (p < 0.001). In 41 intestinal-type IPMNs, LI cadherin-positive rates tended to increase gradually, from IPMN with low-grade dysplasia (IPMN-L) to IPMN with an associated invasive carcinoma (IPMN-IC) [IPMN-L vs. IPMN with high-grade dysplasia (IPMN-H); p = 0.0357, IPMN-L vs. IPMN-IC; p = 0.0230] and positively correlated with the Ki-67 labeling index (p = 0.0408), whereas this tendency was not recognized in nonintestinal-type IPMNs. Conclusions: LI cadherin is associated with an intestinal phenotype and an ‘intestinal pathway’ of carcinogenesis in IPMN.

Claudin-18 Is an Early-Stage Marker of Pancreatic Carcinogenesis

Pancreatic ductal neoplasms exhibit gastric epithelium-like characteristics. In this study, we evaluated the expression of claudin-18 (CLDN18), a gastric epithelium-associated claudin, in pancreatic intraepithelial neoplasias (PanINs), intraductal papillary mucinous neoplasms (IPMNs), mucinous cystic neoplasms (MCNs), and pancreatic ductal adenocarcinomas (PDACs) using immunohistochemistry. We observed a high level of expression of CLDN18 in PanINs (31/32, 97%), IPMNs (61/65, 95%), and MCNs (4/5, 80%) using ordinary tissue section analysis. Furthermore, we observed a high level of CLDN18 expression in PDACs (109/156, 70%) using tissue microarray analysis. However, the normal pancreatic duct or the ductal metaplasia of the acinar cells was not immunoreactive. Comparative analysis of CLDN18 and phenotypic markers in IPMNs revealed that simultaneous expression of CLDN18 and intestinal markers frequently occurred, even in intestinal-type IPMNs. CLDN18 variant 2 mRNA was expressed and was similarly upregulated by phorbol 12-myristate 13-acetate (PMA) treatment in pancreatic cancer cell lines and in a gastric cancer cell line. An inhibitor of pan-PKC (GF109203X) completely suppressed this upregulation in pancreatic cancer cells. These results indicate that CLDN18, a marker for the early carcinogenetic process, is commonly expressed in precursor lesions of PDAC. Activation of the PKC pathway might be involved in CLDN18 expression associated with pancreatic carcinogenesis.

Expression of claudin-4 (CLDN4) mRNA in intraductal papillary mucinous neoplasms of the pancreas

Claudin-4, encoding a protein for tight junction formation and function, is highly overexpressed in pancreatic ductal adenocarcinoma and is also associated with invasive adenocarcinomas arising in intraductal papillary mucinous neoplasms of the pancreas. However, the expression pattern of claudin-4 during neoplastic progression of intraductal papillary mucinous neoplasms remains unknown. Using quantitative real-time reverse transcription-PCR, we analyzed claudin-4 mRNA in a panel of 14 pancreatic cancer cell lines and in formalin-fixed paraffin-embedded tissues from 80 patients with intraductal papillary mucinous neoplasms of different histological grades and papillary subtypes. Increased expression of claudin-4 was confirmed in all the pancreatic cancer cell lines tested as compared with normal ductal epithelial cells and fibroblast cultures. The claudin-4 expression was significantly higher in high-grade intraductal papillary mucinous neoplasms (borderline neoplasm and carcinoma) than in low-grade intraductal papillary mucinous neoplasms (adenoma) (P<0.0001). In addition, claudin-4 mRNA levels were significantly higher in intestinal-type intraductal papillary mucinous neoplasms than in non-intestinal-type intraductal papillary mucinous neoplasms based on papillary subclassification (P<0.0001). Our findings suggest that claudin-4 expression is associated with neoplastic progression of intraductal papillary mucinous neoplasms and, especially, with a distinct pathway to intestinal differentiation.

