Neuroendocrine neoplasms of the gut and pancreas: new insights

A new schedule of one week on/one week off temozolomide as second-line treatment of advanced neuroendocrine carcinomas (TENEC-TRIAL): a multicenter, open-label, single-arm, phase II trial

BACKGROUND

There is no consensus on the second-line treatment of patients with progressive high-grade neuroendocrine neoplasms (NENs G3) and large-cell lung neuroendocrine carcinoma. These patients generally have poor performance status and low tolerance to combination therapy. In this trial, we aim to evaluate the efficacy and safety of temozolomide given every other week in patients with advanced platinum-pretreated NENs G3.

PATIENTS AND METHODS

This trial is an open-label, non-randomized, phase II trial. Patients with platinum-pretreated metastatic neuroendocrine carcinoma were treated with 75 mg/m2/day of temozolomide for 7 days, followed by 7 days of no treatment (regimen one week on/one week off). The primary endpoint was the overall response rate. Secondary endpoints included progression-free survival (PFS), overall survival (OS), safety and tolerability. This study is registered with ClinicalTrials.gov, NCT04122911.

RESULTS

From 2017 to 2020, 38 patients were enrolled. Among the patients with determined Ki67, 12 out of 36 (33.3%) had a Ki67 index <55% and the remaining 24 out of 36 (66.6%) had an index ≥55%. Overall response rate was 18% (7/38), including one complete response and six partial responses. The median PFS was 5.86 months [95% confidence interval (CI) 4.8 months-not applicable) and the median OS was 12.1 months (95% CI 5.6-20.4 months). The 1-year PFS rate was 37%. No statistically significant difference in median PFS [hazard ratio 1.3 (95% CI 0.6-2.8); P = 0.44] and median OS [hazard ratio 1.1 (95% CI 0.5-2.4); P = 0.77] was observed among patients with Ki67 <55% versus ≥55%. Only G1-G2 adverse events were registered, the most common being G1 nausea, diarrhea and abdominal pain.

CONCLUSION

One week on/one week off temozolomide shows promising activity in patients with poorly differentiated NEN. The good safety profile confirmed the possibility of using this scheme in patients with poor performance status.

Radiomics analysis from magnetic resonance imaging in predicting the grade of nonfunctioning pancreatic neuroendocrine tumors: a multicenter study

OBJECTIVES

To explore the potential of radiomics features to predict the histologic grade of nonfunctioning pancreatic neuroendocrine tumor (NF-PNET) patients using non-contrast sequence based on MRI.

METHODS

Two hundred twenty-eight patients with NF-PNETs undergoing MRI at 5 centers were retrospectively analyzed. Data from center 1 (n = 115) constituted the training cohort, and data from centers 2-5 (n = 113) constituted the testing cohort. Radiomics features were extracted from T2-weighted images and the apparent diffusion coefficient. The least absolute shrinkage and selection operator was applied to select the most important features and to develop radiomics signatures. The area under receiver operating characteristic curve (AUC) was performed to assess models.

RESULTS

Tumor boundary, enhancement homogeneity, and vascular invasion were used to construct the radiological model to stratify NF-PNET patients into grade 1 and 2/3 groups, which yielded AUC of 0.884 and 0.684 in the training and testing groups. A radiomics model including 4 features was constructed, with an AUC of 0.941 and 0.871 in the training and testing cohorts. The fusion model combining the radiomics signature and radiological characteristics showed good performance in the training set (AUC = 0.956) and in the testing set (AUC = 0.864), respectively.

CONCLUSION

The developed model that integrates radiomics features with radiological characteristics could be used as a non-invasive, dependable, and accurate tool for the preoperative prediction of grade in NF-PNETs.

CLINICAL RELEVANCE STATEMENT

Our study revealed that the fusion model based on a non-contrast MR sequence can be used to predict the histologic grade before operation. The radiomics model may be a new and effective biological marker in NF-PNETs.

KEY POINTS

The diagnostic performance of the radiomics model and fusion model was better than that of the model based on clinical information and radiological features in predicting grade 1 and 2/3 of nonfunctioning pancreatic neuroendocrine tumors (NF-PNETs). Good performance of the model in the four external testing cohorts indicated that the radiomics model and fusion model for predicting the grades of NF-PNETs were robust and reliable, indicating the two models could be used in the clinical setting and facilitate the surgeons' decision on risk stratification. The radiomics features were selected from non-contrast T2-weighted images (T2WI) and diffusion-weighted imaging (DWI) sequence, which means that the administration of contrast agent was not needed in grading the NF-PNETs.

The Spectrum of Endocrine Pathology

Endocrine pathology comprises a spectrum of disorders originating in various sites throughout the body. Some disorders affect endocrine glands, and others arise from endocrine cells that are dispersed in non-endocrine tissues. Endocrine cells can broadly be classified as neuroendocrine, steroidogenic, or thyroid follicular cells; these three families have distinct embryologic origins, morphologic structure, and biochemical hormone synthetic pathways. Lesions affecting the endocrine system include developmental abnormalities, inflammatory processes that can be infectious or autoimmune, hypofunction with atrophy or hyperfunction caused by hyperplasia secondary to pathology in other sites, and neoplasia of many types. Understanding endocrine pathology requires knowledge of both structure and function, including the biochemical signaling pathways that regulate hormone synthesis and secretion. Molecular genetics has clarified sporadic and hereditary disease that is common in this field.

Application of Machine Learning in Predicting Hepatic Metastasis or Primary Site in Gastroenteropancreatic Neuroendocrine Tumors

Gastroenteropancreatic neuroendocrine tumors (GEP-NETs) account for 80% of gastroenteropancreatic neuroendocrine neoplasms (GEP-NENs). GEP-NETs are well-differentiated tumors, highly heterogeneous in biology and origin, and are often diagnosed at the metastatic stage. Diagnosis is commonly through clinical symptoms, histopathology, and PET-CT imaging, while molecular markers for metastasis and the primary site are unknown. Here, we report the identification of multi-gene signatures for hepatic metastasis and primary sites through analyses on RNA-SEQ datasets of pancreatic and small intestinal NETs tissue samples. Relevant gene features, identified from the normalized RNA-SEQ data using the mRMRe algorithm, were used to develop seven Machine Learning models (LDA, RF, CART, k-NN, SVM, XGBOOST, GBM). Two multi-gene random forest (RF) models classified primary and metastatic samples with 100% accuracy in training and test cohorts and >90% accuracy in an independent validation cohort. Similarly, three multi-gene RF models identified the pancreas or small intestine as the primary site with 100% accuracy in training and test cohorts, and >95% accuracy in an independent cohort. Multi-label models for concurrent prediction of hepatic metastasis and primary site returned >98.42% and >87.42% accuracies on training and test cohorts, respectively. A robust molecular signature to predict liver metastasis or the primary site for GEP-NETs is reported for the first time and could complement the clinical management of GEP-NETs.

Panic at the Bile Duct: How Intrahepatic Cholangiocytes Respond to Stress and Injury

In the liver, biliary epithelial cells (BECs) line intrahepatic bile ducts (IHBDs) and are primarily responsible for modifying and transporting hepatocyte-produced bile to the digestive tract. BECs comprise only 3% to 5% of the liver by cell number but are critical for maintaining choleresis through homeostasis and disease. To this end, BECs drive an extensive morphologic remodeling of the IHBD network termed ductular reaction (DR) in response to direct injury or injury to the hepatic parenchyma. BECs are also the target of a broad and heterogenous class of diseases termed cholangiopathies, which can present with phenotypes ranging from defective IHBD development in pediatric patients to progressive periductal fibrosis and cancer. DR is observed in many cholangiopathies, highlighting overlapping similarities between cell- and tissue-level responses by BECs across a spectrum of injury and disease. The following core set of cell biological BEC responses to stress and injury may moderate, initiate, or exacerbate liver pathophysiology in a context-dependent manner: cell death, proliferation, transdifferentiation, senescence, and acquisition of neuroendocrine phenotype. By reviewing how IHBDs respond to stress, this review seeks to highlight fundamental processes with potentially adaptive or maladaptive consequences. A deeper understanding of how these common responses contribute to DR and cholangiopathies may identify novel therapeutic targets in liver disease.

