Site-specific biology and pathology of gastroenteropancreatic neuroendocrine tumors

Gallbladder Neuroendocrine Neoplasms in Dogs and Humans

Gallbladder neuroendocrine neoplasms (GB NENs) are among the rarest cancers reported in humans and dogs. This review provides a detailed review of the canine GB NEN literature and an interspecies comparison of demographics, clinical pathophysiology, pathobiology, and therapeutic response of GB NENs. The aim of this work is to explore the relevance of dogs as a spontaneous model for human GB NENs.

Evaluation of immunohistochemical expression of novel neuroendocrine marker INSM1 and histological tumor growth pattern in well-differentiated neuroendocrine tumors of the appendix: 15-year single tertiary center experience

INTRODUCTION

Well-differentiated neuroendocrine tumors of the appendix (A-WDNET) are the most common neoplasms of the appendix but are rare and incidental. INSM1 is a novel transcription factor marker with high sensitivity and specificity for neuroendocrine differentiation. It may display architecturally diverse tumor growth patterns including solid, nest, insular trabecular, and acinar.

AIMS

The aim of this study was to determine the staining expression of INSM1 in A-WDNETs and detail the morphological tumor growth patterns.

MATERIALS AND METHODS

INSM1 immunohistochemistry was performed on 35 A-WDNET patients. Tumors were histologically classified according to their growth patterns.

RESULTS

Thirty-five patients, 60% of whom were male, had a mean age of 30 years at diagnosis and a mean tumor size of 0.9 cm. Eight percent of the tumors invaded the mucosa/submucosa, 34.3% showed invasion into the muscularis propria, 57.1% showed invasion into the subserosa or mesoappendix, LN metastasis was observed in two patients, lymph-vascular invasion in two patients, and perineural invasion in five patients. Ninety-four percent of the tumors were grade 1, the mitotic rate was >2% in two cases, and Ki-67 PI was >3% in two cases. INSM1 was positive in all cases (100%), 1+ 8.6%, 2+ 5.7%, 3+ 17.1%, 4+ 68.6%, weak staining in 11.4%, moderate staining in 22.9%, and strong staining in 67.7%. Type A histological growth pattern was observed in 54.3%, type B in 31.4%, and type C in 14.3% architecturally.

CONCLUSIONS

INSM1 was positive in all A-WDNET morphological patterns and was 100% sensitive. INSM1 IHC can be used as an alternative to traditional neuroendocrine markers or in combination with the diagnosis of neuroendocrine tumors.

Gastroenteropancreatic Neuroendocrine Tumors-Current Status and Advances in Diagnostic Imaging

Gastroenteropancreatic neuroendocrine neoplasia (GEP-NEN) is a heterogeneous and complex group of tumors that are often difficult to classify due to their heterogeneity and varying locations. As standard radiological methods, ultrasound, computed tomography (CT), magnetic resonance imaging (MRI), and positron emission tomography-computed tomography (PET/CT) are available for both localization and staging of NEN. Nuclear medical imaging methods with somatostatin analogs are of great importance since radioactively labeled receptor ligands make tumors visible with high sensitivity. CT and MRI have high detection rates for GEP-NEN and have been further improved by developments such as diffusion-weighted imaging. However, nuclear medical imaging methods are superior in detection, especially in gastrointestinal NEN. It is important for radiologists to be familiar with NEN, as it can occur ubiquitously in the abdomen and should be identified as such. Since GEP-NEN is predominantly hypervascularized, a biphasic examination technique is mandatory for contrast-enhanced cross-sectional imaging. PET/CT with somatostatin analogs should be used as the subsequent method.

Genetics of Pancreatic Neuroendocrine Tumors

Pancreatic neuroendocrine tumors (pNETs) represent a relatively rare disease; however, the incidence has been increasing during the last 2 decades. Next generation sequencing has greatly increased our understanding of driver mutations in pNETs. Sporadic pNETs have consistently presented with mutations in MEN1, DAXX/ATRX, and genes related to the mammalian target of rapamycin pathway. Inherited pNETs have traditionally been associated with multiple endocrine neoplasia type 1, von Hippel-Lindau syndrome, neurofibromatosis type 1, and tuberous sclerosis complex. The current review expands on the existing knowledge and the relevant updates on the genetics of pNETs.

New Developments in Gastric Neuroendocrine Neoplasms

Purpose of Review

Gastric neuroendocrine neoplasms (g-NENs) are a rare type of stomach cancer. The three main subtypes have different pathogeneses, biological behaviours and clinical characteristics, so they require different management strategies. This article will provide an overview of g-NENs and highlight recent advances in the field.

Recent Findings

Molecular profiling has revealed differences between indolent and aggressive g-NENs, as well as a new somatic mutation responsible for some familial type I g-NENs. Novel biomarkers have been developed which will hopefully improve diagnosis, treatment, risk stratification and follow-up. Patient treatment is also changing, as evidence supports the use of less aggressive options (e.g. endoscopic surveillance or resection) in some patients with more indolent tumours.

Summary

g-NEN heterogeneity poses challenges in understanding and managing this rare disease. More basic science research is needed to investigate molecular pathogenesis, and future larger clinical studies will hopefully also further improve treatment and patient outcomes.

Clinicopathologic Characteristics of Gastroenteropancreatic Neuroendocrine Tumors: Experience of a National Referral Hospital in Indonesia

Gastroenteropancreatic neuroendocrine tumors (GEP-NETs) have variable biological behavior although they are all malignant. This study presents the 10-year prevalence along with the clinicopathologic characteristics of GEP-NETs and their association with tumor grade at a national referral hospital in Indonesia. This is a retrospective cross-sectional study of patients with GEP-NET confirmed by histomorphology and immunohistochemistry who presented to Cipto Mangunkusumo Hospital from 2009 to 2019. Clinical characteristics included age, sex, primary site, tumor stage, metastasis, hormone status, and chief complaints. Pathological characteristics included the type of GEP-NET, specimen type, grade, and presence of lymphovascular invasion (LVI). Statistical analysis was performed to determine the association between characteristics and tumor grade. A total of 84 cases of GEP-NET from 2009 to 2019 were included; of these, 38.1% were neuroendocrine tumors (NETs), 28.6% were neuroendocrine carcinomas (NECs), and 33.3% were mixed neuroendocrine-non-neuroendocrine neoplasm (MiNEN). The mean patient age was 48.36 years, and the male to female ratio was 1. GEP-NETs predominantly originated from the rectum (21.4%) and were mostly non-functioning (90.5%) with an average tumor size of 4.77 cm. Most tumors were localized (53.6%), but metastasis was found in 28.6% cases. LVI was positive in 35.7% cases. High-grade tumors were more common (54.3%) than low-grade tumors. High-grade tumors were associated with unknown primary sites, dissemination, LVI, and larger tumor size. To conclude, GEP-NETs can arise from any site in the gastrointestinal tract and have variable clinicopathologic characteristics. Primary site, stage, LVI, and tumor size are associated with grade.

Pituitary neuroendocrine tumors: a model for neuroendocrine tumor classification

The classification of adenohypophysial neoplasms as "pituitary neuroendocrine tumors" (PitNETs) was proposed in 2017 to reflect their characteristics as epithelial neuroendocrine neoplasms with a spectrum of clinical behaviors ranging from small indolent lesions to large, locally invasive, unresectable tumors. Tumor growth and hormone hypersecretion cause significant morbidity and mortality in a subset of patients. The proposal was endorsed by a WHO working group that sought to provide a unified approach to neuroendocrine neoplasia in all body sites. We review the features that are characteristic of neuroendocrine cells, the epidemiology and prognosis of these tumors, as well as further refinements in terms used for other pituitary tumors to ensure consistency with the WHO framework. The intense study of PitNETs has provided information about the importance of cellular differentiation in tumor prognosis as a model for neuroendocrine tumors in different locations.

Mixed adenoneuroendocrine carcinomas of stomach and ampulla of vater after curative-intent resection: a single center cases series

Background

Mixed adenoneuroendocrine carcinoma is a rare clinical manifestation, especially in the gastric and ampullary. The purpose of this study was to investigate the clinicopathological features and prognosis of mixed adenoneuroendocrine carcinoma in the gastric and ampullary and summarize related treatment suggestions.

