Person:

Lauwers, Gregory Y.

Autoimmune pancreatitis (AIP) shows a unique spectrum of histologic features and commonly presents with an abundant IgG4-positive (IgG4+) plasma cell infiltration. However, differentiating AIP from other mass lesions, particularly pancreatic cancer [invasive ductal carcinoma (IDC)] can be clinically challenging. In this study, we evaluated the validity of IgG4 and IgG immunohistochemistry of ampullary and periampullary tissue for the diagnosis of AIP. Our study group consisted of 14 resected AIP cases with appropriate ampullary sections. Superficial ampullary tissue and "shouldering" duodenal mucosa were evaluated for several histologic variables. Immunohistochemistry for IgG4 and IgG was performed. The number of IgG4 and IgG-positive plasma cells was counted and an IgG4+ to IgG+ plasma cells ratio (IgG4/IgG ratio) was evaluated. A control cohort was composed of IDC (n=30) and chronic pancreatitis (CP) (n=29). Although an overlap was present between the groups, the overall inflammation and number of plasma cells in and around the ampulla was significantly increased in AIP compared with CP and IDC. Furthermore, although there was some overlap in the crude number of IgG4+ plasma cells of the ampullary and duodenal tissue between AIP, IDC, and CP, an IgG4/IgG ratio, especially of the ampulla, seems diagnostically useful in differentiating AIP from other "mass forming" lesions. When a cut-off of 0.10 was applied, the diagnostic sensitivity and specificity of the ampullary IgG4/IgG ratio was 86% and 95%, respectively. In conclusion, evaluation of ampullary histology and IgG4/IgG ratio might be proven beneficial in discriminating AIP from other mass forming pancreatic lesions.

Gastric adenocarcinoma is the second leading cause of cancer death worldwide. Epstein–Barr virus (EBV) is present in the malignant cells of approximately 10% of cases. It is unclear whether EBV is being missed in some gastric adenocarcinomas due to insensitive test methods or partial EBV genome loss. In this study, we screened 113 gastric adenocarcinomas from low- and high-incidence regions (United States and Central America) for the presence of EBV using a battery quantitative real-time PCR (Q-PCR) assays targeting disparate segments of the EBV genome (BamH1W, EBNA1, LMP1, LMP2, BZLF1, EBER1) and histochemical stains targeting EBV-encoded RNA (EBER), the latent proteins LMP1 and LMP2, and the lytic proteins BMRF1 and BZLF1. EBV DNA was detected by Q-PCR in 48/75 United States cancers (64%) and in 38/38 Central American cancers (100%), which was a significant differrence. EBER was localized to malignant epithelial cells in 8/48 (17%) United States and 3/38 (8%) Central American cancers. Viral loads were considerably higher for EBER-positive vs EBER-negative cancers (mean 162 986 vs 62 EBV DNA copies per 100 000 cells). A viral load of 2000 copies per 100 000 cells is recommended as the threshold distinguishing EBER-positive from EBER-negative tumors. One infected cancer selectively failed to amplify the LMP2 gene because of a point mutation, whereas another cancer had an atypical pattern of Q-PCR positivity suggesting deletion of large segments of the EBV genome. Three different viral latency profiles were observed in the cancers based on constant expression of EBER and focal or variable expression of LMP1 or LMP2, without lytic protein expression. We conclude that EBV DNA levels generally reflect EBER status, and a panel of at least two Q-PCR assays is recommended for sensitive identification of infected cancers.

