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Background: The tumor-expressed CD73 ectonucleotidase generates immune tolerance and promotes invasiveness via adenosine production from degradation of AMP. While anti-CD73 blockade treatment is a promising tool in cancer immunotherapy, a characterization of CD73 expression in human hepatobiliopancreatic system is lacking., Patients and Methods: CD73 expression was investigated by immunohistochemistry in a variety of non-neoplastic and neoplastic conditions of the liver, pancreas, and biliary tract., Results: CD73 was expressed in normal hepatobiliopancreatic tissues with subcellular-specific patterns of staining: canalicular in hepatocytes, and apical in cholangiocytes and pancreatic ducts. CD73 was present in all hepatocellular carcinoma (HCC), in all pancreatic ductal adenocarcinoma (PDAC), and in the majority of intra and extrahepatic cholangiocellular carcinomas, whereas it was detected only in a subset of pancreatic neuroendocrine neoplasms and almost absent in acinar cell carcinoma. In addition to the canonical pattern of staining, an aberrant membranous and/or cytoplasmic expression was observed in invasive lesions, especially in HCC and PDAC. These two entities were also characterized by a higher extent and intensity of staining as compared to other hepatobiliopancreatic neoplasms. In PDAC, aberrant CD73 expression was inversely correlated with differentiation (p < 0.01) and was helpful to identify isolated discohesive tumor cells. In addition, increased CD73 expression was associated with reduced overall survival (HR 1.013) and loss of E-Cadherin., Conclusions: Consistent CD73 expression supports the rationale for testing anti-CD73 therapies in patients with hepatobiliopancreatic malignancies. Specific patterns of expression could also be of help in the routine diagnostic workup.

Acinar cell carcinoma (ACC) is a rare pancreatic cancer which may be difficult to distinguish from other solid nonadenocarcinoma tumors. The diagnosis depends on the demonstration of acinar differentiation, obtained with antibodies recognizing various pancreatic enzymes that, although specific, show different sensitivity. The C-terminal portion of the BCL10 protein shows homology with carboxyl ester hydrolase (CEH), an enzyme produced by pancreatic acinar cells. We investigated the usefulness of a C-terminal BCL10 monoclonal antibody in the diagnosis of ACCs. We examined normal pancreases and different pancreatic tumors including ACCs, mixed acinar-endocrine carcinomas, ductal adenocarcinomas, mucinous, serous, solid pseudopapillary, and endocrine neoplasms. In addition, various normal tissues and cases of pancreatic metaplasia of the gastroesophageal mucosa, cases of ectopic pancreas, gastrointestinal endocrine tumors, salivary and breast acinic cell carcinomas, gastric adenocarcinomas with and without acinar differentiation, and hepatocellular carcinomas were studied. BCL10 immunoreactivity paralleled that of CEH and was restricted to acinar cells of normal and ectopic pancreas, of pancreatic metaplasia, and of ACCs. The anti-BCL10 antibody was more sensitive in detecting ACCs and pancreatic metaplasia than antibodies directed against other pancreatic enzymes. We suggest using BCL10 antibody for diagnosing pancreatic tumors and whenever an acinar differentiation is suspected in gastrointestinal neoplastic and metaplastic lesions.

We report a case of tumour in the head of the pancreas observed in a 57-year-old man with a history of worsening jaundice and elevated alpha-fetoprotein (AFP) serum level, who underwent Whipple pancreatoduodenectomy. Histologically, the tumour was predominantly composed of solid sheets of large eosinophilic cells with a prominent lymphoid infiltration without association neither with DNA microsatellite instability nor Epstein-Barr virus infection. The tumour was diffusely and strongly positive for hepatocyte paraffin-1 (Hep Par-1) and glypican-3 leading to the diagnosis of hepatoid carcinoma. Strong cytoplasmic staining for AFP was focally observed. Moreover, tumour cells showed countless cytoplasmic eosinophilic globules immunoreactive for the stress protein p62. A primary hepatocellular carcinoma of the liver was ruled out by careful clinical analysis. Hepatoid carcinoma is an extremely rare pancreatic neoplasm, and here, we describe the first case of such variant associated with lymphoid stroma. The characteristic histologic features and the immunophenotypic profile help in distinguishing this carcinoma from other pancreatic tumours, notably from medullary carcinoma. [ABSTRACT FROM AUTHOR]

