Increased SLC38A4 Amino Acid Transporter Expression in Human Pancreatic α-Cells After Glucagon Receptor Inhibition.

Plasma amino acids and their transporters constitute an important part of the feedback loop between the liver and pancreatic α-cell function, and glucagon regulates hepatic amino acid turnover. Disruption of hepatic glucagon receptor action activates the loop and results in high plasma amino acids and hypersecretion of glucagon associated with α-cell hyperplasia. In the present study, we report a technique to rescue implanted human pancreatic islets from the mouse kidney capsule. Using this model, we have demonstrated that expression of the amino acid transporter SLC38A4 increases in α-cells after administration of a glucagon receptor blocking antibody. The increase in SLC38A4 expression and associated α-cell proliferation was dependent on mechanistic target of rapamycin pathway. We confirmed increased α-cell proliferation and expression of SLC38A4 in pancreas sections from patients with glucagon cell hyperplasia and neoplasia (GCHN) with loss-of-function mutations in the glucagon receptor. Collectively, using a technique to rescue implanted human islets from the kidney capsule in mice and pancreas sections from patients with GCHN, we found that expression of SLC38A4 was increased under conditions of disrupted glucagon receptor signaling. These data provide support for the existence of a liver-human α-cell endocrine feedback loop.

Colorectal Neuroendocrine Neoplasms: Areas of Unmet Need.

The subject of colorectal neuroendocrine neoplasms (NENs), subdivided into well-differentiated NENs, termed neuroendocrine tumours (NETs; grade (G) 1 and 2), and poorly differentiated NENs, termed neuroendocrine carcinomas (NECs; G3) according to the 2010 World Health Organisation (WHO) classification, has arguably not had as much attention or study as NENs occurring in other sites. Colorectal NETs and NECs are however easier to study than many others since they are usually not difficult to remove and are increasingly detected because of intensified colorectal cancer screening and surveillance programmes. Colorectal NETs and NECs show site-specific heterogeneity with variable behaviour and different therapeutic options; these various aspects provide unique challenges. Because of bowel cancer screening programmes, colorectal NENs, like conventional adenocarcinomas, may be diagnosed at a stage that is associated with improved survival. In this article we intend to describe and define areas of unmet needs relating to the epidemiology, classification, pathology, diagnosis and therapy of colorectal NETs (including NETs G3), colorectal NECs, and finally, mixed adeno-neuroendocrine carcinomas (MANECs) by reviewing and discussing the relevant literature.

Clinical profile of autoimmune pancreatitis and its histological subtypes: an international multicenter survey.

OBJECTIVE: The objective of this study was to clarify the clinical and pathophysiological characteristics of autoimmune pancreatitis (AIP) and its subtypes (lymphoplasmacytic sclerosing pancreatitis [LPSP] and idiopathic duct-centric pancreatitis [IDCP]) seen around the world. METHODS: An international multicenter survey of AIP was conducted in 15 institutes from 8 countries. We compared clinical and pathologic profiles of AIP (n = 731) and the clinical profiles of LPSP (n = 204) and IDCP (n = 64) patients. RESULTS: Patients with LPSP were approximately 16 years older than IDCP patients. Obstructive jaundice was a more frequent presentation in LPSP versus IDCP (75% vs 47%, P < 0.001), whereas abdominal pain (41% vs 68%, P < 0.001) and acute pancreatitis (5% vs 34%, P < 0.001) were more frequent in IDCP patients. Patients with LPSP were more likely to have diffuse swelling of the pancreas (40% vs 25%, P = 0.037) and elevated serum IgG4 levels (63% vs 23%, P < 0.001) but less likely to be associated with ulcerative colitis (1% vs 16%, P < 0.001). Clinical profiles of non-histologically confirmed AIP from Asia, the United States, and United Kingdom corresponded with that of LPSP, whereas those from Italy and Germany suggested a mixture of LPSP and IDCP. CONCLUSIONS: Autoimmune pancreatitis is seen all around the world, with regional differences in the pathologic and clinical features. Lymphoplasmacytic sclerosing pancreatitis and IDCP have distinct clinical profiles.