OBJECTIVES: Photodynamic therapy (PDT) is increasingly used for the treatment of patients with Barrett's esophagus (BE) with dysplasia or early carcinoma. Post-PDT, some patients show residual BE either exposed to the luminal surface (nonburied) or buried underneath reepithelialized squamous mucosa (buried BE). Buried BE may be a serious clinical problem since it can go unnoticed during surveillance endoscopies. The neoplastic potential of buried BE is poorly understood. The aim of this study was to evaluate the biological characteristics of nonburied and buried BE in patients treated with PDT. METHODS: Twelve patients selected from a cohort of 52 BE patients who received PDT for high-grade dysplasia or intramucosal adenocarcinoma were used for this study because they all had both pre- and post-PDT (nonburied), and post-PDT buried, BE biopsies, without dysplasia, available for analysis. The biopsies were immunostained for Ki-67, p53, cyclin D1, bcl-2, TGF-alpha, EGFR, and AMACR. High fidelity DNA histograms were obtained by image cytometry analysis of Feulgen stained slides, and used to determine peak DNA index (DI), DNA heterogeneity, and 5N exceeding rate (5NER). Comparisons were made between pre-PDT nonburied BE and post-PDT nonburied and buried BE. RESULTS: Pre-PDT BE showed an elevated Ki-67 crypt proliferation rate (43.3%) and p53, bcl-2, TGF-alpha, and EGFR positivity in 8%, 25%, 75%, and 25% of cases, respectively. Cyclin D1 and AMACR were negative in all cases. High fidelity DNA histograms showed mild aneuploidy in 73% of cases. Post-PDT buried BE showed a significantly lower Ki-67 crypt proliferation rate (29.9%) in comparison to nonburied BE, in both pre- PDT (43.3%) and post-PDT (44.4%) biopsies (P < 0.05), but similar rates of positivity for the other peptide markers. In contrast to pre-PDT nonburied BE biopsies, high fidelity DNA histograms revealed that none of the buried BE (0%), and only 2/9 (11%) nonburied BE post-PDT, showed aneuploidy. CONCLUSIONS: Pre-PDT nonburied BE, without dysplasia, shows elevated crypt proliferation and mild, but frequent, DNA content abnormalities. Post-PDT, nonburied BE shows persistently elevated crypt proliferation, but significantly less frequent DNA content abnormalities, whereas buried BE shows decreased crypt proliferation and normal DNA content profile. These results suggest that post-PDT buried BE may have a lower neoplastic potential than pre-PDT BE.

Microsatellite instability (MSI) has been reported in various tumors, with colon cancer as the prototype. However, little is known about MSI in Barrett esophagus (BE)-associated adenocarcinoma. Thus, the aim of this study was to compare the clinicopathologic and molecular features of BE-associated adenocarcinomas with and without MSI. The study cohort consisted of 76 patients with BE-associated adenocarcinomas (66 male, 10 female), with a mean age of 65.1 years. Immunohistochemistry (IHC) for MLH1, MSH2, MSH6, PMS2, and CD3 and in situ hybridization for Epstein-Barr virus-encoded RNA were performed. MLH1 and PMS2 expression was lost by IHC in 5 cases (6.6%); of these, 5 showed high-level MSI (MSI-H) by polymerase chain reaction assay, and 4 showed hMLH1 promoter methylation. Histologically, tumors with MSI-H were heterogenous and included conventional adenocarcinomas with tumor-infiltrating lymphocytes (n=1), medullary carcinoma (n=2), signet ring cells (n=1), and signet ring cell and mucinous components (n=1). Compared with tumors negative for MSI by IHC, BE-associated adenocarcinomas with MSI-H were associated with older patient age (P=0.0060), lymphovascular invasion (P=0.027), and significantly larger numbers of tumor-infiltrating lymphocytes (P<0.0001). However, there was no statistical difference in overall survival between the 2 groups (P=0.285). In conclusion, MSI-H is uncommon in BE-associated adenocarcinomas, but is associated with clinicopathologic features fairly similar to sporadic microsatellite unstable colorectal cancers. Given the growing evidence that indicates lack of benefits from adjuvant therapy with fluorouracil in the colonic counterpart, it may be important to identify MSI-H in BE-associated adenocarcinomas.

Spectrally encoded confocal microscopy and optical frequency domain imaging are two non-contact optical imaging technologies that provide images of tissue cellular and architectural morphology, which are both used for histopathological diagnosis. Although spectrally encoded confocal microscopy has better transverse resolution than optical frequency domain imaging, optical frequency domain imaging can penetrate deeper into tissues, which potentially enables the visualization of different morphologic features. We have developed a co-registered spectrally encoded confocal microscopy and optical frequency domain imaging system and have obtained preliminary images from human oesophageal biopsy samples to compare the capabilities of these imaging techniques for diagnosing oesophageal pathology.