Immunoreactivity of HOXB13 in Neuroendocrine Neoplasms Is a Sensitive and Specific Marker of Rectal Well-Differentiated Neuroendocrine Tumors

HoxB13 is a transcription factor involved in defining of posterior endodermal derivatives, including prostate and rectum. While it is used as a marker of prostatic adenocarcinoma, it has not been studied systematically in neuroendocrine neoplasms. Thus, we performed HoxB13 immunohistochemistry in tissue microarrays and the whole sections of 232 neuroendocrine neoplasms. These included 34 paragangliomas (PGs), 20 cauda equina neuroendocrine tumors (CENETs), 123 well-differentiated neuroendocrine tumors (WDNETs), and 55 neuroendocrine carcinomas (NECs). WDNETs were additionally analyzed with SATB2, and colorectal WDNETs with CDX2 and serotonin immunohistochemistry. In total, HoxB13 immunoreactivity was observed in 95% (19/20) CENETs, 10.6% (13/123) WDNETs, and 12.9% (7/54) NECs. No PGs were positive. Large intestine WDNETs expressed HoxB13 in 68.4% (13/19); five negative tumors originated in cecum and one in rectum. In rectum, 92.9% (13/14) WDNETs expressed HoxB13. HoxB13 was 92.9% sensitive and 100% specific, showing 100% positive predictive value for the rectal origin of WDNET. In NECs, HoxB13 was positive in 15.4% (2/13) GIT tumors and 80% (4/5) prostatic NECs, but in none of urinary bladder NECs (0/8). SATB2 was positive in 17.1% (21/123) WDNETs, including 78.9% (15/19) of colorectal WDNETs, 71.4% (5/7) appendiceal WDNETs, and 2.9% (1/34) small intestine WDNETs. All 4 SATB2-negative large bowel tumors originated in the cecum. When both markers combined, HoxB13+/SATB2+ immunoprofile was seen exclusively in rectal WDNETs (positive predictive value 100%), while HoxB13-/SATB2+ immunoprofile was highly suggestive of the appendiceal origin (positive predictive value 71.4%). Therefore, HoxB13 can be useful as an immunohistochemical marker of rectal WDNETs and prostatic NECs.

A Systematic Review and Meta-Analysis of Prevalence and Outcomes of Cardiac Metastasis of Neuroendocrine Malignancies

Neuroendocrine tumors (NETs) are a rare group of malignancies which are aggressive and widely metastatic. Cardiac metastases (CMs) are rarely reported because of NET. We aim to analyze the available literature to study the proportional prevalence of CM because of NET and its location and effect on the ejection fraction (EF) and survival rate. Our search strategy and meta-analysis are in line with Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) AMSTAR-2 (Assessing the methodological quality of systematic Reviews-2) Guidelines. A literature search was conducted on MEDLINE (EMBASE and PubMed) for randomized clinical trials, pilot trials, and retrospective and prospective studies. Statistical analysis was performed using the CRAN-R software (https://CRAN.R-project.org/doc/FAQ/R-FAQ.html). The quality assessment of the included articles was performed using the Cochrane Risk of Bias and Newcastle-Ottawa Scale. A total of 16,685 patients were included in the study. The mean age of patients included in the study was 61.28 ± SD 9.89 years. Of these, 257 patients had a total of 283 CM. Metastasis was mainly located in the left ventricle with a pooled proportion of 0.48, 95% confidence interval (CI) 0.4 to 0.56, pericardium: 0.34, 95% CI 0.19 to 0.53, right ventricle 0.28, 95% CI 0.16 to 0.44, interventricular septum 0.25, 95% CI 0.16 to 0.37, left atrium 0.1, 95% CI 0.03 to 0.26 and right atrium 0.05, 95% CI 0.01 to 0.20. Decrease in EF at the time of CM diagnosis was the effect most consistently reported in patients with CM. Pooled mean survival was 35.89, 95% CI 8.27 to 155.68 months after the diagnosis of CM. CM due to NET was <2% and the left ventricle is the most common metastatic location, followed by the pericardium. Decreased EF was the most common clinical picture observed. Further studies are needed to analyze the clinical impact of NET CM.

The Surgical and Therapeutic Activities of Non-Functional Pancreatic Neuroendocrine Tumors at a High-Volume Institution

BACKGROUND

This study aimed to summarize the surgical and therapeutic activities of non-functional pancreatic neuroendocrine tumors (NF-PanNETs) and perform survival analyses of a 15-year single-institutional cohort of NF-PanNETs.

METHODS

In total, 1001 patients with neuroendocrine neoplasms treated at Fudan University Shanghai Cancer Center were screened for inclusion, and 509 patients with NF-PanNETs from 2006 to 2020 were included. For time trend analyses, the 15-year study period was randomly divided into three periods. Survival analyses used the Kaplan-Meier method and Cox regression models.

RESULTS

The total number of resected NF-PanNETs increased over the 15-year study period, from 5 resections in 2006 to 94 resections in 2020. A significant decrease in the tumor size was observed, from a mean of 4.0 cm to 3.3 cm, and to 3.0 cm in the most recent period (p = 0.006). Minimally invasive techniques gradually increased from 3.5% to 12.9%, and finally to 46.4% in the most recent period (p < 0.001). In non-metastatic and resected tumors, the tumor size (p < 0.001), positive lymph node (p < 0.001), adjuvant treatment (p = 0.048), and tumor grade (p < 0.001) were independent prognostic factors for recurrence-free survival (RFS). The microvascular invasion (p = 0.024) and tumor grade (p = 0.013) were independent prognostic factors for overall survival (OS). A malignant transformation from NET into neuroendocrine carcinoma was observed.

CONCLUSIONS

An increasing number of NF-PanNETs resection and minimally invasive surgery was shown. In non-metastatic and resected tumors NF-PanNETs, tumor size, positive lymph node, adjuvant treatment, and tumor grade were independent predictors of RFS. Microvascular invasion and tumor grade were independent prognostic factors for OS.

Aberrant transcription factors in the cancers of the pancreas

Transcription factors (TFs) are essential for proper activation of gene set during the process of organogenesis, differentiation, lineage specificity. Reactivation or dysregulation of TFs regulatory networks could lead to deformation of organs, diseases including various malignancies. Currently, understanding the mechanism of oncogenesis became necessity for the development of targeted therapeutic strategy for different cancer types. It is evident that many TFs go awry in cancers of the pancreas such as pancreatic ductal adenocarcinoma (PDAC) and pancreatic neuroendocrine neoplasms (PanNENs). These mutated or dysregulated TFs abnormally controls various signaling pathways in PDAC and PanNENs including RTK, PI3K-PTEN-AKT-mTOR, JNK, TGF-β/SMAD, WNT/β-catenin, SHH, NOTCH and VEGF which in turn regulate different hallmarks of cancer. Aberrant regulation of such pathways have been linked to the initiation, progression, metastasis, and resistance in pancreatic cancer. As of today, a number of TFs has been identified as crucial regulators of pancreatic cancer and a handful of them shown to have potential as therapeutic targets in pre-clinical and clinical settings. In this review, we have summarized the current knowledge on the role and therapeutic usefulness of TFs in PDAC and PanNENs.

Pancreatic adenocarcinoma and pancreatic high-grade neuroendocrine carcinoma: two sides of the moon

Pancreatic adenocarcinoma is the seventh leading cause of cancer death in the world and the most common type pf pancreatic cancer. Unfortunately, less than 20% of patients are surgically resectable and the great majority of cases are treated with palliative chemotherapy with unsatisfactory results. No targeted agents or personalized approaches have been validated in the last decades. On the other side, neuroendocrine neoplasms of the pancreas are generally considered indolent tumours. However, high-grade neuroendocrine carcinoma is a rare subtype of neuroendocrine neoplasm of the pancreas (accounting up to 10% of the neuroendocrine neoplasms of the pancreas), with particularly aggressive behaviour and poor prognosis. Even in this case, the treatment is represented by palliative chemotherapy with dismal results and no personalized therapies are available, so far. Notably, the quality of life of these patients is disappointingly low and the future perspectives of more personalized diagnostic and therapeutic strategies are scarce. In this review, we discuss relevant and current information on epidemiology, pathology, diagnosis, clinical presentation, treatment and ongoing clinical trials of these two entities, in order to illustrate the two sides of the moon.

Paraneoplastic syndromes: A focus on pathophysiology and supportive care

DISCLAIMER

In an effort to expedite the publication of articles, AJHP is posting manuscripts online as soon as possible after acceptance. Accepted manuscripts have been peer-reviewed and copyedited, but are posted online before technical formatting and author proofing. These manuscripts are not the final version of record and will be replaced with the final article (formatted per AJHP style and proofed by the authors) at a later time.

PURPOSE

This article aims to increase awareness of, outline pathophysiology for, and offer guidance on supportive care strategies for specific endocrine, neurological, and immunological syndromes associated with paraneoplastic syndromes (PNSs).

SUMMARY

PNS refers to remote effects that cannot be attributed to the direct or invasive effects of a malignancy. These syndromes are considered clinically important because they may provide early recognition, diagnosis, and management of the malignancy in a timely manner. Many of their presenting symptoms such as ectopic Cushing's syndrome, hypercalcemia of malignancy (HCM), syndrome of inappropriate secretion of antidiuretic hormone (SIADH), neurological dysfunctions, and paraneoplastic autoimmune thrombocytopenia overlap with those of nonneoplastic disorders, yet their pathogenesis and responses to treatment differ. Treatment for ectopic Cushing's syndrome due to a PNS consists of treatment of the underlying malignancy and its comorbidities. Drug therapies may include ketoconazole, mitotane, metyrapone, somatostatin analogs, and dopamine agonists. Hypercalcemia may be classified into cases with parathyroid hormone (PTH)-dependent causes or PTH-independent causes such as HCM, in which osteoclast inhibitors may be deployed. Treatments of PNS-mediated SIADH include treatment of the underlying malignancy and strategies to increase serum sodium levels. Amifampridine is now considered the first-line agent for paraneoplastic Lambert-Eaton myasthenic syndrome, whereas steroids, intravenous immune globulin, thrombopoietin receptor agonists (eg, romiplostim, eltrombopag, and avatrombopag), fostamatinib, and rituximab may find their niche in treatment of PNS-mediated autoimmune thrombocytopenia.

