Mucosal colonization of gastric endocrine tumors mimicking mixed neoplasms

Two cases of gastric tumors showing mixed composition of endocrine cell clusters and exocrine glands and originally diagnosed as mixed neoplasms are described. In both cases, the exocrine glandular component was restricted to the upper third of the neoplasms being consistently absent in areas of muscular wall invasion and, in case 2, in nodal metastases. These glands were in close anatomical contiguity with the glands of the overlying gastric mucosa or, in case 1, apparently derived from deep pouch-like invaginations of the mucosa. They showed either lack of dysplasia (case 1) or mild dysplasia (case 2) with a Ki67 proliferation index consistently lower than that of the intramucosal glands. The intratumoral glands presented intestinal metaplastic features confirmed by intense Cdx2 immunostaining that, conversely, was absent in the endocrine component of the tumors. The latter showed intense vesicular monoamine transporter 2 immunoreactivity consistent with its origin from the enterochromaffin-like cells of the gastric oxyntic mucosa. On the basis of these findings, it is proposed that the exocrine glands do not represent a true neoplastic component of the tumors. Although mucosal entrapment by the tumor cannot be ruled out, they more likely reflect a hitherto unrecognized mechanism of mucosal colonization of gastric endocrine tumors

Dataset for histopathological reporting of neuroendocrine neoplasms of the gastroenteropancreatic tract

The cancer datasets published by the Royal College of Pathologists (RCPath) are a combination of textual guidance, educational information and reporting proformas. The datasets enable pathologists to grade and stage cancers in an accurate, consistent manner in compliance with international standards and provide prognostic information, thereby allowing clinicians to provide a high standard of care for patients and appropriate management for specific clinical circumstances. This guideline has been developed to cover most common circumstances. However, we recognise that guidelines cannot anticipate every pathological specimen type and clinical scenario. Occasional variation from the practice recommended in this guideline may therefore be required to report a specimen in a way that maximises benefit to the patient

High-Grade Gastroenteropancreatic Neuroendocrine Neoplasms and Improved Prognostic Stratification With the New World Health Organization 2019 Classification A Validation Study From a Single-Institution Retrospective Analysis

Objectives: There is a pressing need to develop clinical management pathways for grade 3 (G3) gastroenteropancreatic neuroendocrine neoplasms (GEP NEN). Methods: We performed a retrospective study on patients with metastatic G3 GEP NEN. The relationship between baseline characteristics and progression-free survival and overall survival was analyzed using the Kaplan-Meier method. Univariate and multivariate analyses were performed using the Cox proportional hazards model. Results: We included 142 patients (74 well-differentiated neuroendocrine tumors [WDNETs], 68 poorly differentiated neuroendocrine carcinomas [PDNECs]). Patients with WDNET had prolonged survival compared with PDNEC (median, 24 vs 15 months, P = 0.0001), which persisted in both pancreatic and nonpancreatic cohorts. Well-differentiated morphology, Ki-67 <50% and positive somatostatin receptor imaging were independently associated with prolonged survival. Of the subgroup treated with first-line platinum-based chemotherapy, response rates were favorable (partial response, 47%; stable disease, 30%); there was no significant difference in response rates nor progression-free survival between WDNET and PDNEC despite significantly prolonged overall survival in the WDNET cohort. Conclusions: Our study corroborates the knowledge of 2 prognostically distinct subgroups within the World Health Organization 2019 G3 GEP NEN population, observed in both pancreatic and nonpancreatic gastrointestinal cohorts. Definitive management pathways are needed to reflect the differences between G3 WDNET and PDNEC

Systematic Evaluation of the Immune Environment of Small Intestinal Neuroendocrine Tumours

BACKGROUND: The immune tumour microenvironment and the potential therapeutic opportunities for immunotherapy in small intestinal neuroendocrine tumours (siNET) have not been fully defined. METHODS: Herein, we studied 40 patients with primary and synchronous metastatic siNETs , and matched blood and normal tissue obtained during surgery. We interrogated the immune checkpoint landscape using multi-parametric flow cytometry. Additionally, matched FFPE tissue was obtained for multi-parametric immunohistochemistry (IHC) to determine the relative abundance and distribution of T-cell infiltrate. Tumour mutational burden (TMB) was also assessed and correlated with immune infiltration. RESULTS: Effector tumour infiltrating lymphocytes had a higher expression of PD-1 in the tumour microenvironment compared to the periphery. Additionally, CD8+ tumour infiltrating lymphocytes had a significantly higher co-expression of PD-1/ICOS and PD-1/CTLA-4 and higher levels of PD-1 expression compared to normal tissue. IHC revealed that the majority of cases have {less than or equal to}10% intratumoural T cells but a higher number of peritumoural T cells, demonstrating an "exclusion" phenotype. Finally, we confirmed that siNETs have a low TMB compared to other tumour types in the TCGA database but did not find a correlation between TMB and CD8/Treg ratio. CONCLUSIONS: Taken together, these results suggest that a combination therapy approach will be required to enhance the immune response, using PD-1 as a checkpoint immunomodulator backbone in combination with other checkpoint targeting molecules (CTLA-4 or ICOS), or with drugs targeting other pathways to recruit "excluded" T cells into the tumour microenvironment to treat patients with siNETs