Methods

In all, 32 cases of mixed adenoneuroendocrine carcinoma in the gastric and ampullary that were diagnosed from resected specimens were analyzed from 2009 to 2015. The corresponding demographic, clinicopathological and survival data were retrospectively reviewed.

Results

The 1-year, 3-year and 5-year survival rates were 78.1%, 28.1 and 9.4%, respectively, and the median overall survival was 28.0 months. In all, 75.0% (24/32) had lymph node metastasis at the time of initial diagnosis. A multivariate analysis revealed that TNM stage (HR 6.444 95%CI 1.477–28.121 P = 0.013), lymph nodes metastasis (HR10.617 95%CI 1.409–79.997 P = 0.022), vascular invasion (HR 5.855 95%CI 1.719–19.940 P = 0.005), grade of the adenocarcinoma component (HR 3.876 95%CI 1.451–10.357 P = 0.007) and CD56 positivity (HR 0.265 95%CI 0.100–0.705 P = 0.008) were independent predictors of overall survival.

Conclusions

Mixed adenoneuroendocrine carcinoma is an aggressive clinical entity with a poor prognosis. Taking both the neuroendocrine component and the adenocarcinoma component into consideration of optimal treatment is strongly recommended.

How to Manage Small Intestine (Jejunal and Ileal) Neuroendocrine Neoplasms Presenting with Liver Metastases?

PURPOSE OF REVIEW

Small intestinal neuroendocrine neoplasms (siNENs) are slowly growing tumours with a low malignant potential. However, more than half of the patients present with distant metastases (stage IV) and nearly all with locoregional lymph node (LN) metastases at the time of surgery. The value of locoregional treatment is discussed controversially.

RECENT FINDINGS

In stage I to III disease, locoregional surgery was currently shown to be curative prolonging survival. In stage IV disease, surgery may prolong survival in selected patients with the chance to cure locoregional disease besides radical/debulking liver surgery. It may improve the quality of life and may prevent severe local complications resulting in a state of chronic malnutrition and severe intestinal ischaemia or bowel obstruction. Locoregional tumour resection offers the opportunity to be curative or to focus therapeutically on liver metastasis, facilitating various other therapeutic modalities. Risks and benefits of the surgical intervention need to be balanced individually.

Advances in Molecular Imaging and Radionuclide Therapy of Neuroendocrine Tumors

Neuroendocrine neoplasms make up a heterogeneous group of tumors with inter-patient and intra-patient variabilities. Molecular imaging can help to identify and characterize neuroendocrine tumors (NETs). Furthermore, imaging and treatment with novel theranostics agents offers a new, tailored approach to managing NETs. Recent advances in the management of NETs aim to enhance the effectiveness of targeted treatment with either modifications of known substances or the development of new substances with better targeting features. There have been several attempts to increase the detectability of NET lesions via positron emission tomography (PET) imaging and improvements in pretreatment planning using dosimetry. Especially notable is PET imaging with the radionuclide Copper-64. Increasing interest is also being paid to theranostics of grade 3 and purely differentiated NETs, for example, via targeting of the C-X-C motif chemokine receptor 4 (CXCR4). The aim of this review is to summarize the most relevant recent studies, which present promising new agents in molecular imaging and therapy for NETs, novel combination therapies and new applications of existing molecular imaging modalities in nuclear medicine.

Modified staging system for gastric neuroendocrine carcinoma based on American Joint Committee on Cancer and European Neuroendocrine Tumor Society systems

BACKGROUND

The prognostic values of the AJCC staging system for gastric cancer (GC-AJCC), the AJCC staging system for gastric neuroendocrine tumours (NET-AJCC) and the European Neuroendocrine Tumor Society (ENETS) system for gastric neuroendocrine carcinoma and mixed adenoneuroendocrine carcinoma (MA)NEC remain controversial.

METHODS

Data on patients with (MA)NEC from 21 centres in China were analysed. Different staging systems were evaluated by performing Kaplan-Meier survival analysis and calculating the concordance index (C-index) and Akaike information criterion (AIC). Based on three existing systems, a modified staging system (mTNM) was developed.

RESULTS

A total of 871 patients were included. In the GC-AJCC system, an overlap was noticed for pT2 and pT3 categories. Patients with stage IIIC disease had a similar prognosis to those with stage IV disease. The pT categories of the NET-AJCC system had a lower C-index and higher AIC than those of the other systems. In the ENETS system, there was a low proportion (0·2 per cent) of patients with stage IIIA and a high proportion (67·6 per cent) of stage IIIB disease. The mTNM system adopted the NET-AJCC pT and GC-AJCC pN and pM definitions, and was developed based on the ENETS stage definitions. The proportion of patients in each stage was better distributed and the mTNM system showed improved prognostic performance in predicting overall and disease-free survival.

CONCLUSION

The mTNM system offers more accurate prognostic value for gastric (MA)NEC than the AJCC or ENETS staging systems.

CD57 as a routine neuroendocrine marker for liver metastasis

Background

The characterization of hepatic metastases as having neuroendocrine origins is essential and the main markers currently used are chromogranin A (CgA) and synaptophysin (Syn). However, these markers may exhibit certain limitations, and the use of CD56 and CD57 can also be considered, although, due to low specificity, their use is discouraged.

Aim

This study sought to compare the immunohistochemical expression of these markers in hepatic metastases of neuroendocrine neoplasms (NEN).

Materials and Methods

Eighteen samples, were used for immunohistochemical staining with CgA, Syn, CD56, and CD57 antibodies. The immunostaining reactions were compared according to its intensity (I), the percentage of labeled cells (P), and a final score (I × P). Statistical agreement between the markers was also evaluated.

Results

CD57 was expressed in the highest number of cases and also showed the most intense expression. CgA showed the highest number of cases with more than 80% positively stained area (72.2%), followed by CD57 (61.1%). The highest average score (I × P) was obtained for CD57 (9.1 ± 4.1). The best indices of agreement were between CgA and CD57 with respect to positivity (P = 0.021) and score (P = 0.014). According to the primary site, stomach/duodenum, lungs, and undetermined subgroups showed the highest average scores for CD57, followed by CgA. For the small bowel subgroup, the highest average score was obtained for CgA, followed by CD57.

Conclusion

Our results highlight the importance of CD57 in the evaluation of hepatic metastases of NEN and indicate that this marker should be included with CgA and Syn in routine diagnostic panels.

Epithelial-Mesenchymal Transition Proteins in Neuroendocrine Neoplasms: Differential Immunohistochemical Expression in Different Sites and Correlation with Clinico-Pathological Features

The first step leading to metastasis, or for the acquisition of local invasiveness, involves changes in the phenotype of neoplastic cells in the primary tumor. The epithelial–mesenchymal transition (EMT) is a process that determines the acquisition of a form and a transcriptional program that are characteristic of mesenchymal cells, in epithelial cells. The factors involved in this process are E-cadherin and N-cadherin adhesion proteins and some transcription factors such as Slug and Twist. EMT is a site-specific mechanism that is also active in embryogenesis—embryonic cells are affected if invested in certain points, probably due to the signals emanating from the cells or groups of surrounding cells. It is known that neuroendocrine neoplasms have a biological behavior that differs in grading, staging, and site. The aim of our study was to investigate the immunohistochemical expression of EMT factors (Twist, Slug, and E-cadherin) in the neuroendocrine neoplasms of the gastrointestinal tract, the pancreas, and lungs, in 65 cases retrieved from the archives of the Department of Pathology, of three hospitals. The immunoscores were compared in each site and correlated with the clinico-pathological parameters. Statistical evaluation revealed an association between the higher Twist immunoscore and higher grading (p value < 0.0001) and staging (p value = 0.0055). Slug was detected only in pancreatic cases where its reduced expression was associated with a higher grading (p value = 0.0033). This data could be of diagnostic utility in the case of metastases from neuroendocrine neoplasm, to define the site of the primitive tumor when the traditional immunohistochemical panel is not sufficient. In summary, our results indicated, first that the EMT is also an active process in neuroendocrine neoplasms. To the best of our knowledge, this was the first study that evaluated the expression of EMT factors in neuroendocrine neoplasms of different districts.