CONCLUSION

Supportive care for PNSs lends opportunities to pharmacists to add quality, value, and safety.

Overview of the 2022 WHO Classification of Neuroendocrine Neoplasms

In this review, we detail the changes and the relevant features that are applied to neuroendocrine neoplasms (NENs) in the 2022 WHO Classification of Endocrine and Neuroendocrine Tumors. Using a question-and-answer approach, we discuss the consolidation of the nomenclature that distinguishes neuronal paragangliomas from epithelial neoplasms, which are divided into well-differentiated neuroendocrine tumors (NETs) and poorly differentiated neuroendocrine carcinomas (NECs). The criteria for these distinctions based on differentiation are outlined. NETs are generally (but not always) graded as G1, G2, and G3 based on proliferation, whereas NECs are by definition high grade; the importance of Ki67 as a tool for classification and grading is emphasized. The clinical relevance of proper classification is explained, and the importance of hormonal function is examined, including eutopic and ectopic hormone production. The tools available to pathologists for accurate classification include the conventional biomarkers of neuroendocrine lineage and differentiation, INSM1, synaptophysin, chromogranins, and somatostatin receptors (SSTRs), but also include transcription factors that can identify the site of origin of a metastatic lesion of unknown primary site, as well as hormones, enzymes, and keratins that play a role in functional and structural correlation. The recognition of highly proliferative, well-differentiated NETs has resulted in the need for biomarkers that can distinguish these G3 NETs from NECs, including stains to determine expression of SSTRs and those that can indicate the unique molecular pathogenetic alterations that underlie the distinction, for example, global loss of RB and aberrant p53 in pancreatic NECs compared with loss of ATRX, DAXX, and menin in pancreatic NETs. Other differential diagnoses are discussed with recommendations for biomarkers that can assist in correct classification, including the distinctions between epithelial and non-epithelial NENs that have allowed reclassification of epithelial NETs in the spine, in the duodenum, and in the middle ear; the first two may be composite tumors with neuronal and glial elements, and as this feature is integral to the duodenal lesion, it is now classified as composite gangliocytoma/neuroma and neuroendocrine tumor (CoGNET). The many other aspects of differential diagnosis are detailed with recommendations for biomarkers that can distinguish NENs from non-neuroendocrine lesions that can mimic their morphology. The concepts of mixed neuroendocrine and non-neuroendocrine (MiNEN) and amphicrine tumors are clarified with information about how to approach such lesions in routine practice. Theranostic biomarkers that assist patient management are reviewed. Given the significant proportion of NENs that are associated with germline mutations that predispose to this disease, we explain the role of the pathologist in identifying precursor lesions and applying molecular immunohistochemistry to guide genetic testing.

Quantitative Analysis of Plasma Cell-Free DNA and Its DNA Integrity and Hypomethylation Status as Biomarkers for Tumor Burden and Disease Progression in Patients with Metastatic Neuroendocrine Neoplasias

Simple Summary

Neuroendocrine neoplasias (NEN) are a heterogeneous group of frequent slow-progressing malignant tumors for which a reliable marker for tumor relapse and progression is still lacking. Previously, circulating cell-free DNA and its global methylation status and fragmentation rate have been proposed to be valuable prognostic tumor markers in a variety of malignancies. In the current study, we compared plasma cell-free DNA (cfDNA) properties of NEN patients with a healthy control group and a group of surgically cured patients. Our results revealed significantly higher plasma cfDNA concentrations with increased fragmentation and hypomethylation in patients with advanced metastatic NEN, which was strongly associated with tumor load and could help to differentiate between metastasized disease and presumably cured patients. This suggests that the combined analysis of plasma cfDNA characteristics is a potent and sensitive prognostic and therapeutic biomarker for tumor burden and disease progression in patients with neuroendocrine neoplasias.

Abstract

Background: Neuroendocrine neoplasia (NEN) encompasses a diverse group of malignancies marked by histological heterogeneity and highly variable clinical outcomes. Apart from Chromogranin A, specific biomarkers predicting residual tumor disease, tumor burden, and disease progression in NEN are scant. Thus, there is a strong clinical need for new and minimally invasive biomarkers that allow for an evaluation of the prognosis, clinical course, and response to treatment of NEN patients, thereby helping implement individualized treatment decisions in this heterogeneous group of patients. In the current prospective study, we evaluated the role of plasma cell-free DNA concentration and its global hypomethylation and fragmentation as possible diagnostic and prognostic biomarkers in patients with neuroendocrine neoplasias. Methods: The plasma cfDNA concentration, cfDNA Alu hypomethylation, and LINE-1 cfDNA integrity were evaluated prospectively in 63 NEN patients with presumably cured or advanced metastatic disease. The cfDNA characteristics in NEN patients were compared to the results of a group of 29 healthy controls and correlated with clinical and histopathological data of the patients. Results: Patients with advanced NEN showed a significantly higher cfDNA concentration and percentage of Alu hypomethylation and a reduced LINE-1 cfDNA integrity as compared to the surgically cured NET patients and the healthy control group. The increased hypomethylation and concentration of cfDNA and the reduced cfDNA integrity in NEN patients were strongly associated with tumor burden and poor prognosis, while no correlation with tumor grading, differentiation, localization, or hormonal activity could be found. Multiparametric ROC analysis of plasma cfDNA characteristics was able to distinguish NEN patients with metastatic disease from the control group and the cured NEN patients with AUC values of 0.694 and 0.908, respectively. This was significant even for the group with only a low tumor burden. Conclusions: The present study, for the first time, demonstrates that the combination of plasma cfDNA concentration, global hypomethylation, and fragment length pattern has the potential to serve as a potent and sensitive prognostic and therapeutic “liquid biopsy” biomarker for tumor burden and disease progression in patients with neuroendocrine neoplasias.

Machine intelligence in non-invasive endocrine cancer diagnostics

Artificial intelligence (AI) has illuminated a clear path towards an evolving health-care system replete with enhanced precision and computing capabilities. Medical imaging analysis can be strengthened by machine learning as the multidimensional data generated by imaging naturally lends itself to hierarchical classification. In this Review, we describe the role of machine intelligence in image-based endocrine cancer diagnostics. We first provide a brief overview of AI and consider its intuitive incorporation into the clinical workflow. We then discuss how AI can be applied for the characterization of adrenal, pancreatic, pituitary and thyroid masses in order to support clinicians in their diagnostic interpretations. This Review also puts forth a number of key evaluation criteria for machine learning in medicine that physicians can use in their appraisals of these algorithms. We identify mitigation strategies to address ongoing challenges around data availability and model interpretability in the context of endocrine cancer diagnosis. Finally, we delve into frontiers in systems integration for AI, discussing automated pipelines and evolving computing platforms that leverage distributed, decentralized and quantum techniques.

A real-life treatment cohort of pancreatic neuroendocrine tumors: High-grade increase in metastases confers poor survival

BACKGROUND

Tumor grade determined by the Ki67 index is the best prognostic factor for pancreatic neuroendocrine tumors (PanNETs). However, we often observe that the grade of metastases differs from that of their primary tumors. This study aimed to investigate the frequency of grade changes between primary tumors and metastases, explore its association with clinical characteristics, and correlate the findings with the prognosis.

METHODS

Six hundred forty-eight patients with pancreatic neuroendocrine neoplasms treated at Fudan University Shanghai Cancer Center were screened for inclusion, and 103 patients with PanNETs who had paired primary tumors and metastases with an available Ki67 index were included. Re-evaluation of Ki67 was performed on 98 available samples from 69 patients.

RESULTS

Fifty cases (48.5%) had a Ki67 index variation, and 18 cases (17.5%) displayed a grade increase. Metachronous metastases showed significantly higher Ki67 index variation than synchronous metastases (P=0.028). Kaplan-Meier analyses showed that high-grade metastases compared to low-grade primary tumors were significantly associated with decreased progression-free survival (PFS, P=0.012) and overall survival (OS, P=0.027). Multivariable Cox regression analyses demonstrated that a low-grade increase to high-grade was an unfavorable and independent prognostic factor for PFS and OS (P=0.010, and P=0.041, respectively).

CONCLUSIONS

A high-grade increase in metastases was an unfavorable predictor of PanNETs, which emphasized the importance of accurate pathological grading and could provide a reference for clinical decision-making.