Exogenous Liposomal ceramide-c6 ammeliorates lipidomic profile, energy homeostasis and anti-oxidant systems in NASH

In non-alcoholic steatohepatitis (NASH), many lines of investigation have reported a dysregulation in lipid homeostasis, leading to intrahepatic lipid accumulation. Recently, the role of dysfunctional sphingolipid metabolism has also been proposed. Human and animal models of NASH have been associated with elevated levels of long chain ceramides and pro-apoptotic sphingolipid metabolites, implicated in regulating fatty acid oxidation and inflammation. Importantly, inhibition of de novo ceramide biosynthesis or knock-down of ceramide synthases reverse some of the pathology of NASH. In contrast, cell permeable, short chain ceramides have shown anti-inflammatory actions in multiple models of inflammatory disease. Here, we investigated non-apoptotic doses of a liposome containing short chain C6-Ceramide (Lip-C6) administered to human hepatic stellate cells (hHSC), a key effector of hepatic fibrogenesis, and an animal model characterized by inflammation and elevated liver fat content. On the basis of the results from unbiased liver transcriptomic studies from non-alcoholic fatty liver disease patients, we chose to focus on adenosine monophosphate activated kinase (AMPK) and nuclear factor-erythroid 2-related factor (Nrf2) signaling pathways, which showed an abnormal profile. Lip-C6 administration inhibited hHSC proliferation while improving anti-oxidant protection and energy homeostasis, as indicated by upregulation of Nrf2, activation of AMPK and an increase in ATP. To confirm these in vitro data, we investigated the effect of a single tail-vein injection of Lip-C6 in the methionine-choline deficient (MCD) diet mouse model. Lip-C6, but not control liposomes, upregulated phospho-AMPK, without inducing liver toxicity, apoptosis, or exacerbating inflammatory signaling pathways. Alluding to mechanism, mass spectrometry lipidomics showed that Lip-C6-treatment reversed the imbalance in hepatic phosphatidylcholines and diacylglycerides species induced by the MCD-fed diet. These results reveal that short-term Lip-C6 administration reverses energy/metabolic depletion and increases protective anti-oxidant signaling pathways, possibly by restoring homeostatic lipid function in a model of liver inflammation with fat accumulation

Impaired LXRa phosphorylation attenuates progression of fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) is a very common indication for liver transplantation. How fat-rich diets promote progression from fatty liver to more damaging inflammatory and fibrotic stages is poorly understood. Here, we show that disrupting phosphorylation at Ser196 (S196A) in the liver X receptor alpha (LXRα, NR1H3) retards NAFLD progression in mice on a high-fat-high-cholesterol diet. Mechanistically, this is explained by key histone acetylation (H3K27) and transcriptional changes in pro-fibrotic and pro-inflammatory genes. Furthermore, S196A-LXRα expression reveals the regulation of novel diet-specific LXRα-responsive genes, including the induction of Ces1f, implicated in the breakdown of hepatic lipids. This involves induced H3K27 acetylation and altered LXR and TBLR1 cofactor occupancy at the Ces1f gene in S196A fatty livers. Overall, impaired Ser196-LXRα phosphorylation acts as a novel nutritional molecular sensor that profoundly alters the hepatic H3K27 acetylome and transcriptome during NAFLD progression placing LXRα phosphorylation as an alternative anti-inflammatory or anti-fibrotic therapeutic target

Gastric Mixed Adenoneuroendocrine Carcinoma with a Trilineage Cell Differentiation: Case Report and Review of the Literature

Most gastric neuroendocrine tumours are well differentiated and considered as neuroendocrine neoplasms, whilst poorly differentiated lesions are considered as neuroendocrine carcinomas and account for only 6–16% of gastric neuroendocrine tumours. Gastric mixed adenoneuroendocrine carcinomas are rare malignancies usually composed of a neuroendocrine carcinoma and an adenocarcinoma with a variable grade of differentiation. Here, we report an unusual and rare gastric mixed adenoneuroendocrine carcinoma with a trilineage cell differentiation including a neuroendocrine carcinoma, an adenocarcinoma and a squamous cell carcinoma. A brief discussion of the histopathological features, biological behaviour and treatment of this rare tumour type is presented