Dual-color immunocytochemistry (Ki-67 with LCA) for precise grading of pancreatic neuroendocrine tumors with applicability to small biopsies and cell blocks

Ki-67 (MIB-1) immunostaining to quantify the proliferative index of neuroendocrine tumors (NETs) has been recommended (especially for small biopsies). However, this has a number of challenges with nonrepresentative Ki-67 index due to interference by Ki-67 immunoreactive proliferating lymphocytes infiltrating the tumor and also some proliferating stromal cells including endothelial cells in the background. Our pilot project showed that dual-color immunostaining with inclusion of leukocyte common antigen (LCA) (Ki-67: nuclear brown; LCA: cytoplasmic red) can facilitate the weeding out of lymphocyte interference. We analyzed the results with 23 surgical cases of pancreatic NETs. This was followed by poststudy examination of 11 cases of endoscopic ultrasound-guided fine-needle aspiration of the pancreatic NETs (PanNETs) to evaluate the findings of the study. Dual-color immunostaining for Ki-67 with LCA increased the precision of quantifying Ki-67 index, due to ability to exclude LCA immunoreactive lymphocytes. Other nontumor Ki-67 immunoreactive cells such as endothelial and stromal cells could be distinguished morphologically. Digital methods were also attempted, but this approach could not distinguish infiltrating lymphocytes and other cells in sections resulting in erroneous results. This study demonstrated that grading of PanNET can be performed with increased precision with dual-color Ki-67 immunostaining protocol standardized in this study. As evaluated on a few cytopathology cases, this protocol is especially useful for the evaluation of small biopsies and cell block sections of fine-needle aspiration biopsy material where 50 high-power fields cannot be evaluated but have >500 tumor cell nuclei.

Do neuroendocrine carcinomas and mixed neuroendocrine-non-neuroendocrine neoplasm of the gastrointestinal tract have the same prognosis? A SEER database analysis of 12,878 cases

BACKGROUND

Neuroendocrine carcinomas (NECs) and mixed neuroendocrine-non-neuroendocrine neoplasm (MiNEN) in the gastrointestinal (GI) tract are both rare and malignant; however, it is unclear whether their prognosis is the same.

METHODS

In this cross-sectional study, a total of 12,878 patients with NEC or MiNEN in the GI tract were reviewed retrospectively by searching the Surveillance, Epidemiology, and End Results (SEER) program database. Next, we compared the characteristics and survival between patients with NEC or MiNEN and further analyzed the prognostic factors for the patients.

RESULTS

The data showed that patients with MiNEN had a worse prognosis as compared with patients with pure NEC in the small intestine (SI) and appendix, whereas there was no significant survival difference between NEC and MiNEN in the other parts of the GI system. On the whole, age ⩾55 years (p < 0.0001), male (p = 0.002), being diagnosed at TNM Stage II-IV (p < 0.0001) or not receiving surgical treatment (p < 0.0001) were the independent negative prognostic factors for NEC patients, whereas age ⩾55 years (p = 0.003), being diagnosed at TNM Stage III-IV (p < 0.001) or not receiving surgical treatment (p < 0.001) were identified as the independent negative prognostic factors for the MiNEN patients. Furthermore, when NECs or MiNENs were classified based on the primary tumor site, the results showed that the prognostic factors for NEC and MiNEN varied between the tumor sites.

CONCLUSION

The prognostic differences between NECs and MiNENs in the GI tract are heterogeneous and site-related. Patients with appendiceal or SI MiNEN have a poorer prognosis than patients with pure appendiceal or SI NEC. Therefore, we should pay more attention to patients with MiNEN in the SI and appendix and monitor them more closely.

Histopathologist-level quantification of Ki-67 immunoexpression in gastroenteropancreatic neuroendocrine tumors using semiautomated method

The role of Ki-67 index in determining the prognosis and management of gastroenteropancreatic neuroendocrine tumors (GEP-NETs) has become more important yet presents a challenging assessment dilemma. Although the precise method of Ki-67 index evaluation has not been standardized, several methods have been proposed, and each has its pros and cons. Our study proposes an imaging semiautomated informatics framework [semiautomated counting (SAC)] using the popular biomedical imaging tool "ImageJ" to quantify Ki-67 index of the GEP-NETs using camera-captured images of tumor hotspots. It aims to assist pathologists in achieving an accurate and rapid interpretation of Ki-67 index and better reproducibility of the results with minimal human interaction and calibration. Twenty cases of resected GEP-NETs with Ki-67 staining that had been done for diagnostic purposes have been randomly selected from the pathology archive. All of these cases were reviewed in a multidisciplinary cancer center between 2012 and 2019. For each case, the Ki-67 immunostained slide was evaluated and five camera-captured images at 40 × magnification were taken. Prints of images were used by three pathologists to manually count the tumor cells. The digital versions of the images were used for the semiautomated cell counting using ImageJ. Statistical analysis of the Ki-67 index correlation between the proposed method and the MC revealed strong agreement on all the cases evaluates ( n = 20 ), with an intraclass correlation coefficient of 0.993, "95% CI: 0.984 to 0.997." The results obtained from the SAC are promising and demonstrate the capability of this methodology for the development of reproducible and accurate semiautomated quantitative pathological assessments. ImageJ features are investigated carefully and accurately fine-tuned to obtain the optimal sequence of steps that will accurately calculate Ki-67 index. SAC is able to accurately grade all the cases evaluated perfectly mating histopathologists' manual grading, providing reliable and efficient solution for Ki-67 index assessment.

Gastrointestinal mixed adenoneuroendocrine carcinoma (MANEC): An immunohistochemistry study of 13 microsatellite stable cases

BACKGROUND

Mixed adenoneuroendocrine carcinoma (MANEC) is currently included in the category of neuroendocrine carcinomas but the therapeutically management is not yet defined.

AIMS

To present the immunohistochemical (IHC) features of the epithelial mesenchymal transition (EMT) of MANEC.

MATERIALS AND METHODS

The clinicopathological features of 13 consecutive cases of MANEC (6 gastric and 7 colorectal) were correlated with the IHC expression of the biomarkers E-cadherin, β-catenin, N-cadherin, vimentin, maspin, CD44 and S100. In all of the cases open surgery was performed.

RESULTS

All of the cases showed microsatellite stable status, expressed E-cadherin and membrane β-catenin in both components (neuroendocrine and adenocarcinoma) and were negative for N-cadherin, vimentin and S-100. The colorectal MANECs were negative for maspin. In gastric MANECs, maspin showed cytoplasm positivity in the neuroendocrine component and nuclear translocation in the adenocarcinoma cells. CD44 was positive in all of the cases, in both components. No tumor buddings were identified. Three of the 13 patients survived for at least 32 months, all of them showing lymphatic emboli but not lymph node metastases. Pure neuroendocrine lymph node metastases were seen in only four of the cases: one from stomach, two of the ascending colon and two cases of the upper rectum.

CONCLUSIONS

Gastrointestinal MANEC is a microsatellite stable tumor with nodular growth, which components might originate from a CD44-positive stem-like precursor cell. Lymph node status remains the most reliable prognostic parameter and agressivity seems to not be influenced by tumor budding degree or EMT-related features. The histologic aspect of metastatic component (neuroendocrine versus adenocarcinoma) should be included in the histopathological reports and might be used for establishing the proper-targeted therapy of MANEC.

[Neuroendocrine tumors of the stomach, duodenum and pancreas : Value of (hybrid) radiological diagnostics]

CLINICAL/METHODICAL ISSUE

Neuroendocrine tumors (NET) of the stomach, duodenum and pancreas are rare tumors with a low incidence but the exact tumor localization and staging diagnostics are of critical importance for further planning of treatment.

STANDARD RADIOLOGICAL METHODS

Standard primary diagnostic methods include multimodal imaging with computed tomography (CT) and magnetic resonance imaging (MRI) but in 20-50% of the cases the localization of the primary tumor cannot be identified.

METHODICAL INNOVATIONS

Modern hybrid imaging procedures combine radiological procedures and functional imaging, e.g. using somatostatin receptor (SSR) positron emission tomography CT (PET)/CT imaging. For the exact diagnostics of the primary tumor and distant metastases morphological and functional aspects can be combined for targeted diagnostics. For primary tumor staging a sensitivity of 80.0% and a specificity of 88.4% are given in the literature.

PERFORMANCE

The application of SSR PET/CT led to a change in patient management in 44% of all cases according to a recently published meta-analysis and therefore had a significant influence on the further procedure.

ASSESSMENT

The use of SSR PET/CT can provide critical information for further treatment and can lead to a significant change in treatment management in a relevant proportion of patients.