A History of Acute Pancreatitis in Intraductal Papillary Mucinous Neoplasms of the Pancreas Is a Potential Predictive Factor for Malignant Papillary Subtype

Background/Aims: There are several reports regarding intraductal papillary mucinous neoplasms (IPMNs) detected after the occurrence of acute pancreatitis. Although the presence of symptoms is regarded as a factor for predicting malignant IPMNs, there have been few reports demonstrating whether a history of acute pancreatitis is a predictor of malignancy. The aim of this study was to evaluate the relationship between a history of acute pancreatitis and clinicopathological features of IPMNs including the papillary subtype. Methods: The data of 150 IPMNs resected between 1990 and 2009 were retrospectively reviewed. They were classified into IPMNs with or without history of acute pancreatitis, and then the clinicopathological features were compared between the 2 groups. Results: Nineteen (13%) of the 150 patients had a history of acute pancreatitis. Nine of them had repeated episodes of pancreatitis; however, severe pancreatitis was uncommon. The diameter of the main pancreatic duct of the pancreatitis group was significantly larger than that of the nonpancreatitis group (p = 0.04). The pancreatitis group had a significantly higher frequency of carcinoma derived from IPMNs than the nonpancreatitis group (p = 0.03). The incidence of intestinal-type IPMNs in the pancreatitis group was significantly higher than that in the nonpancreatitis group (p < 0.001). Conclusion: Acute pancreatitis associated with IPMNs could predict malignant intestinal-type tumor.

Intraductal Papillary-Mucinous Neoplasms of the Gastric and Intestinal Types May Have Less Malignant Potential Than the Pancreatobiliary Type

Intraductal papillary-mucinous neoplasms (IPMNs) of the pancreas are classified into 4 types--gastric, intestinal, pancreatobiliary, and oncocytic--on the basis of their morphology and immunohistochemistry. We classified IPMNs at our institute and used this classification to determine the clinicopathological features, prognosis, and malignant potential of the 4 types. Sixty-one patients with IPMN who underwent surgery between 2000 and 2007 were evaluated retrospectively. There were 24 tumors of the gastric type, 22 intestinal, 12 pancreatobiliary, and 3 oncocytic. Patients with the intestinal or gastric type had a better prognosis than those with the pancreatobiliary type. The intestinal and pancreatobiliary types had almost the same frequencies of carcinoma, but the intestinal type tended to have a lower frequency of invasive carcinoma than the pancreatobiliary type. Patients with invasive carcinomas derived from intestinal-type IPMNs tended to have a better prognosis than those whose invasive carcinomas were derived from the pancreatobiliary type. Intraductal papillary-mucinous neoplasm of the gastric and intestinal types may have less malignant potential than that of the pancreatobiliary type. Invasive carcinomas derived from intestinal-type IPMNs may be less invasive and slower growing than those derived from the pancreatobiliary type.

Preferential Expression of MUC6 in Oncocytic and Pancreatobiliary Types of Intraductal Papillary Neoplasms Highlights a Pyloropancreatic Pathway, Distinct From the Intestinal Pathway, in Pancreatic Carcinogenesis

The expression of different MUC glycoproteins has helped define cellular lineage in variety of pancreatic neoplasms, and has helped identify distinct carcinogenic pathways such as the intestinal pathway characterized by diffuse/strong MUC2/CDX2 expression in intestinal-type intraductal papillary mucinous neoplasms (IPMNs) and their associated colloid carcinomas (CCs). In this study, the expression profile of MUC6, a pyloric-type mucin, was investigated in both preinvasive and invasive pancreatic neoplasia. Florid papillary ("in-situ") components of 9 intraductal oncocytic papillary neoplasms (IOPNs), 24 IPMNs, and 7 mucinous cystic neoplasms (MCNs), were analyzed immunohistochemically for MUC6 expression, as were 15 PanINs, 112 usual invasive ductal adenocarcinomas (DAs), and 14 CCs. In PanINs, MUC6 expression was limited to the very early areas of PanIN-1A that typically have pyloric features. Expression was lost in later stages. Similarly, in IOPNs or IPMNs or MCNs, MUC6 expression was detectable in the cystic or flat areas that have pyloric-like histology. However, in the more advanced (papillary) components of these neoplasms, MUC6 expression was mostly limited to the "cuboidal-cell" but was not seen in the "columnar-cell" phenotype: there was diffuse or strong expression in 8/9 IOPN and, relatively weaker but consistent expression in all 6/6 pancreatobiliary-type IPMNs; whereas virtually no expression in villous or intestinal-type IPMNs. The 7/8 gastric or foveolar-type IPMNs were also negative; in the single case with positivity, the labeling was limited to high-grade dysplastic areas. Interestingly, the papillae in MCNs were also mostly negative. Among invasive carcinomas, 39/112 DAs and only 1/14 CC expressed MUC6. In DA, the expression did not correlate with survival (P=0.94), or any of the markers of aggressiveness: more than 2-cm tumor size (P=0.76), positive surgical margins (P=0.27), lymph node metastasis (P=0.82), or high grade (P=0.08). (1) The expression of MUC6 in oncocytic and pancreatobiliary-type neoplasms but not in villous or intestinal-type neoplasms supports the presence of a pyloropancreatic pathway distinct from the MUC2/CDX2 expressing intestinal pathway in intraductal papillary neoplasia. (2) MUC6 expression is present in the earliest (nonpapillary) form of any type of preinvasive neoplasia regardless of whether it is PanIN or IOPN or IPMN or MCN suggesting that these entities may share some characteristics early on, but evolve along divergent pathways as they progress.