The gastroenteropancreatic (GEP) system is the site of origin of about two thirds of all neuroendocrine neoplasms (NENs) of the human body. GEP-NENs encompass a wide spectrum of entities, from very indolent tumors to highly aggressive carcinomas. They represent a challenge for the oncologist and a correct diagnostic approach is crucial for the management of patients. The nomenclature and classification of these tumors have been a matter of debate for more than a century, since their first description by Siegfried Oberdorfer. The last WHO classification provided a robust and easy-to-use tool to prognostically stratify GEP-NENs, based on morphological aspects and on proliferation rate. This review examines current approaches to the diagnosis and prognostic classification of GEP-NENs, focusing on the critical use of morphological parameters and immunohistochemical stainings, including diagnostic, site-specific and prognostic markers. The key issues of the current classification are addressed, including the emerging topics about cases with discordant morphology and proliferative index. Finally, we attempted to highlight the diagnostic pitfalls and the caveats in the use of immunohistochemical stains. [ABSTRACT FROM AUTHOR]

Erratic regulation of glucose metabolism including hyperglycemia is a common condition in premature infants and is associated with increased morbidity and mortality. The objective of this study was to examine histological and ultrastructural differences in the endocrine pancreas in fetal (throughout gestation) and neonatal baboons. Twelve fetal baboons were delivered at 125 days (d) gestational age (GA), 140d GA, or 175d GA. Eight animals were delivered at term (185d GA); half were fed for 5 days. Seventy-three nondiabetic adult baboons were used for comparison. Pancreatic tissue was studied using light microscopy, confocal imaging, and electron microscopy. The fetal and neonatal endocrine pancreas islet architecture became more organized as GA advanced. The percent areas of &agr;-&bgr;-&dgr;-cell type were similar within each fetal and newborn GA (NS) but were higher than the adults (P<0.05) regardless of GA. The ratio of b cells within the islet (whole and core) increased with gestation (P<0.01). Neonatal baboons, which survived for 5 days (feeding), had a 2.5-fold increase in pancreas weight compared with their counterparts killed at birth (P=0.01). Endocrine cells were also found in exocrine ductal and acinar cells in 125, 140 and 175dGAfetuses. Subpopulation of tissue that coexpressed trypsin and glucagon/ insulin shows the presence of cellswithmixed endo-exocrine lineage in fetuses. In summary, the fetal endocrine pancreas has no prevalence of a &agr;-&bgr;-&dgr;-cell type with larger endocrine cell percent areas than adults. Cells with mixed endocrine/exocrine phenotype occur during fetal development. Developmental differences may play a role in glucose homeostasis during the neonatal period and may have long-term implications. [ABSTRACT FROM AUTHOR]

Summary: Currently used histopathologic criteria for the diagnosis of pancreatic endocrine tumors are still under discussion as far as to their capacity to identify prognostically different tumor subsets, which are potentially helpful for patient management. A recently developed TNM staging system and a variety of proposed histologic and clinicopathologic parameters still need to be fully validated. One hundred fifty-five pancreatic endocrine tumors encompassing all the main histologic types and stages, operated with intention to cure and then followed up for a median 126 months, were carefully investigated histologically to identify prognostically informative parameters at univariable, bivariable, and multivariable analysis. Ki67 index, mitotic rate, neuroinvasion with or without vascular, peritumoral or stromal infiltrative patterns, as well as tumor size, and association with endocrine syndromes other than insulinoma proved effective in predicting recurrence and disease-specific death among well-differentiated tumors. Poorly differentiated histologic features, more than 10 mitoses/10 high power fields, and necrosis were helpful in the identification of high-grade cancers with an invariably poor prognosis. The TNM system proved to be highly predictive of patient outcome and easy to combine with histologic and clinicopathologic parameters to classify pancreatic endocrine tumors into groups of increasing malignant potential. [Copyright &y& Elsevier]