PRACTICAL RECOMMENDATIONS

Radiological imaging diagnostics and in particular hybrid functional imaging procedures using PET/CT will become increasingly more relevant for the diagnostics, treatment and follow-up of NET patients.

Gastric neuroendocrine neoplasias: manifestations and comparative outcomes

Although gastric neuroendocrine neoplasias (gNEN) are an orphan disease, their incidence is rising. The heterogeneous clinical course powers the ongoing discussion of the most appropriate classification system and management. Prognostic relevance of proposed classifications was retrospectively analysed in 142 patients from a single tertiary referral centre. Baseline, management and survival data were acquired for statistical analyses. The distribution according to the clinicopathological typification was gNEN-1 (n = 86/60.6%), gNEN-2 (n = 7/4.9%), gNEN-3 (n = 24/16.9%) and gNEN-4 (n = 25/17.6%), while hypergastrinemia-associated gNEN-1 and -2 were all low-grade tumours (NET-G1/2), formerly termed sporadic gNEN-3 could be subdivided into gNEN-3 with grade 1 or 2 and gNEN-4 with grade 3 (NEC-G3). During follow-up 36 patients died (25%). The mean overall survival (OS) of all gNEN was 14.2 years. The OS differed statistically significant across all subgroups with either classification system. According to UICC 2017 TNM classification, OS differed for early and advanced stages, while WHO grading indicated poorer prognosis for NEC-G3. Cox regression analysis confirmed the independent prognostic validity of either classification system for survival. Particularly careful analysis of the clinical course of gNEN-1 (ECLomas, gastric carcinoids) confirmed their mostly benign, but recurrent and extremely slowly progressive behaviour with low risk of metastasis (7%) and an efficient long-term control by repetitive endoscopic procedures. Our study provides evidence for the validity of current classifications focusing on typing, grading and staging. These are crucial tools for risk stratification, especially to differentiate gNEN-1 as well as sporadic gNET and gNEC (gNEN-3 vs -4).

Genetics and Epigenetics of Gastroenteropancreatic Neuroendocrine Neoplasms

Gastroenteropancreatic (GEP) neuroendocrine neoplasms (NENs) are heterogeneous regarding site of origin, biological behavior, and malignant potential. There has been a rapid increase in data publication during the last 10 years, mainly driven by high-throughput studies on pancreatic and small intestinal neuroendocrine tumors (NETs). This review summarizes the present knowledge on genetic and epigenetic alterations. We integrated the available information from each compartment to give a pathway-based overview. This provided a summary of the critical alterations sustaining neoplastic cells. It also highlighted similarities and differences across anatomical locations and points that need further investigation. GEP-NENs include well-differentiated NETs and poorly differentiated neuroendocrine carcinomas (NECs). NENs are graded as G1, G2, or G3 based on mitotic count and/or Ki-67 labeling index, NECs are G3 by definition. The distinction between NETs and NECs is also linked to their genetic background, as TP53 and RB1 inactivation in NECs set them apart from NETs. A large number of genetic and epigenetic alterations have been reported. Recurrent changes have been traced back to a reduced number of core pathways, including DNA damage repair, cell cycle regulation, and phosphatidylinositol 3-kinase/mammalian target of rapamycin signaling. In pancreatic tumors, chromatin remodeling/histone methylation and telomere alteration are also affected. However, also owing to the paucity of disease models, further research is necessary to fully integrate and functionalize data on deregulated pathways to recapitulate the large heterogeneity of behaviors displayed by these tumors. This is expected to impact diagnostics, prognostic stratification, and planning of personalized therapy.

Neuroendocrine Liver Metastasis-a Specific Set of Markers to Detect Primary Tumor Sites

The diagnosis of neuroendocrine neoplasia (NEN) is often made at an advanced stage of disease, including hepatic metastasis. At this point, the primary may still be unknown and sometimes cannot even be detected by functional imaging, especially in very small tumors of the pancreas (pan) and small intestinal (si) entities. The site of the primary may be based on biopsy specimens of the liver applying a specific set of markers. Specimens of liver metastases from 87 patients with NENs were studied. In retrospect, 50 patients had si and 37 pan NENs. Tissue samples were evaluated by immunohistochemistry. The markers applied were insulin gene enhancer protein Islet-1 (ISL-1), homeobox protein CDX-2 (CDX2), thyroid transcription factor 1 (TTF-1), and serotonin. Positive stains for CDX2 were documented in 43 (86%) and for serotonin in 45 (90%) of 50 siNENs. Three panNENs were positive for CDX2 and one for serotonin, respectively. ISL-1 was negative throughout in siNENs and also negative in 8 of 50 panNENs (21.6%). TTF-1 was negative in more than 90% of the specimens of either entity. Immunohistochemical markers in liver metastasis can lead the way to the site of the primary NEN. They should always be used in combined clusters.

Intertumor heterogeneity in 60 pancreatic neuroendocrine tumors associated with multiple endocrine neoplasia type 1

BACKGROUND

Patients with multiple endocrine neoplasia type 1 (MEN-1) develop multiple pancreatic neuroendocrine neoplasias (PNENs). Size at diagnosis and growth during follow-up are crucial parameters. According to the WHO 2017, grading is another important parameter. The impact of grading compared to size (WHO 2000) on the clinical course needs to be evaluated.

METHODS

Sixty PNENs of six patients with MEN-1 were retrospectively evaluated.

RESULTS

Fifty-one tumors with a diameter of < 20 mm were graded as G1. Two of 9 tumors with diameters of ≥20 mm were graded as G2. Tumor size of ≥20 mm correlated significantly with higher proliferation (p = 0.000617). Lymph node metastases were documented in two patients with a total of 19 tumors. In one patient, all 13 tumors (diameter: 0.4 to 100 mm) were classified as G1. However, metastases were documented in 9/29 lymph nodes. In the other patient, 5 tumors (3.5 to 20 mm) were classified as G1. The sixth tumor (30 mm) was classified as G2 (Ki-67: 8%). Metastases were revealed in 2/20 lymph nodes.

CONCLUSIONS

Tumor size of ≥20 mm seems to correlate with more aggressive MEN-1 related pancreatic disease, regardless of individual proliferation. Tumors ≥20 mm and tumors graded as G2 should be treated surgically regardless of their size.

Lower gastrointestinal neuroendocrine neoplasms associated with hereditary cancer syndromes: a case series

Lower gastrointestinal (GI) neuroendocrine neoplasms (NENs) of the colon and rectum are uncommon and not traditionally associated with hereditary GI cancer syndromes. However, with widespread implementation of colorectal cancer screening programs, lower GI NENs are being identified with increasing frequency. We report the first case series of six patients with lower GI NENs who were diagnosed with hereditary GI cancer syndromes by germline testing. Two patients presented with poorly differentiated rectal neuroendocrine carcinoma (NECs) with colonic polyposis and were found to have Familial Adenomatous Polyposis and MYH-Associated Polyposis, respectively. Three patients with colorectal NENs (one well differentiated neuroendocrine tumor, NET, and two NECs), all of which displayed abnormal immunohistochemistry for mismatch repair proteins, were diagnosed with Lynch syndrome. One patient with a goblet cell carcinoid was diagnosed with CHEK2 mutations. All patients met genetic testing guidelines and the diagnosis was made utilizing next generation sequencing gene panel tests. Lower GI NETs should therefore be considered a potential hereditary GI cancer syndrome-associated malignancy in patients who otherwise meet criteria for genetic evaluation.

The Role of Adding Somatostatin Analogues to Peptide Receptor Radionuclide Therapy as a Combination and Maintenance Therapy

Purpose: Although somatostatin analogues (SSA) and peptide receptor radionuclide therapy (PRRT) are validated therapies in patients with advanced gastroenteropancreatic neuroendocrine tumors (GEP-NET), it remains unclear whether SSA combined with PRRT or as maintenance therapy can provide prolonged survival compared with patients treated with PRRT alone. In this retrospective study, we aimed to investigate whether there is a survival benefit to adding SSA to PRRT as a combination therapy and/or maintenance therapy.Patients and Methods: The investigation included 168 patients with unresectable GEP-NETs treated at the University Hospital Bonn, Bonn, Germany. The patients were divided into two main groups: PRRT monotherapy (N = 81, group 1) and PRRT plus SSA (N = 87, group 2) as combined therapy with PRRT and/or as maintenance therapy after PRRT.Results: Data for overall survival (OS) were available from 168 patients, of whom 160 had data for progression-free survival (PFS). The median PFS was 27 months in group 1 versus 48 months in group 2 (P = 0.012). The median OS rates were 47 months in group 1 and 91 months in group 2 (P < 0.001). The death-event rates were lower in group 2 (26%) than in group 1 (63%). SSA as a combination therapy with PRRT and/or as a maintenance therapy showed a clinical benefit rate (objective response or stable disease) of 95%, which was significantly higher than group 1 (79%).Conclusions: SSA as a combination therapy and/or maintenance therapy may play a significant role in tumor control in patients with GEP-NET who underwent a PRRT. Clin Cancer Res; 24(19); 4672-9. ©2018 AACR.