Histopathologic and clinical subtypes of autoimmune pancreatitis: the Honolulu consensus document.

Autoimmune pancreatitis (AIP) has been extensively reported from Japan, Europe, and the United States. Whereas the descriptions of AIP from Japan have predominantly been based on the presence of a distinct clinical phenotype, reports from Europe and the United States describe at least 2 histopathologic patterns in patients' condition currently diagnosed as AIP, viz, lymphoplasmacytic sclerosing pancreatitis (LPSP) and idiopathic duct centric pancreatitis (IDCP) or granulocyte epithelial lesion (GEL)-positive pancreatitis. Although the 2 entities share common histopathologic features (periductal lymphoplasmacytic infiltration and peculiar periductal fibrosis), expert pathologists can accurately distinguish them based on other unique histopathologic features. Clinically, the 2 entities have similar clinical presentation (obstructive jaundice/pancreatic mass and a dramatic response to steroids) but differ significantly in their demography, serological characteristics, other organ involvement, and disease relapse. While LPSP is associated with elevation in titers of nonspecific autoantibodies and serum IgG4 levels, IDCP does not have definitive serological autoimmune markers. All experts agreed that the clinical phenotypes associated with LPSP and IDCP should be nosologically distinguished; however, their terminology was debated. Whereas most experts agreed that the entities should be referred to as type 1 and type 2 AIP, respectively, others had concerns regarding use of the term "autoimmune" to describe IDCP.

Histopathologic and clinical subtypes of autoimmune pancreatitis: the honolulu consensus document.

Autoimmune pancreatitis (AIP) has been extensively reported from Japan, Europe and the USA. While the descriptions of AIP from Japan have predominantly been based on the presence of a distinct clinical phenotype, reports from Europe and the USA describe at least 2 histopathologic patterns in patients diagnosed with AIP, namely lymphoplasmacytic sclerosing pancreatitis (LPSP) and idiopathic duct-centric pancreatitis (IDCP) or granulocytic epithelial lesion- positive pancreatitis. While the 2 entities share common histopathologic features (periductal lymphoplasmacytic infiltration and peculiar periductal fibrosis), expert pathologists can accurately distinguish them on the basis of other unique histopathologic features. Clinically, the 2 entities have a similar presentation (obstructive jaundice/pancreatic mass and a dramatic response to steroids), but they differ significantly in their demography, serology, involvement of other organs and disease relapse rate. While LPSP is associated with elevation of titers of nonspecific autoantibodies and serum IgG4 levels, IDCP does not have definitive serologic autoimmune markers. All experts agreed that the clinical phenotypes associated with LPSP and IDCP should be nosologically distinguished; however, their terminology was controversial. While most experts agreed that the entities should be referred to as type 1 and type 2 AIP, respectively, others had concerns regarding use of the term 'autoimmune' to describe IDCP. and IAP.

The German NET-registry: an audit on the diagnosis and therapy of neuroendocrine tumors.

AIMS: Clinical experience with neuroendocrine tumors (NETs) is difficult to acquire because they are rare and heterogeneous. The impact of guidelines on the care for NETs is not known. The German NET Registry compiled information for Germany pertaining to three questions: who provides care for NET patients; does the care comply with proposed guidelines, and are the results comparable to those described in the literature? PATIENTS AND METHODS: Between 2004 and 2007 data on 1,263 patients from 21 centers were compiled in a dedicated database. RESULTS: Tumor location, age and sex compared well with published data. Most patients were cared for in centers with more than 100 (47.9%) or between 20 and 99 patients (46.1%). Imaging (magnetic resonance tomography, computer tomography, ultrasound) was available for 79% of the patients, specific laboratory tests for 67%, somatostatin receptor scintigraphy for 56%, and pathology findings for 79%. High-quality pathology reports were rare (2%). Sufficient documentation was mostly found in large centers. Surgery was the first-line therapy in 70.9%, while medical therapy was the second-line therapy in 45.7% of the patients. Median follow-up was 2.8 (0.4-6.4) and median overall survival was 2.5 (0.34-6.3) years. CONCLUSIONS: Most patients were referred to large specialized centers. Those centers adhered best to published guidelines for NETs. However, there are still significant deficiencies in the documentation of diagnostic results, mainly with regard to pathology reports. Therapeutic strategies were comparable between centers. The data provide a basis for future studies assessing improvements in documentation, diagnosis and treatment of NET.