Objective: To determine whether intraductal papillary mucinous neoplasms of the pancreas (IPMNs) have a different genetic background compared with ductal adenocarcinoma (PDAC). Summary Background Data: The biologic and clinical behavior of IPMNs and IPMN-associated adenocarcinomas is different from PDAC in having a less aggressive tumor growth and significantly improved survival. Up to date, the molecular mechanisms underlying the clinical behavior of IPMNs are incompletely understood. Methods: 128 cystic pancreatic lesions were prospectively identified during the course of 2 years. From the corresponding surgical specimens, 57 IPMNs were separated and subdivided by histologic criteria into those with low-grade dysplasia, moderate dysplasia, high-grade dysplasia, and invasive cancer. Twenty specimens were suitable for DNA isolation and subsequent performance of array CGH. Results: While none of the IPMNs with low-grade dysplasia displayed detectable chromosomal aberrations, IPMNs with moderate and high-grade dysplasia showed frequent copy number alterations. Commonly lost regions were located on chromosome 5q, 6q, 10q, 11q, 13q, 18q, and 22q. The incidence of loss of chromosome 5q, 6q, and 11q was significantly higher in IPMNs with high-grade dysplasia or invasion compared with PDAC. Ten of 13 IPMNs with moderate dysplasia or malignancy had loss of part or all of chromosome 6q, with a minimal deleted region between linear positions 78.0 and 130.0. Conclusions: This study is the first to use array CGH to characterize IPMNs. Recurrent cytogenetic alterations were identified and were different than those described in PDAC. Array CGH may help distinguish between these 2 entities and give insight into the differences in their biology and prognosis.

Endoscopic mucosal resection (EMR) is being advocated as a diagnostic, staging, and therapeutic technique for the management of Barrett esophagus (BE)-related neoplasia. With the emergence of new endoluminal therapy including EMR for the treatment of BE-related superficial adenocarcinomas, accurate staging has become crucial to select patients for different treatment arms. Intramucosal adenocarcinomas can be successfully treated by endoluminal techniques, whereas submucosal invasive tumors with a greater risk of lymph node metastasis are likely candidates for esophagectomy. Endoscopic ultrasound (EUS) is used to stage superficial BE-related neoplasms, yet endoscopic staging can be incongruent to that obtained after pathologic examination. In this study, we sought to determine morphologic factors, which may influence EUS staging in 35 cases with intramucosal adenocarcinoma diagnosed by subsequent EMR, focusing on tumor characteristics and structural changes associated with BE. Among the latter duplication of the muscularis mucosae, either fragmented or well-organized, was seen in 64% of 11 cases that were overstaged as having submucosal invasion by EUS, compared with 38% of those accurately staged. A greater vertical thickness of the tumor was also associated with overstaging by EUS (1.61+/-0.75 mm in the discordant vs. 1.16+/-0.67 mm in the concordant groups, P=0.028). The results illustrate how morphologic factors may affect EUS staging of superficial esophageal adenocarcinomas. EUS alone is not sufficient for staging these neoplasms precisely, and to accurately stratify patients into different treatment arms, EMR should play a role as a complementary staging modality.