Cdk5 drives formation of heterogeneous pancreatic neuroendocrine tumors

Pancreatic neuroendocrine tumors (PanNETs) are a heterogeneous population of neoplasms that arise from hormone-secreting islet cells of the pancreas and have increased markedly in incidence over the past four decades. Non-functional PanNETs, which occur more frequently than hormone-secreting tumors, are often not diagnosed until later stages of tumor development and have poorer prognoses. Development of successful therapeutics for PanNETs has been slow, partially due to a lack of diverse animal models for pre-clinical testing. Here, we report development of an inducible, conditional mouse model of PanNETs by using a bi-transgenic system for regulated expression of the aberrant activator of Cdk5, p25, specifically in β-islet cells. This model produces a heterogeneous population of PanNETs that includes a subgroup of well-differentiated, non-functional tumors. Production of these tumors demonstrates the causative potential of aberrantly active Cdk5 for generation of PanNETs. Further, we show that human PanNETs express Cdk5 pathway components, are dependent on Cdk5 for growth, and share genetic and transcriptional overlap with the INS-p25OE model. The utility of this model is enhanced by the ability to form tumor-derived allografts. This new model of PanNETs will facilitate molecular delineation of Cdk5-dependent PanNETs and the development of new targeted therapeutics.

How does the pancreatic solid pseudopapillary neoplasm confuse us: Analyzing from the point view of MRI-based radiomics?

OBJECTIVES

To construct MRI-based radiomics logistic model in differentiating solid pseudopapillary neoplasm (SPN) from three differential diseases containing adenocarcinoma, neuroendocrine tumor (NET), and cystadenoma of pancreas.

MATERIALS AND METHODS

A total of 21 SPNs and 140 differential diseases were enrolled. The MRI images of T1WI, T2WI, DWI, and contrast-enhanced (CE) sequences were taken to delineate the volume of interest, and the corresponding radiomics features were calculated. After the preprocess of data balance and image standardize, the data was divided into training set (6 SPNs and 42 differential diseases) and validation set (15 SPNs and 98 differential diseases) with a proportion of 7:3, randomly. Then after feature selection, four MRI-based logistic models included T1WI, T2WI, DWI, CE, and sum logistic models (Log-T1WI, Log-T2WI, Log-DWI, Log-CE, and Log-sum) were established. The receiver operation curve (ROC) was depicted to evaluate the efficacy of each model.

RESULTS

To the single MRI sequence, the AUCs of Log-T1WI, Log-T2WI, Log-DWI, and Log-CE were similar. Seemingly the AUCs of Log-T2WI were slightly higher with 0. 876 (95%CI, 0.797-0.956) in the training set and 0.853 (95%CI, 0.708-0.998) in the validation set. The Log-sum of four MRI sequences displayed better differentiating efficiency, with AUCs of 0.929 (95%CI, 0.877-0.980) in the training set and 0.925 (95%CI, 0.845-1.000) in the validation set. The Log-Ra/Clin model combined clinical information and radiomics showed the highest AUC of 0.962 (95%CI, 0.919-0.985).

CONCLUSIONS

MRI-based radiomics analysis helped to discern SPNs from radiologically misdiagnosed adenocarcinoma, neuroendocrine tumor, and cystadenoma of pancreas. The efficacy of single sequence logistic model was similar. The Log-sum combined four sequences and Log-Ra/Clin combined clinical information and radiomics demonstrated the better performance in distinction.

Added Value of Tomoelastography for Characterization of Pancreatic Neuroendocrine Tumor Aggressiveness Based on Stiffness

Simple Summary

The prediction of pancreatic neuroendocrine tumor (PNET) aggressiveness is important for treatment planning. The aim of this study was to evaluate the diagnostic performance of magnetic resonance elastography (MRE) with tomoelastography postprocessing (tomoelastography) in differentiating PNET from healthy pancreatic tissue and to correlate PNET stiffness with aggressiveness using asphericity derived from positron emission tomography (PET) as reference. In this prospective study we showed in a group of 13 patients with PNET that tomoelastography detected PNET by increased stiffness (p < 0.01) with a high diagnostic performance (AUC = 0.96). PNET was positively correlated with PET derived asphericity (r = 0.81). Tomoelastography provides quantitative imaging markers for the detection of PNET and the prediction of greater tumor aggressiveness by increased stiffness.

Abstract

Purpose: To evaluate the diagnostic performance of tomoelastography in differentiating pancreatic neuroendocrine tumors (PNETs) from healthy pancreatic tissue and to assess the prediction of tumor aggressiveness by correlating PNET stiffness with PET derived asphericity. Methods: 13 patients with PNET were prospectively compared to 13 age-/sex-matched heathy volunteers (CTR). Multifrequency MR elastography was combined with tomoelastography-postprocessing to provide high-resolution maps of shear wave speed (SWS in m/s). SWS of pancreatic neuroendocrine tumor (PNET-T) were compared with nontumorous pancreatic tissue in patients with PNET (PNET-NT) and heathy pancreatic tissue (CTR). The diagnostic performance of tomoelastography was evaluated by ROC-AUC analysis. PNET-SWS correlations were calculated with Pearson’s r. Results: SWS was higher in PNET-T (2.02 ± 0.61 m/s) compared to PNET-NT (1.31 ± 0.18 m/s, p < 0.01) and CTR (1.26 ± 0.09 m/s, p < 0.01). An SWS-cutoff of 1.46 m/s distinguished PNET-T from PNET-NT (AUC = 0.89; sensitivity = 0.85; specificity = 0.92) and a cutoff of 1.49 m/s differentiated pancreatic tissue of CTR from PNET-T (AUC = 0.96; sensitivity = 0.92; specificity = 1.00). The SWS of PNET-T was positively correlated with PET derived asphericity (r = 0.81; p = 0.01). Conclusions: Tomoelastography provides quantitative imaging markers for the detection of PNET and the prediction of greater tumor aggressiveness by increased stiffness.

Targeting HDACs in Pancreatic Neuroendocrine Tumor Models

Compared to pancreatic adenocarcinoma (PDAC), pancreatic neuroendocrine tumors (PanNET) represent a rare and heterogeneous tumor entity. In addition to surgical resection, several therapeutic approaches, including biotherapy, targeted therapy or chemotherapy are applicable. However, primary or secondary resistance to current therapies is still challenging. Recent genome-wide sequencing efforts in PanNET identified a large number of mutations in pathways involved in epigenetic modulation, including acetylation. Therefore, targeting epigenetic modulators in neuroendocrine cells could represent a new therapeutic avenue. Detailed information on functional effects and affected signaling pathways upon epigenetic targeting in PanNETs, however, is missing. The primary human PanNET cells NT-3 and NT-18 as well as the murine insulinoma cell lines beta-TC-6 (mouse) and RIN-T3 (rat) were treated with the non-selective histone-deacetylase (HDAC) inhibitor panobinostat (PB) and analyzed for functional effects and affected signaling pathways by performing Western blot, FACS and qPCR analyses. Additionally, NanoString analysis of more than 500 potentially affected targets was performed. In vivo immunohistochemistry (IHC) analyses on tumor samples from xenografts and the transgenic neuroendocrine Rip1Tag2-mouse model were investigated. PB dose dependently induced cell cycle arrest and apoptosis in neuroendocrine cells in human and murine species. HDAC inhibition stimulated redifferentiation of human primary PanNET cells by increasing mRNA-expression of somatostatin receptors (SSTRs) and insulin production. In addition to hyperacetylation of known targets, PB mediated pleitropic effects via targeting genes involved in the cell cycle and modulation of the JAK2/STAT3 axis. The HDAC subtypes are expressed ubiquitously in the existing cell models and in human samples of metastatic PanNET. Our results uncover epigenetic HDAC modulation using PB as a promising new therapeutic avenue in PanNET, linking cell-cycle modulation and pathways such as JAK2/STAT3 to epigenetic targeting. Based on our data demonstrating a significant impact of HDAC inhibition in clinical relevant in vitro models, further validation in vivo is warranted.

Acquired hepatocerebral degeneration in a metastatic neuroendocrine tumor long-term survivor — an update on neuroendocrine neoplasm’s treatment: A case report

BACKGROUND

Metastatic small bowel low-grade neuroendocrine tumors (NETs) have a good prognosis. Surgery is the only curative treatment; however, this may induce advanced liver disease, particularly in long-term survivor patients. Acquired hepatocerebral degeneration or Parkinsonism in cirrhosis is characterized by rapidly progressive extrapyramidal symptoms in patients with advanced liver disease.

CASE SUMMARY

A 70-year-old man presented to the emergency department with diminished consciousness and disorientation, and was diagnosed with hepatic encephalopathy. The patient was diagnosed in 1993 with a metastatic small bowel NET, for which he twice underwent hepatic surgery, with metastatic resection in 1993 and a right hepatectomy in 2002 to remove two hepatic metastases. In 2003, the patient started first-line chemotherapy and in 2004 started the first of three consecutive biological treatments, followed by radio-molecular therapy, achieving stable disease for 14 years. Disease progression was identified and he underwent an endoscopic retrograde cholangiopancreatography. However, in 2019 advanced liver disease was identified. We diagnosed the development of acquired hepatocerebral degeneration, an unusual long-term side effect after multiple hepatic procedures.