Flushing Disorders Associated with Gastrointestinal Symptoms: Part 1, Neuroendocrine Tumors, Mast Cell Disorders and Hyperbasophila

Flushing is the subjective sensation of warmth accompanied by visible cutaneous erythema occurring throughout the body with a predilection for the face, neck, pinnae, and upper trunk where the skin is thinnest and cutaneous vessels are superficially located and in greatest numbers. Flushing can be present in either a wet or dry form depending upon whether neural-mediated mechanisms are involved. Activation of the sympathetic nervous system results in wet flushing, accompanied by diaphoresis, due to concomitant stimulation of eccrine sweat glands. Wet flushing is caused by certain medications, panic disorder and paroxysmal extreme pain disorder (PEPD). Vasodilator mediated flushing due to the formation and release of a variety of biogenic amines, neuropeptides and phospholipid mediators such as histamine, serotonin and prostaglandins, respectively, typically presents as dry flushing where sweating is characteristically absent. Flushing occurring with neuroendocrine tumors accompanied by gastrointestinal symptoms is generally of the dry flushing variant, which may be an important clinical clue to the differential diagnosis. A number of primary diseases of the gastrointestinal tract cause flushing, and conversely extra-intestinal conditions are associated with flushing and gastrointestinal symptoms. Gastrointestinal findings vary and include one or more of the following non-specific symptoms such as abdominal pain, nausea, vomiting, diarrhea or constipation. The purpose of this review is to provide a focused comprehensive discussion on the presentation, pathophysiology, diagnostic evaluation and management of those diseases that arise from the gastrointestinal tract or other site that may cause gastrointestinal symptoms secondarily accompanied by flushing. This review is divided into two parts given the scope of conditions that cause flushing and affect the gastrointestinal tract: Part 1 covers neuroendocrine tumors (carcinoid, pheochromocytomas, vasoactive intestinal polypeptide, medullary carcinoma of the thyroid), polyneuropathy, organomegaly, endocrinopathy, monoclonal protein, skin changes (POEMS), and conditions involving mast cells and basophils; while Part 2 covers dumping syndrome, mesenteric traction syndrome, rosacea, hyperthyroidism and thyroid storm, anaphylaxis, panic disorders, paroxysmal extreme pain disorder, and food, alcohol and medications.

Theranostics in nuclear medicine practice

The importance of personalized medicine has been growing, mainly due to a more urgent need to avoid unnecessary and expensive treatments. In nuclear medicine, the theranostic approach is an established tool for specific molecular targeting, both for diagnostics and therapy. The visualization of potential targets can help predict if a patient will benefit from a particular treatment. Thanks to the quick development of radiopharmaceuticals and diagnostic techniques, the use of theranostic agents has been continually increasing. In this article, important milestones of nuclear therapies and diagnostics in the context of theranostics are highlighted. It begins with a well-known radioiodine therapy in patients with thyroid cancer and then progresses through various approaches for the treatment of advanced cancer with targeted therapies. The aim of this review was to provide a summary of background knowledge and current applications, and to identify the advantages of targeted therapies and imaging in nuclear medicine practices.

Role of PD-L1 expression as a biomarker for GEP neuroendocrine neoplasm grading

Neuroendocrine neoplasms (NENs) are rare, heterogeneous and ubiquitous tumors commonly localized in the gastrointestinal tract, lung, and pancreas. The clinical behavior of NEN is highly unpredictable; in fact, low-grade cases can unexpectedly be associated with metastases. Currently, the 2010 WHO NEN classification employs histological differentiation and the proliferation index for grading tumors but fails to provide reliable prognostic and therapeutic indications. Therefore, there is an urgent need for a better characterization of G2/G3 NENs. Similar to several other tumors, NENs possess immune-escape mechanisms, but very little has yet been done to characterize this crucial aspect. There are no available data describing PD-L1 expression in these tumors. Here we provide, for the first time, evidence of PD-L1 tissue expression in gastroenteropancreatic neuroendocrine neoplasms (GEP-NENs). PD-L1 expression was significantly associated with a high-grade WHO classification (G3) (P<0.001) but not with gender, primary site, or lymph node status. The PD-L1 positivity rate and signal intensity are directly correlated (P<0.001) with a grade increase from G1 to G3. In particular in G3 cases, we observed a dichotomy between the morphology (WD- and PD-NENs) and Ki67. Moreover, our study demonstrated a significant association with the grade and PD-L1 expression levels in immune-infiltrating cells (P<0.001). In particular, G3 tumors are characterized by strong PD-L1 expression in both the tumor and infiltrating immune cells (P<0.001), reflecting an unfavorable environment for T-cell-mediated tumor aggression. These findings suggest that NENs might acquire resistance to immune surveillance by upregulating PD-L1 and inhibiting peritumoral and intratumoral infiltrating lymphocytes. Here we demonstrate that PD-L1 is currently the best-known biomarker for G3 NENs, becoming the new gold standard for G3 NEN discrimination. Furthermore, pharmacological approaches using anti-PD-1 antibodies may become the logical choice for the treatment of G3 cases with a poor prognosis.

Impact of Snail and E-cadherin expression in pancreatic neuroendocrine tumors

Pancreatic neuroendocrine tumors (PNETs) are a rare type of malignancy with a prognosis that is relatively good, compared with that of pancreatic adenocarcinoma. However, a number of patients with PNETs have distant metastasis and a less favorable prognosis. Epithelial-mesenchymal transition (EMT) is essential for tumor progression and metastasis. Snail and E-cadherin serve key roles in the process of EMT in numerous tumor types, including gastric and pancreatic adenocarcinoma. However, the role of EMT in PNETs remains unclear. The aim of the present study was to investigate the significance of Snail and E-cadherin expression in PNETs. Tissue samples were obtained from 40 resected PNETs. The expression of Snail and E-cadherin was evaluated in the primary tumors using immunohistochemical staining. The association between protein expression and patient clinicopathological features was then analyzed. High and low Snail expression levels were observed in 11 (27.5%) and 29 (72.5%) patients, respectively. Preserved and reduced E-cadherin expression was observed in 19 (47.5%) and 21 (52.5%) patients, respectively. Patients with low Snail expression and preserved E-cadherin expression had a significantly lower risk of vascular invasion, lymphatic invasion, lymph node metastasis and liver metastasis and a lower WHO classification, as compared with the group that included patients with high Snail and reduced E-cadherin, high Snail and preserved E-cadherin, and low Snail and reduced E-cadherin expression. In addition, the patients with low Snail expression levels and preserved E-cadherin expression had more a favorable prognosis compared with the other group. The present study indicates that EMT serves an important role in tumor progression in PNETs. Immunohistochemical evaluation of Snail and E-cadherin is useful for predicting the risk of vessel invasion and metastasis in PNETs.

Mixed Neuroendocrine-Nonneuroendocrine Neoplasms (MiNENs): Unifying the Concept of a Heterogeneous Group of Neoplasms

The wide application of immunohistochemistry to the study of tumors has led to the recognition that epithelial neoplasms composed of both a neuroendocrine and nonneuroendocrine component are not as rare as traditionally believed. It has been recommended that mixed neuroendocrine-nonneuroendocrine epithelial neoplasms are classified as only those in which either component represents at least 30 % of the lesion but this cutoff has not been universally accepted. Moreover, since their pathogenetic and clinical features are still unclear, mixed neuroendocrine-nonneuroendocrine epithelial neoplasms are not included as a separate clinicopathological entity in most WHO classifications, although they have been observed in virtually all organs. In the WHO classification of digestive tumors, mixed neuroendocrine-nonneuroendocrine neoplasm is considered a specific type and is defined as mixed adenoneuroendocrine carcinoma, a definition that has not been accepted for other organs. In fact, this term does not adequately convey the morphological and biological heterogeneity of digestive mixed neoplasms and has created some misunderstanding among both pathologists and clinicians. In the present study, we have reviewed the literature on mixed neuroendocrine-nonneuroendocrine epithelial neoplasms reported in the pituitary, thyroid, nasal cavity, larynx, lung, digestive system, urinary system, male and female genital organs, and skin to give the reader an overview of the most important clinicopathological features and morphological criteria for diagnosing each entity. We also propose to use the term "mixed neuroendocrine-nonneuroendocrine neoplasm (MiNEN)" to define and to unify the concept of this heterogeneous group of neoplasms, which show different characteristics mainly depending on the type of neuroendocrine and nonneuroendocrine components.