CD44v6 Expression in Intraductal Papillary Mucinous Neoplasms of the Pancreas

The purpose of this study was to examine CD44v6 expression in intraductal papillary mucinous neoplasms (IPMNs) and clarify the role of CD44v6 in progression, invasion, metastasis, and morphogenesis of IPMNs. One hundred fifty-one samples of IPMNs and 30 normal controls were subjected to immunohistochemical analysis for CD44v6. The IPMNs were divided into 4 groups according to the grade of atypia (adenoma, borderline IPMN, noninvasive carcinoma, and invasive carcinoma) and 5 subtypes according to histological phenotype (gastric, intestinal, pancreatobiliary, oncocytic, and unclassified). Correlations were investigated between CD44v6 expression and clinicopathological characteristics including grade of atypia, subtype, lymph node metastasis, and invasion pattern. Whereas normal ductal epithelium did not express CD44v6, CD44v6 expression was observed from the early stage of IPMNs and up-regulated in the progression of IPMNs to invasive carcinoma. CD44v6 expression in intestinal-type IPMNs was significantly lower compared with that in other subtypes. Whereas no correlation was observed between lymph node metastasis and CD44v6 expression in invasive IPM carcinomas, the invasion pattern was significantly correlated to CD44v6 expression. The present data indicate that CD44v6 expression determines the morphology and aggressiveness of IPMNs and is involved in development and invasion of IPMNs.

MICRORNA MIR-155 IS A BIOMARKER OF EARLY PANCREATIC NEOPLASIA

Background: Intraductal papillary mucinous neoplasms (IPMNs) are non-invasive precursor lesions of pancreatic cancer. Misexpression of microRNAs (miRNAs) has emerged as a common feature of most human cancers, including pancreatic adenocarcinoma. In contrast, miRNA abnormalities in pancreatic cancer precursor lesions have not been systematically documented. Experimental Design: Relative expression levels of a panel of twelve miRNAs upregulated in pancreatic cancers were assessed in 15 microdissected non-invasive IPMNs versus matched normal pancreata, using quantitative reverse transcription PCR (qRT-PCR). Two significantly overexpressed miRNAs - miR-155 and miR-21 - were evaluated by locked nucleic acid in situ hybridization (LNA-ISH) in a panel of 64 archival IPMNs of all histological grades. The expression of miR-155 and miR-21 was also evaluated by qRT-PCR in pancreatic juice samples obtained from 10 patients with surgically resected IPMNs and five patients with non-neoplastic pancreato-biliary disorders ("disease controls"). Results: Significant overexpression by qRT-PCR of ten of the twelve miRNAs was observed in the 15 IPMNs versus matched controls (P < 0.05), with miR-155 (mean 11.6-fold) and miR-21 (mean 12.1-fold) demonstrating highest relative fold-changes in the precursor lesions. LNA-ISH confirmed the expression of miR-155 in 53 of 64 (83%) IPMNs compared to 4 of 54 (7%) normal ducts, and of miR-21 in 52 of 64 (81%) IPMNs compared to 1 of 54 (2%) normal ducts, respectively (P < 0.0001). A significantly higher proportion of IPMNs with carcinoma-in-situ expressed either miR-155 or miR-21, relative to IPMN adenomas (P < 0.01); in addition, miR-155 expression was demonstrable with significantly greater frequency in intestinal-type IPMNs (19 of 19, 100%) versus IPMNs with gastric foveolar-type lining (4 of 7, 57%) (P = 0.01). Upregulation of miR-155 transcripts by qRT-PCR was observed in 6 of 10 (60%) IPMN-associated pancreatic juice samples compared to 0 of 5 (0%) disease controls. Conclusions: Aberrant miRNA expression is an early event in the multistage progression of pancreatic cancer. Based on our results, miR-155 warrants further evaluation as a biomarker for IPMNs in clinical samples.