CONCLUSION

The importance of regular and ongoing surveillance in long-term NET survivors who undergo hepatic procedures should be integrated into the therapeutic management plan, as some of these negative outcomes could be prevented.

Development and Validation of Novel Nomograms Using Serum Tumor Markers for the Prediction of Preoperative Histologic Grades in Gastroenteropancreatic Neuroendocrine Tumors

Background

To develop and validate nomogram models for the preoperatively prediction of the histologic grade of gastroenteropancreatic neuroendocrine tumors (GEP-NETs) to provide appropriate treatments.

Methods

A total of 1014 participants, including 211 healthy controls, 293 patients with benign diseases, 299 patients with cancers, and 211 patients with GEP-NETs were included in the final analysis. Their sociodemographic and laboratory information, including serum tumor markers such as AFP, CEA, CA19-9, CA72-4, Cyfra21-1 and NSE were collected. Nomogram models were developed to preoperatively predict histologic grades of GEP-NETs.

Results

Among six serum tumor markers, only NSE was found to have a statistically significant association with the histologic grades in GEP-NETs (G1 vs. G2: p < 0.05; G2 vs. G3: p < 0.001; G1 vs. G3: p < 0.0001), which was combined with sex and age to develop the nomogram models. The first nomogram (to differentiate grade 1(G1) and grade 2/3 tumor (G2/G3)) showed a strong association to differentiate with an AUC of 0.747 (95% CI: 0.663-0.832) and 0.735 (95% CI: 0.624-0.847) in the training and validation datasets, respectively. The second nomogram (to differentiate G1/G2 and G3 tumors) showed a strong association to differentiate with an AUC of 0.827 (95% CI: 0.744-0.911) and 0.847 (95% CI: 0.744-0.950) in the training and validation datasets, respectively. The ROC, area under ROC curve (AUC), calibration curve and decision curve analysis (DCA) demonstrated the clinical usefulness of both models.

Conclusions

We proposed two novel nomogram models based on sex, age and serum NSE levels to preoperatively predict the histologic grades in GEP-NETs to assist the clinical decision-making.

Neuroendocrine Carcinomas with Atypical Proliferation Index and Clinical Behavior: A Systematic Review

BACKGROUND

Highly proliferative (G3) neuroendocrine neoplasms are divided into well differentiated tumors (NETs) and poorly differentiated carcinomas (NECs), based on the morphological appearance. This systematic review aims to evaluate the clinicopathological features and the treatment response of the NEC subgroup with a Ki67 labeling index (LI) < 55%.

METHODS

A literature search was performed using MEDLINE, Cochrane Library, and Scopus between December 2019 and April 2020, last update in October 2020. We included studies reporting data on the clinicopathological characteristics, survival, and/or therapy efficacy of patients with NECs, in which the Ki67 LI was specified.

RESULTS

8 papers were included, on a total of 268 NEC affected patients. NECs with a Ki67 LI < 55% have been reported in patients of both sexes, mainly of sixth decade, pancreatic origin, and large-cell morphology. The prevalent treatment choice was chemotherapy, followed by surgery and, in only one study, peptide receptor radionuclide therapy. The subgroup of patients with NEC with a Ki67 LI < 55% showed longer overall survival and progression free survival and higher response rates than the subgroup of patients with a tumor with higher Ki67 LI (≥55%).

CONCLUSIONS

NECs are heterogeneous tumors. The subgroup with a Ki67 LI < 55% has a better prognosis and should be treated and monitored differently from NECs with a Ki67 LI ≥ 55%.

Cardiac Metastases in Patients with Neuroendocrine Tumours: Clinical Features, Therapy Outcomes, and Prognostic Implications

BACKGROUND

Cardiac metastases (CM) from neuroendocrine tumours (NET) are rare; however, with the introduction of new molecular imaging modalities, such as 68Ga-DOTATATE PET-CT for NET diagnosis and re-staging, they are now identified more frequently. This study presents a single-institution experience on the NET CM characteristics, management, and prognostic implications.

METHODS

Between January 1998 and January 2020, 25 NET patients with CM were treated in our unit. A retrospective review of electronic records was performed. Overall survival (OS) was assessed by the Kaplan-Meier method. Cox regression models were used to evaluate the association of various clinical variables with OS.

RESULTS

The median age in the NET CM cohort was 64 years, with small intestine being the most common primary (84%). Nearly half of the patients suffered either from shortness of breath (48%) or had palpitations (12%). Peptide receptor radionuclide therapy (PRRT) was applied in more than half of the patients (64%), who had an improved trend for a longer median OS compared to those patients who did not receive PRRT (76.0 vs. 14.0 months, p = 0.196). The multivariate analysis demonstrated that concomitant skeletal or pancreatic metastases, as well as N-terminal pro-B-type natriuretic peptide (NT pro-BNP) >2 × upper limit of normal (ULN), were independent poor prognosticators.

CONCLUSIONS

Clinical features of NET CM ranged from asymptomatic patients to heart failure. Concomitant bone or pancreatic metastases and NT pro-BNP levels >2 ULN predicted shorter survival time. PRRT serves as a feasible therapy with promising survival benefits; however, more data are needed.

Neuroendocrine Tumor Omic Gene Cluster Analysis Amplifies the Prognostic Accuracy of the NETest

BACKGROUND

The NETest is a multigene assay comprising 51 circulating neuroendocrine tumor (NET)-specific transcripts. The quotient of the 51-gene assay is based upon an ensemble of machine learning algorithms. Eight cancer hallmarks or "omes" (apoptome, epigenome, growth factor signalome, metabolome, proliferome, plurome, secretome, SSTRome) represent 29 genes. The NETest is an accurate diagnostic (>90%) test, but its prognostic utility has not been assessed. In this study, we describe the expansion of the NETest omic cluster components and demonstrate that integration amplifies NETest prognostic accuracy.

METHODS

Group 1: n = 222; including stable disease (SD, n = 146), progressive disease (PD, n = 76), and controls (n = 139). Group 2: NET Registry NCT02270567; n = 88; prospective samples (SD, n = 54; PD, n = 34) with up to 24 months follow-up. We used PubMed literature review, interactomic analysis, nonparametric testing, Kaplan-Meier survival curves, and χ2 analyses to inform and define the prognostic significance of NET genomic "hallmarks."

RESULTS

2020 analyses: In-depth analyses of 47 -NETest genes identified a further six omes: fibrosome, inflammasome, metastasome, NEDome, neurome, and TFome. Group 1 analysis: Twelve omes, excluding the inflammasome and apoptome, were significantly (p < 0.05, 2.1- to 8.2-fold) elevated compared to controls. In the PD group, seven omes (proliferome, NEDome, epigenome, SSTRome, neurome, metastasome, and fibrosome) were elevated (both expression levels and fold change >2) versus SD. Group 2 analysis: All these seven omes were upregulated. In PD, they were significantly more elevated (p < 0.02) than in SD. The septet omic expression exhibited a 69% prognostic accuracy. The NETest alone was 70.5% accurate. A low NETest (≤40) integrated with epigenome/metastasome levels was an accurate prognostic for PD (90%). A high NETest (>40) including the fibrosome/NEDome predicted PD development within 3 months (100%). Using decision tree analysis to integrate the four omes (epigenome, metastasome, fibrosome, and NEDome) with the NETest score generated an overall prognostic accuracy of 93%.

CONCLUSIONS

Examination of NETest omic gene cluster analysis identified five additional clinically relevant cancer hallmarks. Identification of seven omic clusters (septet) provides a molecular pathological signature of disease progression. The integration of the quartet (epigenome, fibrosome, metastasome, NEDome) and the NETest score yielded a 93% accuracy in the prediction of future disease status.

Chromogranin A: A Valuable Serum Diagnostic Marker for Non-Insulinoma Neuroendocrine Tumors of the Pancreas in a Chinese Population

Background

Pancreatic neuroendocrine tumors (P-NETs) are uncommon neoplasms, with few studies to date assessing serum biomarkers for the diagnosis of P-NETs. This study assessed the ability of serum chromogranin A (CgA) concentrations to distinguish P-NETs from other pancreatic lesions in a Chinese population and to determine the histological grades of P-NETs.

Material/Methods

This prospective study enrolled 165 patients, including 73 with proven P-NETs, 60 with malignant tumors of the pancreas, and 32 with benign lesions of the pancreas. Serum CgA concentrations were measured by ELISA.

Results

Serum CgA concentrations were significantly higher in patients with P-NET than in patients with other pancreatic malignancies and benign lesions (P<0.001), but did not differ significantly in the latter 2 groups (P=0.827). Serum CgA concentrations were significantly higher in patients with non-insulinoma P-NETs than in the other groups (P<0.001), but did not differ significantly in patients with insulinoma and patients with non-P-NETs (P=0.668). Receiver operating characteristic (ROC) curves revealed that a serum CgA concentration of 77.8 ng/ml could distinguish patients with non-insulinoma P-NETs from patients with non-P-NETs, with a sensitivity of 96.7%, a specificity of 76.1%, and an area under the ROC curve of 0.897. In patients with P-NETs, multifactor analysis showed that the non-insulinoma subtype and the presence of liver metastases were associated with elevated serum CgA (both p<0.001).