Multivariate analysis of metastasis‑related risk factors for patients with gastroenteropancreatic neuroendocrine tumors based on clinicopathological and endoscopic features

Gastroenteropancreatic neuroendocrine tumors (GEP‑NETs) are relatively uncommon. Unfortunately, epidemiological studies on the incidence of GEP‑NETs worldwide have reported a marked increase in the detection of these tumors. Although they often exhibit relatively indolent clinical courses, GEP‑NETs have the potential for lethal progression, especially in patients who present with advanced disease. Early detection and surgical removal is currently the only reliable curative treatment for GEP‑NET patients. The objective of this study was to analyze the clinicopathological characteristics of GEP‑NETs and explore the metastasis‑related risk factors of patients with GEP‑NETs. One hundred and forty‑six patients diagnosed pathologically with GEP‑NETs from January 2001 to January 2015 at the Second Xiangya Hospital of Central South University were retrospectively evaluated. We retrieved and analyzed information concerning clinical characteristics and metastasis‑related risk factors, and used Chi‑square test and logistic regression analysis to analyze the clinicopathological characteristics of GEP‑NETs and explore the association between tumor metastasis and possible related risk factors. The results revealed that the most common clinical manifestations were abdominal pain (n=88), alteration in the character of stool (n=58) and melaena (n=33). Rectum (91/146, 62.3%) and stomach (19/146, 13.0%) were the main sites of metastasis. Both Chi‑square test and logistic regression analysis showed that tumor size (P<0.05), tumor type (P=0.008) and peritumoral lymphatic vessel density (LVD) (P=0.004) were significantly correlated with tumor metastasis. Neither Chi‑square test nor logistic regression analysis indicated that gender (P>0.05), age (P>0.05), tumor location (P>0.05), tumor number (P>0.05), chromaffin granule protein A [chromogranin A (CgA), P>0.05], synaptophysin (Syn, P>0.05) or intratumoral LVD (P>0.05) had a significant correlation with tumor metastasis. Chi‑square test revealed that tumor grade was significantly correlated with tumor metastasis. In conclusion, GEP‑NETs may occur in multiple sites of the digestive system and lack specific clinical manifestations. Tumor size, tumor type, peritumoral LVD, total LVD and tumor grade are metastasis‑related risk factors for GEP‑NET patients.

Inverse expression of somatostatin and CXCR4 chemokine receptors in gastroenteropancreatic neuroendocrine neoplasms of different malignancy

INTRODUCTION

Somatostatin receptors (SSTR) are widely distributed in well-differentiated neuroendocrine neoplasms (NEN) and serve as primary targets for diagnostics and treatment. An overexpression of the chemokine receptor CXCR4, in contrast, is considered to be present mainly in highly proliferative and advanced tumors. Comparative data are still lacking, however, for neuroendocrine carcinomas (NEC).

METHODS

SSTR subtype (1, 2A, 3, 5) and CXCR4 expression was evaluated in G1 (n = 31), G2 (n = 47), and low (G3a; Ki-67: 21-49%; n = 21) and highly proliferative (G3b; Ki-67: >50%, n = 22) G3 (total n = 43) gastroenteropancreatic NEN samples by performing immunohistochemistry with monoclonal rabbit anti-human anti-SSTR and anti-CXCR4 antibodies, respectively, and was correlated with clinical data.

RESULTS

Both CXCR4 and SSTR were widely expressed in all tumors investigated. CXCR4 expression differed significantly between the G1 and G3 specimens and within the G3 group (G3a to G3b), and was positively correlated with Ki-67 expression. SSTR2A, in contrast, exhibited an inverse association with Ki-67. SSTR2A was highly expressed in G1 and G2 tumors, but was significantly less abundant in G3 carcinomas. Additionally, SSTR1 expression was higher in G3a than in G3b tumors.

CONCLUSION

We observed an elevation in CXCR4 and a decrease in SSTR2A expression with increasing malignancy. Interestingly, 23% of the G3 specimens had strong SSTR2A expression. Because CXCR4 was strongly expressed in highly proliferative G3 carcinomas, it is an interesting new target and needs to be validated in larger studies.

The ENETS/WHO grading system for neuroendocrine neoplasms of the gastroenteropancreatic system: a review of the current state, limitations and proposals for modifications

The understanding of neuroendocrine neoplasms has evolved significantly since their initial descriptions in the 1800s to early 1900s. In the gastroenteropancreatic system, this group of malignant tumors is subdivided into well and poorly differentiated neuroendocrine neoplasms based on morphologic, proliferative and biologic differences. However, it has become increasingly apparent that well-differentiated neuroendocrine tumors are not a homogeneous group. Attempting to better predict outcome of these tumors has been the motivation behind numerous proposed classification systems, the evolution of which culminated with the currently used system, the ENETS/WHO classification. Herein, we review the genesis of this classification system and some of its shortcomings. In addition, we discuss some of the most recent proposals that suggest modifications to the current system.

Comparison of the prognostic values of the 2010 WHO classification, AJCC 7th edition, and ENETS classification of gastric neuroendocrine tumors

The ability of the European Neuroendocrine Tumor Society (ENETS) system, 2010 World Health Organization (WHO) grading system, and American Joint Committee on Cancer (AJCC) staging system to predict survival after gastric neuroendocrine tumor (NET) resection has not yet been validated.We retrospectively evaluated 175 gastric NETs from 1996 to 2014. WHO grade 3 (G3) patients (n = 66) had a lower survival rate than grade 1 (G1) (n = 39) or grade 2 (G2) (n = 13) patients, with similar high survival rates for G1 and G2 patients. G3 patients had a lower survival rate than mixed-type patients (n = 57). Using the AJCC classification, most of the G1/2 NETs (86.6%) were confined to T1/T2, N0 tumor, and stage I/IIa, but the survival rate was not well distributed. In contrast, G3/mixed tumors were well distributed in terms of T, N, stage, and survival. Using the ENETS classification, 64.6% of the tumors were T2 and only 8.6% were T3. In addition, 49.7% were stage IIIb and only 1.9% was IIa, with poor survival distribution.Our findings strongly suggested that the WHO and ENETS classification systems have shown a low prognostic value. The AJCC TNM system showed a low prognostic value for well-differentiated NETs (G1 or G2). In contrast, the AJCC TNM system had a high prognostic value for G3 or mixed tumors.

Mixed adenoneuroendocrine carcinoma of the ampulla of Vater: A case report

Mixed adenoneuroendocrine carcinomas (MANECs) are rare biphasic tumour types, which are morphologically recognisable as both gland-forming and neuroendocrine neoplasms. Within the gastrointestinal tract, MANECs occur predominantly in the stomach or colorectum. The present study described a case of a MANEC originating from the ampullary region. The patient presented with widespread metastatic disease. Biopsy samples obtained from the ampullary primary tumour disclosed a complex lesion with adenocarcinoma and neuroendocrine small cell carcinoma components, positive for the intestinal transcription factor caudal type homeobox-2 and for neuroendocrine markers, including chromogranin A, synaptophysin, cluster of differentiation 56/neural cell adhesion molecule. By contrast, biopsy samples obtained from metastatic tissue revealed pure neuroendocrine carcinoma. As exemplified by this true mixed tumour, tumour heterogeneity evolves as the major challenge in oncology today, with potentially severe implications for the choice of chemotherapy. The assessment of metastatic sites may render valuable diagnostic information that is crucial for clinical decision-making and patient management.