Histopathologic features and microsatellite instability of cancers of the papilla of vater and their precursor lesions.

The prevalence and development of microsatellite instability (MSI) and underlying mismatch repair (MMR) deficiency in the carcinogenesis of adenocarcinomas of the papilla of Vater and their precursor lesions are not well established. We analyzed 120 ampullary adenomas (31 pure adenomas and 89 carcinoma-associated adenomas) and 170 pure adenocarcinomas for MSI, immunohistochemical expression of MMR proteins and specific histopathologic features. The most common histologic subtype was intestinal (46.5%), followed by pancreatobiliary (23.5%), poorly differentiated adenocarcinomas (12.9%), intestinal-mucinous (8.2%), and invasive papillary carcinomas (5.3%). Eight of 89 adenomas (9%) and 15/144 carcinomas (10%) showed high microsatellite instability (MSI-H), 10/89 adenomas (11%) and 5/144 carcinomas (4%) showed low microsatellite instability (MSI-L), and 71/89 adenomas (80%) and 124/144 carcinomas (86%) were microsatellite stable (MSS). MSI analysis from carcinomas contiguous with an adenomatous component (n=54) exhibited concordant results in 6/8 (75%) MSI-H and 42/46 (91.3%) MSS tumors. Of 14 carcinomas with MSI-H, 7 showed loss of MLH1 and 5/6 (83%) MLH1 promoter methylation, and 2 carcinomas showed simultaneous loss of MSH2 and MSH6. Two carcinomas and 3 adenomas with MSI-H revealed exclusive loss of MSH6. MSI-H cancers were significantly associated with intestinal mucinous subtype (P<0.001), high tumor grade (P=0.003), expansive growth pattern (P=0.044), and marked lymphoid host response (P=0.004). Patients with MSI-H carcinoma had a significantly longer overall survival (P=0.0082) than those with MSI-L or MSS tumors. Our findings indicate that the MSI-phenotype is an early event, which develops at the stage of adenoma and is reliably detectable in the precursor lesion. The MMR deficient molecular pathway of carcinogenesis is associated with a histopathologic phenotype in ampullary cancer, similar to the one that has been well described in colon cancer.

WHO 2004 criteria and CK19 are reliable prognostic markers in pancreatic endocrine tumors.

BACKGROUND: It is difficult to predict the biologic behavior of pancreatic endocrine tumors in absence of metastases or invasion into adjacent organs. The World Health Organization (WHO) has proposed in 2004 size, angioinvasion, mitotic activity, and MIB1 proliferation index as prognostic criteria. Our aim was to test retrospectively the predictive value of these 2004 WHO criteria and of CK19, CD99, COX2, and p27 immunohistochemistry in a large series of patients with long-term follow-up. DESIGN: The histology of 216 pancreatic endocrine tumor specimens was reviewed and the tumors were reclassified according to the 2004 WHO classification. The prognostic value of the WHO classification and the histopathologic criteria necrosis and nodular fibrosis was tested in 113 patients. A tissue microarray was constructed for immunohistochemical staining. The staining results were scored quantitatively for MIB1 and semiquantitatively for CK19, COX2, p27, and CD99. The prognostic value of these markers was tested in 93 patients. RESULTS: The stratification of the patients into 4 risk groups according to the 2004 WHO classification was reliable with regard to both time span to relapse and tumor-specific death. In a multivariate analysis, the CK19 status was shown to be independent of the WHO criteria. By contrast, the prognostic significance of COX2, p27, and CD99 could not be confirmed. CONCLUSIONS: The 2004 WHO classification with 4 risk groups is very reliable for predicting both disease-free survival and the time span until tumor-specific death. CK19 staining is a potential additional prognostic marker independent from the WHO criteria for pancreatic endocrine tumors.