Conclusions

Serum CgA concentration may be a valuable diagnostic biomarker for non-insulinoma P-NETs. Elevated serum CgA is likely associated with liver metastases.

Neuroendocrine neoplasia of the gastrointestinal tract revisited: towards precision medicine

Over the past 5 years, a number of notable research advances have been made in the field of neuroendocrine cancer, specifically with regard to neuroendocrine cancer of the gastrointestinal tract. The aim of this Review is to provide an update on current knowledge that has proven effective for the clinical management of patients with these tumours. For example, for the first time in the tubular gastrointestinal tract, well-differentiated high-grade (grade 3) tumours and mixed neuroendocrine-non-neuroendocrine neoplasms (MiNENs) are defined in the WHO classification. This novel classification enables efficient identification of the most aggressive well-differentiated neuroendocrine tumours and helps in defining the degree of aggressiveness of MiNENs. The Review also discusses updates to epidemiology, cell biology (including vesicle-specific components) and the as-yet-unresolved complex genetic background that varies according to site and differentiation status. The Review summarizes novel diagnostic instruments, including molecules associated with the secretory machinery, novel radiological approaches (including pattern recognition techniques), novel PET tracers and liquid biopsy combined with DNA or RNA assays. Surgery remains the treatment mainstay; however, peptide receptor radionuclide therapy with novel radioligands and new emerging medical therapies (including vaccination and immunotherapy) are evolving and being tested in clinical trials, which are summarized and critically reviewed here.

Assessment and State of Nutrition of Patients with Gastroenteropancreatic Neuroendocrine Neoplasms

Introduction: In recent decades, the number of gastro-entero-pancreatic neuroendocrine neoplasms (GEP-NENs) cases, associated with coexisting metabolic disorders, has been continuously increasing. Patients with progressing neoplastic disease are at a risk of malnutrition. To improve the quality of life of neuroendocrine neoplasms (NEN) patients, the therapeutic approach should be supported by a well-balanced diet. The aim of the study was to analyze the nutritional errors and deficits in a group of GEP-NET patients. Materials and methods: The study group included 26 GEP-NET patients; 13 men and 13 women. The mean age of women was 68.77 ± 8.0, and the mean age of men was 64.69 ± 8.1. Three interviews on consumption in the last 24 h were performed, in order to evaluate the quality and quantity of nutrition. The data was incorporated into a dietetics software, which allows one to calculate the number of over 58 micronutrients and macronutrients with the participation of 52 menus. Subsequently, the mean values were compared with the current nutritional standards. Results: An energy deficit was observed in the group of women—76.9%, and men—100%, as well as high fat consumption in 23.1% in both groups. The proportions of SFA/MUFA/PUFA were very negative, whereas the consumption of saccharose was too high. Vitamin D deficiency was observed in 100% of men and women. Moreover, both men and women experienced the deficiency of vitamin E, folates and niacin. The consumption of sodium and phosphorus was twice as high as recommended, and an insufficient supply of calcium was observed in 80% of women and 90% of men. The insufficient consumption of magnesium, iodine and potassium in a significant part of the studied group was observed. All participants consumed too much cholesterol and insufficient amounts of fiber. The healthy diet indicator (HDI) and diet quality index (DQI) scores were 3.1 ± 1.8 (HDI) and 3.7 ± 1.6 (DQI) for women, and 7.2 ± 2.6 (HDI) and 8.5 ± 2.4 (DQI) for men. Conclusions: When analyzing the nutrition of GEP-NET patients, we highlight that they do not have a proper diet, despite the fact that they changed the way they eat. Dietetics support and the development of official nutritional standards seem to be a necessary element in the therapy of GEP-NET patients.

CD56 Expression Is Associated with Biological Behavior of Pancreatic Neuroendocrine Neoplasms

Purpose

CD56 is a neural cell adhesion molecule that plays a role in the cohesiveness of neuroendocrine cells. The aim of this study was to explore the biological values of CD56 expression in pancreatic neuroendocrine neoplasms (PNENs) and its role in predicting PNENs grades.

Patients and Methods

A total of 138 patients with histological-proven PNENs was included (66 G1, 46 G2 and 26 G3). The clinicopathological characteristics, including mitosis count, ki67 index, chromogranin A (CgA), synaptophysin (Syn) and CD56 expression, were evaluated. We assessed the diagnostic performance of markers in predicting PNEN G3 and the association between CD56 expression and risk of G3 or organs invasion.

Results

Lack of CD56 immunoreaction (CD56-) was more common in PNEN G3 than G1/G2 (31% vs 0–2%, p < 0.01). The sizes of CD56- tumors were larger than CD56 positive tumors in PNEN G3 (p < 0.01). The odds ratio (OR) of CD56- expression was 13.6 [95% confidence interval (CI): 2.1–88.1] in predicting PNEN G3. The OR of CD56- expression was 6.5 (95% CI: 1.1–38.6) and 31.9 (95% CI: 1.09–938.3) in predicting organs invasion and neuroendocrine carcinoma in PNEN G3, respectively. Tumor size (area under the curve [AUC] = 0.77 and size+CD56- expression [AUC = 0.84]) had acceptable performance in predicating PNEN G3.

Conclusion

Lack of CD56 immunoreaction may be a predictor and biological behavior marker for PNEN G3.

The Neuroendocrine Neoplasms of the Digestive Tract: Diagnosis, Treatment and Nutrition

Nuroendocrine neoplasms (NENs) are a group of rare neoplasms originating from dispersed neuroendocrine cells, mainly of the digestive and respiratory tract, showing characteristic histology and immunoprofile contributing to classification of NENs. Some NENs have the ability to produce biogenic amines and peptide hormones, which may be associated with clinical syndromes like, e.g., the carcinoid syndrome caused by unmetabolized overproduced serotonin, hypoglycemic syndrome in case of insulinoma, or Zollinger-Ellison syndrome accompanying gastrinoma. Diagnostics for these include ultrasound with endoscopic ultrasound (EUS), computed tomography (CT), magnetic resonance imaging (MRI), and positron-emission tomography/computed tomography (PET/CT). Different nuclear medicine procedures can also be used, like somatostatin analogues scintigraphy (SRS) and 68Ga-Dota-Peptide PET/CT, as well as biochemical methods to determine the level of general neuroendocrine markers, such as chromogranin A (CgA), 5-hydroxyindolacetic acid (5-HIAA), synaptopfysin and cell type-specific peptide hormones, and neurotransmitters like gastrin, insulin, serotonin, and histamine. NENs influence the whole organism by modulating metabolism. The treatment options for neuroendocrine neoplasms include surgery, somatostatin analogue therapy, radionuclide therapy, chemotherapy, molecular targeted therapies, alpha-interferon therapy, and inhibitors of serotonin production. In the case of hypersensitivity to biogenic amines, a diet that limits the main sources of amines should be used. The symptoms are usually connected with histamine, tyramine and putrescine. Exogenic sources of histamine are products that take a long time to mature and ferment. Patients with a genetic insufficiency of the diamine oxidase enzyme (DAO), and those that take medicine belonging to the group of monoamine oxidases (MAO), are particularly susceptible to the negative effects of amines. Diet plays an important role in the initiation, promotion, and progression of cancers. As a result of the illness, the consumption of some nutrients can be reduced, leading to nutritional deficiencies and resulting in malnutrition. Changes in metabolism may lead to cachexia in some patients suffering from NENs. The aim of this narrative review was to advance the knowledge in this area, and to determine possibilities related to dietary support. The authors also paid attention to role of biogenic amines in the treatment of patients with NENs. We can use this information to better understand nutritional issues faced by patients with gastroenteropancreatic neuroendocrine neoplasms (GEP-NENs), and to help inform the development of screening tools and clinical practice guidelines.

Prognostic value of the 2017 World Health Organization Classification System for gastric neuroendocrine tumors: A single-center experience

BACKGROUND/AIMS

Gastric neuroendocrine tumors (G-NETs) are rare tumors, but their incidence is gradually increasing. Despite the existence of many classification systems, determining prognosis and planning treatment in patients with G-NETs remains a clinical challenge. In this study, the prognostic value of the World Health Organization (WHO) 2017 grading system and the effect of surgery on survival in low grade neuroendocrine tumors were investigated.

MATERIALS AND METHODS

G-NETs who were diagnosed between January 2000 and May 2017 were included in the study. Patients' demographic characteristics, treatment details, and survival data were obtained from medical charts. Pathological samples were re-classified according to the WHO 2017 grading system.