Glutaminases in slowly proliferating gastroenteropancreatic neuroendocrine neoplasms/tumors (GEP-NETs): Selective overexpression of mRNA coding for the KGA isoform

Glutamine (Gln) is a crucial metabolite in cancer cells of different origin, and the expression and activity of different isoforms of the Gln-degrading enzyme, glutaminase (GA), have variable implications for tumor growth and metabolism. Human glutaminases are encoded by two genes: the GLS gene encodes the kidney-type glutaminases, KGA and GAC, while the GLS2 gene encodes the liver-type glutaminases, GAB and LGA. Recent studies suggest that the GAC isoform and thus high GAC/KGA ratio, are characteristic of highly proliferating tumors, while GLS2 proteins have an inhibitory effect on tumor growth. Here we analyzed the expression levels of distinct GA transcripts in 7 gastroenteropancreatic neuroendocrine tumors (GEP-NETs) with low proliferation index and 7 non-neoplastic tissues. GEP-NETs overexpressed KGA, while GAC, which was the most abundant isoform, was not different from control. The expression of the GLS2 gene showed tendency towards elevation in GEP-NETs compared to control. Collectively, the expression pattern of GA isoforms conforms to the low proliferative capacity of GEP-NETs encompassed in this study.

Neuroendocrine tumors of the pancreas: a retrospective single-center analysis using the ENETS TNM-classification and immunohistochemical markers for risk stratification

Background

This study was performed to assess the 2006 introduced ENETS TNM-classification with respect to patient survival and surgical approach for patients who underwent surgery for a neuroendocrine tumor of the pancreas (PNET).

Methods

Between 2001 and 2010 38 patients after resection of a PNET were investigated regarding tumor localization and size. Further, patient survival with regards to the new TNM-classification, the operation methods and immunohistochemical markers was analyzed.

Results

The estimated mean survival time of the 38 patients was 91 ± 10 months (female 116 ± 9, male 56 ± 14 months; p = 0.008). The 5-year survival rate was 63.9%. Patient survival differed significantly depending on tumor size (pT1 107 ± 13, pT2 94 ± 16, pT3 44 ± 7 and pT4 18 ± 14 months; P = 0.006). Patients without lymph node metastasis survived significantly longer compared to patients with positive lymph node status (108 ± 9 vs. 19 ± 5 months; P < 0.001). However, survival in patients with and without distant metastasis did not differ significantly (92 ± 11 vs. 80 ± 23 months; P = 0.876). Further, the tumor grading significantly influenced patient survival (G1 111 ± 12, G2 68 ± 12 and G3 21 ± 14 months; P = 0.037).

Conclusions

As part of the TNM-classification especially lymph node status and also tumor size and grading were identified as important factors determining patient survival. Further, gender was demonstrated to significantly influence survival time. If an R0 resection was achieved in patients with distant metastases patient survival was comparable to patients without metastasis.

Electronic supplementary material

The online version of this article (doi:10.1186/s12893-015-0033-1) contains supplementary material, which is available to authorized users.

CTNNB1 mutational analysis of solid-pseudopapillary neoplasms of the pancreas using endoscopic ultrasound-guided fine-needle aspiration and next-generation deep sequencing

BACKGROUND

Solid-pseudopapillary neoplasm (SPN), a rare neoplasm of the pancreas, frequently harbors mutations in exon 3 of the cadherin-associated protein beta 1 (CTNNB1) gene. Here, we analyzed SPN tissue for CTNNB1 mutations by deep sequencing using next-generation sequencing (NGS).

METHODS

Tissue samples from 7 SPNs and 31 other pancreatic lesions (16 pancreatic ductal adenocarcinomas (PDAC), 11 pancreatic neuroendocrine tumors (PNET), 1 acinar cell carcinoma, 1 autoimmune pancreatitis lesion, and 2 focal pancreatitis lesions) were analyzed by NGS for mutations in exon 3 of CTNNB1.

RESULTS

A single-base-pair missense mutations in exon 3 of CTNNB1 was observed in all 7 SPNs and in 1 of 11 PNET samples. However, mutations were not observed in the tissue samples of any of the 16 PDAC or other four pancreatic disease cases. The variant frequency of CTNNB1 ranged from 5.4 to 48.8 %.

CONCLUSIONS

Mutational analysis of CTNNB1 by NGS is feasible and was achieved using SPN samples obtained by endoscopic ultrasound-guided fine needle aspiration.

Comparison of World Health Organization 2000/2004 and World Health Organization 2010 classifications for gastrointestinal and pancreatic neuroendocrine tumors

Gastroenteropancreatic neuroendocrine tumors (GEPNETs) were divided into 4 groups based on tumor diameter and stage in World Health Organization (WHO) 2000/2004 classification as well-differentiated endocrine tumor benign (WDETB), well-differentiated endocrine tumor with uncertain behavior (WDETUB), well-differentiated endocrine carcinoma (WDEC), and poorly differentiated endocrine carcinoma (PDEC). World Health Organization 2000/2004 was not widely accepted because of stage-related classification and the category of "uncertain behavior." The European NET Society proposed a grading classification and site-specific staging system in 2010. Gastroenteropancreatic NETs were divided into 3 groups as NET grade 1 (G1), NET grade 2 (G2), and neuroendocrine carcinoma (NEC) grade 3 (G3) based on mitoses and the Ki-67 index. We evaluated 63 GEPNET cases according to both classifications. We compared two classifications and the tumor groups in terms of prognostic parameters (diameter, mitosis, Ki-67 index, angioinvasion, perineural invasion, necrosis, and metastasis) and pathologic stage. All 14 cases diagnosed as PDEC were included in the NEC G3 according to WHO 2010. Seventeen cases were diagnosed as WDETB, 9 as WDETUB, and 23 as WDEC. There was statistically significant difference between these groups in terms of all prognostic parameters except for necrosis, mitosis, Ki-67 index, and grade. All WDETB cases, 89% of WDETUBs, and 87% of WDECs were included in the NET G1. There were 45 cases evaluated as NET G1 and 4 cases as NET G2 according to WHO 2010. Metastasis and perineural invasion were more common in NET G2, no significant differences in other parameters. In conclusion, WHO 2010 is easier to use, whereas WHO 2000/2004 shows higher correlation with prognosis. However, it includes benign and uncertain behavior categories, although small tumors with low proliferative activity can also cause metastases. All GEPNETs should be considered potentially malignant.

Survival analysis and prognostic factors for neuroendocrine tumors in Turkey

BACKGROUND

This study aimed to determine the demographical distribution, survival and prognostic factors for neuroendocrine tumors monitored in our clinic.

MATERIALS AND METHODS

Data for 52 patients who were admitted to Cumhuriyet University Medical Faculty Training Research and Practice Hospital Oncology Center between 2006 and 2012 and were diagnosed and treated for neuroendocrine tumors were investigated.

RESULTS

Of the total, 30 (58%) were females and 22 (42%) were males. The localization of the disease was gastroenteropancreatic in 29 (56%) patients and other sites in 23 (44%). The most frequently involved organ in the gastroenteropancreatic system was the stomach (n=10, 19%) and the most frequently involved organ in other regions was the lungs (n=10, 19%). No correlation was found between immunohistochemical staining for proteins such as chromogranin A, synaptophysin, and NSE and the grade of the tumor. The patients were followed-up at a median of 24 months (1-90 months). The three-year overall survival rate was 71%: 100% in stage I, 88% in stage II, 80% in stage III, and 40% in stage IV. The three-year survival rate was 78% in tumors localized in the gastroenteropancreatic region, and 54% in tumors localized in other organs. In the univariate analysis, gender, age, performance status of the patients, grade, localization, surgical treatment, and neutrophil/ lymphocyte ratio (≤ 5 versus >5) affected the prognosis of the patients.

CONCLUSIONS

Most of the tumors were localized in the gastroenteropancreatic region, and the three-year survival rate in tumors localized in this region was better than the tumors localized in other sites. Surgical treatment was a positive independent prognostic factor, whereas Grade 3 and a neutrophil/lymphocyte ratio of >5 were negative independent prognostic factors.

Somatostatin receptor 2 and 5 expressions in gastroenteropancreatic neuroendocrine tumors in Turkey

BACKGROUND

Gastroenteropancreatic neuroendocrine tumors (GNs) are slow growing and although their incidence has increased in recent years, they are relatively rarely seen. Somatostatin analogues are used in the treatment of GNs that express somatostatin receptor (SR). We aimed to investigate the expression of SR2 and SR5 in GNs.