BACE2 is a protease homologous to BACE1 protein, an enzyme involved in the amyloid formation of Alzheimer disease (AD). However, despite the high homology between these two proteins, the biological role of BACE2 is still controversial, even though a few studies have suggested a pathogenetic role in sporadic inclusion-body myositis and hereditary inclusion-body myopathy, which are characterized by vacuolization of muscular fibers with intracellular deposits of proteins similar to those found in the brain of AD patients. Although BACE2 has also been identified in the pancreas, its function remains unknown and its specific localization in different pancreatic cell types has not been definitively ascertained. For these reasons, the authors have investigated the cellular and subcellular localization of BACE2 in normal rodent pancreases. BACE2 immunoreactivity was found in secretory granules of β cells, co-stored with insulin and IAPP, while it was lacking in the other endocrine and exocrine cell types. The presence of BACE2 in secretory granules of β cells suggests that it may play a role in diabetes-associated amyloidogenesis. [ABSTRACT FROM AUTHOR]

Hepatocyte growth factor (HGF), a stimulator of angiogenesis and cell migration, regulates the growth of a wide variety of cells by binding to its high-affinity receptor met and is involved in the growth and aggressiveness of several tumors. In this study we investigated the expression of HGF and met in normal endocrine cells and related neoplasms of the gut and pancreas to verify their possible role in tumor pathogenesis, growth, and aggressiveness. Normal tissues and 60 different endocrine tumors were immunostained using specific antibodies directed against HGF, met, and various hormones. HGF immunoreactivity (IR) was found in antroduodenal G cells, rectal enterochromaffin (EC) cells, and pancreatic A and B cells, whereas met IR was detected in antral EC and G cells, and in pancreatic B cells; 46 of 60 tumors examined were positive for HGF, and they were mainly represented by ECL-, EC-, and L-cell neoplasms. met IR was identified in 50/60 tumors of various phenotypes. HGF and met coexpression was found in 42/60 cases, most of which were represented by EC-cell tumors. HGF/met coexpression was significantly more frequent in ileolonic EC-cell tumors, which in the majority of cases were malignant, than in appendiceal EC-cell tumors, which were all benign. Our results demonstrated, for the first time, that HGF and met are specifically distributed in normal gut and pancreatic endocrine cells and, in addition, suggest that HGF and met may be implicated as autocrine/paracrine factors regulating the growth of gastroenteropancreatic endocrine tumors, mainly of ileocolonic EC-cell carcinoids. [ABSTRACT FROM AUTHOR]

Simple Summary: Ki67-based grading is a major prognostic parameter for pancreatic neuroendocrine tumors. Gene expression profiles of these tumors have been explored, yet their relationship with Ki67-based tumor grade has only been superficially investigated. To fill this gap, we analyzed differentially expressed genes across 29 cases of different grades. Our data provided the first proof that the switch from lower to higher grades is associated with a profound change in the transcriptome. The comparison of multiple samples from the same patients, including primaries and metastasis, showed that the major determinant of difference was tumor grade, irrespective of the anatomic location or patient of origin. These data call for further investigation of this association and of the role of Ki67 in affecting chromosomal stability in neuroendocrine tumors of different grades, which may clarify the basis of tumor progression and provide clues on how to interfere with it. Pancreatic neuroendocrine tumors (PanNETs) display variable aggressive behavior. A major predictor of survival is tumor grade based on the Ki67 proliferation index. As information on transcriptomic profiles of PanNETs with different tumor grades is limited, we investigated 29 PanNETs (17 G1, 7 G2, 5 G3) for their expression profiles, mutations in 16 PanNET relevant genes and LINE-1 DNA methylation profiles. A total of 3050 genes were differentially expressed between tumors with different grades (p < 0.05): 1279 in G3 vs. G2; 2757 in G3 vs. G1; and 203 in G2 vs. G1. Mutational analysis showed 57 alterations in 11 genes, the most frequent being MEN1 (18/29), DAXX (7/29), ATRX (6/29) and MUTYH (5/29). The presence and type of mutations did not correlate with the specific expression profiles associated with different grades. LINE-1 showed significantly lower methylation in G2/G3 versus G1 tumors (p = 0.007). The expression profiles of matched primaries and metastasis (nodal, hepatic and colorectal wall) of three cases confirmed the role of Ki67 in defining specific expression profiles, which clustered according to tumor grades, independently from anatomic location or patient of origin. Such data call for future exploration of the role of Ki67 in tumor progression, given its involvement in chromosomal stability. [ABSTRACT FROM AUTHOR]