RESULTS

Of the total 94 evaluated patients, 50 (53.2%) were classified with G1 NETs, 37(39.4%) with G2 NETs, 4(4.2%) with well-differentiated G3 NETs, and the remaining 3 patients with poorly differentiated G3 neuroendocrine carcinoma (NEC). The median follow-up time was 83.2 months. There was a statistically significant difference in 5-year progression free survival (PFS) between G1 tumors (100%) and G2 tumors (76%) (p<0.001). However, there was no statistically significant deference in 5-year overall survival rate (OS) for G1 (97%) and G2 (82%) tumors (p=0.141). When G2 and G1 NETs were compared according to their surgical approach, radical surgery was more frequently performed in patients with G2 tumors (p<0.001). However, radical surgery did not improve PFS in G1 and G2 NETs.

CONCLUSION

The WHO 2017 NET classification system may have low prognostic value for determining the prognosis of patients with G1 and G2 tumors. Radical surgery for G1 and G2 NETs did not improve PFS in our study.

Differential Diagnosis of Nonhypervascular Pancreatic Neuroendocrine Neoplasms From Pancreatic Ductal Adenocarcinomas, Based on Computed Tomography Radiological Features and Texture Analysis

RATIONALE AND OBJECTIVES

To determine computed tomography (CT) radiological features and texture features that are rewarding in differentiating nonhypervascular pancreatic neuroendocrine neoplasms (PNENs) from pancreatic ductal adenocarcinomas (PDACs).

MATERIALS AND METHODS

We compared patients to pathologically proven nonhypervascular PNENs and age-matched controls with pathologically proven PDACs in a 1:2 ratio. Preoperative CT images in the arterial phase (AP) and portal vein phase (PVP) were obtained. Two radiologists independently reviewed the morphological characteristics of each tumor. Three-dimensional regions of interest (ROIs), drawn using ITK-SNAP software, were input into AK software (Artificial Intelligent Kit, GE) to extract texture features from AP and PVP images. Differences between PNENs and PDACs were analyzed with the chi-squared test, least absolute shrinkage and selection operator, kappa statistics, and uni- and multivariate logistic regression analyses.

RESULTS

In total, 40 nonhypervascular PNENs and 80 PDACs were evaluated. Maximum diameter on axial section, margin, calcification, vascularity in the tumor, and tumor heterogeneity were significantly different between PDACs and nonhypervascular PNENs. Multivariate analysis showed well-defined tumor margin (odds ratio: 21.0) and presence of calcification (odds ratio: 4.4) were significant predictors of nonhypervascular PNENs. The area under the receiver operating characteristic curve of the radiological feature model, AP texture model, and PVP texture model were 0.780, 0.855, and 0.929, respectively, based on logistic regression.

CONCLUSION

A well-defined margin and calcification in the tumor were helpful in discriminating nonhypervascular PNENs from PDACs. Texture analysis of contrast-enhanced CT images could be beneficial in differentially diagnosing nonhypervascular PNENs and PDACs.

Immune Checkpoint Markers in Neuroendocrine Carcinoma of the Digestive System

Digestive system neuroendocrine carcinomas (NECs) are rare neoplasms originating from neuroendocrine cells with a poor prognosis and limited effective treatments. Programmed cell death protein 1/ligand 1 (PD-1/PD-L1) blockade has been used in the management of more than 10 solid tumors and has achieved promising clinical outcomes. PD-L1 expression, immune cell infiltration, tumor mutational burden (TMB), and microsatellite instability (MSI) are all verified biomarkers that can predict the response to anti-PD-1/PD-L1 therapy. Here, we investigated PD-L1 expression and immune cell infiltration density by immunohistochemical (IHC) staining of tumor samples from 33 patients with digestive system NECs. Tumor and paratumor normal samples from 31 of these patients underwent whole-exome sequencing to evaluate TMB and the MSI-high (MSI-H) status. In total, 29.0% of digestive system NECs had positive PD-L1 expression according to the tumor proportion score (TPS). Infiltration of CD3⁺, CD8⁺, and CD68⁺ cells was observed in 69.7, 27.3, and 54.5% of patients, respectively. The TMB value for patients sequenced ranged from 0.57 to 11.75 mutations/Mb, with a median of 5.68 mutations/Mb. mSINGS, MSIsensor, and MSIseq were used to analyze the MSI status according to the sequencing data, and in our evaluation, no MSI-H status was detected. Our data might indicate a limited potential of anti-PD-1/PD-L1 monotherapy in digestive system NECs, although clinical trials are warranted.

Development and Validation of a Prognostic Nomogram to Guide Decision-Making for High-Grade Digestive Neuroendocrine Neoplasms

BACKGROUND

The objective of this study was to develop and validate a nomogram to predict 1-year overall survival (OS) and 2-year OS in patients with high-grade digestive neuroendocrine neoplasms (NENs) as well as to guide selection of subgroups that could benefit from systemic chemotherapy.

SUBJECTS, MATERIALS, AND METHODS

We performed a retrospective analysis of 223 patients with NENs of the gut and hepato-biliary-pancreatic system from four centers included in the development cohort. The nomogram was externally validated in a cohort of 90 patients from another one.

RESULTS

The final model included lactate dehydrogenase, performance status, stage, Ki67, and site of primary tumor, all of which had a significant effect on OS. The uncorrected C-index was 0.761 for OS, and the bias-corrected C-index was 0.744. Predictions correlated well with observed 1-year and 2-year outcomes (judged by eye). The area under the time-dependent receiver operating characteristic curve at 12 months and 24 months was 0.876 and 0.838, respectively. The nomogram performed well in terms of both discrimination and calibration when applied to the validation cohort, and OS was significantly different between the two groups classified by nomogram score (log-rank p < .001).

CONCLUSION

The validated nomogram provided useful prediction of OS, which can be offered for clinicians to improve their abilities to assess patient prognosis, to create clinical risk groups for informing treatment or for patient stratification by disease severity in clinical trials.

IMPLICATIONS FOR PRACTICE

The high-grade neuroendocrine neoplasms of the digestive system are rare malignancies with great heterogeneity. An overall survival nomogram was developed and externally validated in this study. Two subgroups were classified by the nomogram score, and platinum-based chemotherapy may not bring clinical benefit for the low-risk patients.

Is There a Role for Surgery in Patients with Neuroendocrine Tumors of the Esophagus? A Contemporary View from the NCDB

BACKGROUND

Esophageal neuroendocrine tumors (eNETs) are exceedingly rare, aggressive and have a poor prognosis. Treatment guidelines are ill-defined and mainly based on evidence from case reports and analogous experiences drawn from similar disease sites.

METHODS

The NCDB was reviewed for histologically confirmed stage I-III, primary eNETs from 2006 to 2014. Patients were grouped into whether or not they underwent primary tumor resection. Univariate, multivariable, and full bipartite propensity score (PS) adjusted Cox regression analyses were used to assess overall and relative survival differences.

RESULTS

A total of 250 patients were identified. Mean age was 65.0 (standard deviation [SD] 11.9) years, and 174 (69.6%) patients were male. Most patients had stage III disease (n = 136, 54.4%), and the most common type of NET was small cell eNET (n = 111, 44.4%). Chemotherapy was used in 186 (74.4%), radiation therapy in 178 (71.2%), and oncological resection was performed in 69 (27.6%) patients. Crude 2-year survival rates were higher in the operated (57.3%) compared with the nonoperated group (35.2%; p < 0.001). The survival benefit held true after multivariable adjustment (hazard ratio [HR] 0.47, 95% confidence interval [CI] 0.32-0.69, p < 0.001). After full bipartite PS adjustment analysis, survival was longer for patients who received a surgical resection compared with those who did not (HR 0.48, 95% CI 0.31-0.75, p = 0.003) with a corresponding 2-year overall survival rate of 63.3% (95% CI 52.0-77.2) versus 38.8% (95% CI 30.9-48.8), respectively.

CONCLUSIONS

Multimodal treatment that includes surgery is associated with better overall survival for eNETs. Additional research is needed to more definitively identify patients who benefit from esophagectomy and to establish an appropriate treatment algorithm.

Small-cell neuroendocrine carcinoma of the ileum: case report and literature review

Background

Poorly differentiated neuroendocrine carcinomas (NECs) originating from the gastrointestinal (GI) tract are rare and very highly malignant disease with a poor prognosis. Poorly differentiated NECs most commonly arise in the esophagus and the large bowel; however, they may occur within virtually any portion of the GI tract. It is known, however, that they do not typically occur in the small intestine.

Case report

A 21-year-old woman visited an emergency room with acute abdominal pain that commenced 2 days prior to her presentation. Thereafter, a computed tomography (CT) scan was notable for a small-intestine perforation, and huge masses were observed in the small intestine and the mesentery. The mass that was located at the ileum site is approximately 100 cm above the ileocecal (IC) valve, and while it is located on the anti-mesenteric border and it seems that luminal narrowing had occurred, an obstruction is absent. Also, a same-nature mass is on the mesentery. The pathologic reports confirmed a small-cell-type NEC with a mass size of 7.5 × 6.5 cm. The mitotic count is up to 24/10 high-power fields (HPFs), the results of the immunohistochemical stain are positive for CD56 and synaptophysin, and the Ki-67 level is 50%. %. After the operation, she was treated with Etoposide-Cisplatin (EP) chemotheraphy. Stable disease was seen during Etoposide-Cisplatin chemotheraphy. Liver metastasis was also confirmed after chemotheraphy. Additionally, Irinotecan and cisplatin were used for 3 cycles, but progression of disease, neutropenic fever, thrombocytopenia, general weakness persisted. Eventually, she died 1 year and 6 months after surgery.