Gastric epithelial dysplasia (GED) can be morphologically categorized into adenomatous (or intestinal) and foveolar (or gastric) types. Although limited genetic differences have been demonstrated between these subtypes, the expression of various mucins has not been systematically evaluated in this context. Endoscopic mucosal resections from 69 cases of GEDs were evaluated for the expression of MUC2, MUC5AC, MUC6, and CD10. The results were correlated with morphologic categorization and clinicopathologic parameters. GED was classified as adenomatous, foveolar, or hybrid (showing features of both types), on the basis of histologic evaluation. The neighboring intestinal metaplasia (IM) was also evaluated. An adenomatous morphology was seen in 45%, hybrid type in 33.3%, and a “pure” foveolar type was seen in 21.7% of the cases. Foveolar GED was often depressed/flat on endoscopy and showed a statistically significant association with high-grade morphology (P=0.046). Immunohistochemistry confirmed the histologic stratification. The foveolar and hybrid types were more often positive for MUC5AC (P=0.0001 for both) and negative for CD10 (P=0.019 and 0.016, respectively) as compared with adenomatous GED. High-grade morphology was associated with MUC5AC expression regardless of the morphologic phenotype (P=0.026). Foveolar (73.3%) and hybrid (86.9%) GEDs were associated more often with IM showing a retained expression of gastric type mucin than adenomatous GED (29%) (P<0.01 for both). In contrast, adenomatous type (58.1%) of GED was significantly associated with IM showing a complete intestinal phenotype (CD10+) compared with the foveolar (13.3%) and hybrid types (17.4%) of GED (P=0.005 for both comparisons). In conclusion, our study indicates that foveolar and adenomatous types of GED have distinct clinicopathologic features, mucin profiles, and association with different types of IM.

Monoclonal antibodies (mAbs) against the cytotoxic T lymphocyte antigen-4 (CTLA-4) molecule are used as an adjuvant to experimental tumor immunization protocols in the treatment of malignant melanomas and ovarian cancers. Aside from noted early therapeutic successes, a spectrum of adverse effects, including severe gastroenteritis, has been reported. We report herein our observations of 5 patients who developed severe gastrointestinal toxicity affecting the gastric, small intestinal, and colonic mucosa. The endoscopic findings were variable, ranging from normal to diffusely erythematous and ulcerated mucosa. The constant histologic findings included a lymphoplasmacytic expansion of the lamina propria with increase in intraepithelial lymphocytes. Increased epithelial apoptosis was also a distinctive feature. Cryptitis and glandular inflammation were observed in the colon, ileum, and stomach, whereas villous blunting was present in the ileal and duodenal mucosa. Immunohistochemical analysis revealed a marked increase of all T-cell subsets (CD3+, CD4+, and CD8+) and of CD4CD25 regulatory T cells. We conclude that the panenteritis associated with injection of alpha-CTLA-4 mAbs demonstrates histology resembling autoimmune enteropathy. Furthermore, although the pathogenesis of immune dysregulation after the infusion of alpha-CTLA-4 mAbs remains unclear, we suspect that the increased number of regulatory T cells in the gastrointestinal mucosa may play a role in the pathogenicity.

CDX2 is an intestinal transcription factor responsible for regulating the proliferation and differentiation of intestinal epithelial cells. In gastric adenocarcinoma, CDX2 expression is known to be associated with limited invasiveness and intestinal phenotypes. The aims of this study were to analyze CDX2 expression in a series of well-characterized cases of gastric epithelial dysplasia, based on the morphologic and mucin phenotypes, and also to analyze CDX2 expression along the metaplasia–dysplasia–carcinoma sequence. CDX2 expression was evaluated in 69 cases of gastric epithelial dysplasia, 88 cases of intestinal-type early gastric cancers, and 56 cases of advanced gastric cancers. Increased CDX2 expression was more frequently associated with adenomatous-type gastric epithelial dysplasia (27/31, 87%) compared with foveolar (7/15, 47%) or hybrid (10/23, 44%) types of gastric epithelial dysplasia (P=0.001). CDX2 expression correlated with an increase in CD10 expression (P=0.005), and a decrease in MUC5AC expression (P=0.001) in gastric epithelial dysplasia. CDX2 expression was also gradually decreased from gastric epithelial dysplasia, to early and advanced gastric cancers (present in 64, 40 and 27% of the cases, respectively). A negative correlation was also observed between CDX2 expression and the depth of tumor invasion. Our results indicate that CDX2 expression is associated with specific morphological and mucin phenotypes of gastric epithelial dysplasias, and decreases progressively with the advancing stage of gastric cancers, suggesting a possible tumor suppressor role for CDX2.