MATERIALS AND METHODS

In this study the expression of SR2 and SR5 was investigated immunohistochemically in 49 cases (26 males, 23 females) diagnosed and graded with GN according to the World Health Organization classification 2010.

RESULTS

The percentage of SR2 staining was 91.0% in grade 1, 82.8% in grade 2 and 100% in grade 3. On the other hand, the percentage of SR5 staining was 81.8% % in grade 1, 60.0% in grade 2 and 0% in grade 3. According to the tumor localization, the percentages of SR2 expression were as follows: pancreas 85.7%, stomach 100%, small bowel 70%, appendix 85.7% and rectum 100%. The percentages of SR5 expression were: pancreas 61,9%, stomach 37.5%, small bowel 70%, appendix 71.5% and rectum 66.6%. There was a significant negative correlation between ki67 percentage and SR5 expression (r=-0.341, p=0.016).

CONCLUSIONS

In this study, GNs were found to highly express SR2 and SR5. Although the expression of SR2 and SR5 changed according to tumor localization, the expression of SR2 was higher than the expression of SR5 in GN. There was a significant negative correlation between ki67 and SR5. Accordingly, SR5 may be a prognostic indicator of GN.

Contrast enhancement pattern on multidetector CT predicts malignancy in pancreatic endocrine tumours

OBJECTIVES

Preoperative suspicion of malignancy in pancreatic neuroendocrine tumours (pNETs) is mostly based on tumour size. We retrospectively reviewed the contrast enhancement pattern (CEP) of a series of pNETs on multiphasic multidetector computed tomography (MDCT), to identify further imaging features predictive of lesion aggressiveness.

METHODS

Sixty pNETs, diagnosed in 52 patients, were classified based on CEP as: type A showing early contrast enhancement and rapid wash-out; type B presenting even (B1) or only (B2) late enhancement. All tumours were resected allowing pathologic correlations.

RESULTS

Nineteen pNETs showed type A CEP (5-20 mm), 29 type B1 CEP (5-80 mm) and 12 type B2 (15-100 mm). All tumours were classified as well differentiated tumours, 19 were benign (WDt-b), 15 with uncertain behaviour (WDt-u) and 26 carcinomas (WDC). None of A lesions were malignant (12 WDt-b; 7 WDt-u), all B2 lesions were WDC, 7 B1 lesions were WDt-b, 8 WDt-u and 14 WDC; 4/34 (12 %) lesions ≤2cm were WDC. CEP showed correlation with all histological prognostic indicators.

CONCLUSIONS

Correlating with the lesion grading and other histological prognostic predictors, CEP may preoperatively suggest the behaviour of pNETs, assisting decisions about treatment. Moreover CEP allows recognition of malignant small tumours, incorrectly classified on the basis of their dimension.

A tale of two tumors: treating pancreatic and extrapancreatic neuroendocrine tumors

Despite their perceived rarity, gastroenteropancreatic neuroendocrine tumors (GEP-NETs) are rising in incidence and prevalence. The biology, natural history, and therapeutic options for GEP-NETs are heterogeneous: NETs arising in the pancreas can be distinguished from those arising elsewhere in the gastrointestinal tract, and therapy is dichotomized between these two groups. Somatostatin analogues are the mainstay of oncologic management of bowel NETs; everolimus, streptozocin, and sunitinib are approved to treat pancreatic NETs. There are significant differences in molecular genetics between pancreatic and extrapancreatic NETs, and studies are evaluating whether additional NET patients may benefit from targeted agents. We discuss the distinguishing features of these two groups of tumors, as well as the therapeutic implications of the distinction. We also examine the evolving therapeutic landscape and discuss the likelihood that treatment will be developed independently for pancreatic and extrapancreatic gastrointestinal NETs, with novel therapeutics effective for newly identified pathologically or molecularly defined subgroups.

The role of 68-Ga-DOTATOC CT-PET in surgical tactic for gastric neuroendocrine tumors treatment: our experience: a case report

Gastric neuroendocrine tumors (g-NETs), which originate from gastric enterochromaffin-like (ECL) mucosal cells and account for 2.4% of all carcinoids, are increasingly recognized due to expanding indications of upper gastrointestinal endoscopy. Often silent and benign, g-NETs may however, be aggressive and sometimes they mimic the course of gastric adenocarcinoma. Current nosography distinguishes those occurring in chronic conditions with hypergastrinemia, as the type 1 associated with chronic atrophic gastritis, and the type 2 associated with Zollinger-Ellison syndrome in MEN1. Conversely, type 3 and 4 (according to some authors) are unrelated to hypergastrinemia and are frequently malignant, with a propension to develop distant metastases. While there is a general agreement concerning the treatment of malignant gastric neuroendocrine tumors, for types 1 and 2, current possibilities include surveillance, endoscopic polypectomy, surgical excision, associated or not with surgical antrectomy, or total gastrectomy. This report, based on our clinical experience, discusses how the size, number, depth, histological grading, staging with CT, MRI, and the use of recently developed somatostatin receptor tracers (68Ga-DOTATATE, 68Ga-DOTA-TOC) could allow the correct identification of a benign or malignant propensity of an individual tumor, thus avoiding underestimation or overtreatment of these uncommon neoplasms.

Spectrum of Gastroenteropancreatic NENs in Routine Histological Examinations of Bioptic and Surgical Specimen: A Study of 161 Cases Collected from 17 Departments of Pathology in the Czech Republic

Objective. To characterize GEP-NENs in routine biopsies and surgical specimen in the Czech Republic and to evaluate how WHO Classification (2010) is acceptable in diagnostic practice. Methods. Paraffin-embedded blocks and bioptic reports were collected from 17 departments of pathology. Histologic slides were stained with H&E and immunohistologically for CgA, synaptophysin, and Ki-67. Results. Out of 28 gastric NENs, there were 22 NETs, G1, 5 NETs, G2, and 1 NEC. Ten duodenal NENs were NETs, G1. Among 27 NENs of jejunum and ileum, 23 were NETs, G1, 2 NETs, G2, and 1 NEC and 1 mixed adenoneuroendocrine carcinoma (MANEC). Among 42 appendiceal “incidentalomas”, 39 were NETs G1, 2 goblet cell carcinoids, and 1 MANEC. Out of 34 large intestinal NENs, 30 were NETs, G1, 3 NETs, G2, and 1 NEC. One small intestinal and 6 large bowel neoplasms were reclassified as poorly differentiated adenocarcinomas. In 12 pancreatic NENs, there were 7 NETs, G1, 3 NETs, G2, and 2 NECs. Conclusions. Our study demonstrates differences in GEP-NENs frequency in sites of origin in our region, comparing to other countries. Regarding routine bioptic diagnostics, we gave evidence that the WHO 2010 classification of NENs is fully acceptable for exact categorisation of tumours.

Angiogenesis and vascular maturation in neuroendocrine tumors

Neuroendocrine tumors (NETs) are highly vascularized, but the process of proliferation and maturation of vascular structures during tumor development and progression has remained unknown. We examined the structural alterations of intratumoral blood vessels in human gastroenteropancreatic NET. Microvessel density was evaluated using the endothelial cell markers vasohibin-1 (VASH-1), CD31, and endoglin in 135 cases. Double immunohistochemistry staining was performed to localize endothelium and pericytes on the same vessels using the pericyte marker nestin. The ratio of Ki-67/CD31 was significantly correlated with that of VASH-1/CD31 positivity (P<.001), indicating that the ratio of VASH-1/CD31 also reflects the status of neovascularization in NET. This ratio was higher in NET than in its nonneoplastic counterpart (P=.10) and tended to increase according to World Health Organization (WHO) grade, although the differences were not statistically significant (P=.32). The ratio of VASH-1/nestin-positive vessels, representing the maturation of neovessels, was also significantly higher in NET than in its nonneoplastic counterparts (P=.003). Among WHO grades, the ratio increased from grade 1 to grade 2 (P=.36) and decreased in neuroendocrine carcinoma (P=.34). Our results demonstrated that VASH-1/CD31 can be an ideal immunohistochemical marker for characterizing neovascularization in NET. The VASH-1/CD31 content increased with WHO grade, and the vessels covered by pericytes decreased in higher grades. These structural changes in the vessels are considered to play an important role in inducing tumor-cell proliferation.