Conclusion

Ileum-located NECs are diagnosed very rarely. The most common locations for these tumors along the GI tract are the esophagus and the large intestine, but they can arise anywhere. The prognosis for NECs is poor due to the metastatic disease of most patients at the time of diagnosis. The role of adjuvant treatment requires further evaluation for the attainment of a better understanding of the overall treatment effect.

Therapeutic index of lymphadenectomy among patients with pancreatic neuroendocrine tumors: A multi‐institutional analysis

BACKGROUND

The benefit derived from lymph node dissection (LND) in patients with pancreatic neuroendocrine tumors (pNETs) based on clinicopathological characteristics remains unclear.

METHODS

Patients undergoing surgery for pNET between 1997 and 2016 were identified using a multi-institutional dataset. The therapeutic index of LND relative to patient characteristics was calculated.

RESULTS

Among 647 patients, the median number of lymph nodes (LNs) evaluated was 10 (interquartile range: 4-16) and approximately one quarter of patients had lymph node metastasis (LNM) (N = 159, 24.6%). Among patients with LNM, 5-year recurrence-free survival was 56.0%, reflecting a therapeutic index value of 13.8. The therapeutic index was highest among patients with a moderately/poorly-differentiated pNET (21.5), Ki-67 ≥ 3% (20.1), tumor size ≥2.0 cm (20.0), and tumor location at the head of the pancreas (20.0). Patients with ≥8 LNs evaluated had a higher therapeutic index than patients who had 1 to 7 LNs evaluated (≥8: 17.9 vs 1-7: 7.5; difference of index: 11.4).

CONCLUSION

LND was mostly beneficial among patients with pNETs >2 cm, Ki-67 ≥ 3%, and lesions located at the pancreatic head as identification of LNM was most common among individuals with these tumor characteristics. Evaluation of ≥8 LNs was associated with a higher likelihood of identifying LNM as well as a higher therapeutic index, and therefore this number of LNs should be considered the goal.

[Neuroendocrine neoplasms : Two families with distinct features unified in one classification (German version)]

All neuroendocrine neoplasms (NENs) are characterized by the expression of synaptophysin and chromogranin A (or B). Yet, they are not a homogeneous group of tumors. Paradigmatic for these tumors are the NENs of the gastroenteropancreatic (GEP) system. Two NEN families can be distinguished: predominantly well differentiated and low-proliferative NENs, called neuroendocrine tumors (NET), and poorly differentiated and high-proliferative NENs, called neuroendocrine carcinomas (NECs). Based on their proliferative activity, GEP NETs are further classified into G1, G2, and G3 tumors. NECs are per definition G3 carcinomas. The morphological NEN dichotomy is supported by differences in epidemiology, genetics, clinics, and prognosis, and potentially has its cause originating from different progenitor cells. Genetically, NECs are distinguished by TP53 and RB1 alterations, which are lacking in NETs and are helpful in the distinction of NETs from NECs. Comparison of the GEP NEN WHO classification with extragastroenteropancreatic NEN classifications commonly reveal differences in terminology and categorization. In addition, they lack a grading system. However, common to all NEN classifications is the recognition of two tumor families differing in histological differentiation and prognosis. This allows the construction of a uniform classification frame for all NENs.

Clinical characteristics of early neuroendocrine carcinoma in stomach: A case report and review of literature

INTRODUCTION

Gastric neuroendocrine carcinoma (NEC) is rare. It is considered to be aggressive and has a poor prognosis since the diagnosis is usually made at its advanced stage. However, the survival rate is increased in some early gastric NECs. This study showed a case and reviewed the clinical characteristics of early NECs in stomach.

PATIENT CONCERNS

A 38-year-old man displayed no symptoms and underwent the gastric endoscopy test for his health examination, which showed a red slightly depressed lesion 1.0 cm in size on the lesser curvature of gastric cardia. Magnifying endoscopy with narrow-band imaging (NBI) revealed a clear demarcation and an irregular mesh in vessels within the depressed area. The background mucosa was negative for atrophic gastritis and Helicobacter Pylori infection. A contrast-enhanced computed tomography (CT) scan disclosed no obvious thickening of stomach and lymphadenopathy. Blood tests and physical examination were unremarkable. He had not received any surgical treatment and denied a family history of cancer and any genetic disorders. The pathologic result of biopsy from the lesion was suspicious of superficial carcinoma. Then endoscopic submucosal dissection (ESD) was performed.

DIAGNOSIS

Gastric NEC G3 in the early stage (T1aN0M0).

INTERVENTIONS

Concerning this patient's situation, we considered the ESD as a curable treatment. And no radical surgery or adjuvant chemotherapy was arranged.

OUTCOMES

The patient is doing well and displays no recurrence for 11 months, who is still in follow-up.

LESSONS SUBSECTIONS AS PER STYLE

The early diagnosis and effective treatment by endoscopy would contribute to improve the prognosis of gastric NECs.

Pancreatic neuroendocrine tumor: review of heterogeneous spectrum of CT appearance

OBJECTIVE

Pancreatic neuroendocrine tumors (PanNETs) are uncommon pancreatic neoplasms and can be a diagnostic challenge with heterogeneous spectrum of CT appearance. We review CT findings of PanNETs and other mimics.

CONCLUSION

PanNETs are typically hypervascular and have avid enhancement on arterial and venous phase images. However, dedicated pancreas protocol may be needed due to their sometimes atypical appearance including transient enhancement. Careful evaluation of CT findings will help differentiate PanNETs from their mimics, and can be used to establish the diagnosis of a PanNETs. Although an accurate diagnosis can be based on serological, urine, and CT scan findings, confirmation is made via pathological examination.

The Role of Surgery in Treating Resectable Limited Disease of Esophageal Neuroendocrine Carcinoma

BACKGROUND

Esophageal neuroendocrine carcinoma (NEC) is a rare malignant tumor. The role of surgery in resectable limited disease of esophageal NEC remains unclear. How to select a specific group of limited disease of esophageal NEC who might benefit from surgery remains to be answered.

METHODS

Patients undergoing esophagectomy for resectable limited disease of esophageal NEC in our department from January 2007 to June 2015 were analyzed. TNM staging system was applied to describe those patients, and according to their different long-term prognosis after surgery, those patients were subgrouped into surgery response limited disease (SRLD) group and surgery non-response limited disease (SNRLD) group. Both univariate and multivariate analyses were applied to identify potential prognostic factors.

RESULTS

A total of 72 patients with resectable limited disease of esophageal NEC were identified for analysis. The median survival time of those patients was 21.5 months. There was no significant survival differences among stage I, stage IIA, and stage IIB patients, but all these patients had significantly longer survival than stage III patients. Therefore, stage I, stage IIA, and stage IIB patients were aggregated together as SRLD group, and stage III patients were aggregated as SNRLD group. SRLD patients obtained significantly longer survival than SNRLD patients in both univariate analysis and multivariate analysis. Moreover, adjuvant therapy could significantly benefit SRLD patients (P = 0.004) but could not benefit SNRLD patients (P = 0.136).

CONCLUSIONS

Different responses to surgery existed in resectable limited disease of esophageal NEC indicating the need of further subgrouping for those patients. The resectable limited disease of esophageal NEC could be further subgrouped into SRLD group and SNRLD group according to the TNM staging system.

The New World Health Organization Classification for Pancreatic Neuroendocrine Neoplasia

Based on the 2010 version, the 2017 World Health Organization (WHO 2017) classification is for pancreatic neuroendocrine neoplasms (PanNEN). The WHO 2017 classification introduces the novel well-differentiated neuroendocrine tumor of high grade (NET G3). A sharp distinction between NET and poorly differentiated neuroendocrine carcinoma (NEC) is emphasized to highlight substantial biological differences. Further changes comprise the definition of mixed neuroendocrine non-neuroendocrine neoplasm (MiNEN), to accommodate all grades of both neoplasm components, and the abolition of preneoplastic lesions given their rarity in the pancreas. The 2017 American Joint Cancer Committee classification (AJCC 2017) adopts such a classification for all digestive sites.

Preoperative 68Ga-DOTA-Somatostatin Analog-PET/CT Hybrid Imaging Increases Detection Rate of Intra-abdominal Small Intestinal Neuroendocrine Tumor Lesions

Background

Small intestinal neuroendocrine tumors (SI-NETs) are the most common form of neoplasm in the small bowel. Radiological identification of primary tumors (PT), which may be multiple, is difficult, and therefore palpation of the entire small bowel is routinely performed during laparotomy. The aim was to determine detection rates of PT and peritoneal carcinomatosis (PC) with ⁶⁸Ga-DOTATOC/TATE-PET/CT in comparison with i.v. contrast-enhanced computed tomography (CE-CT) and thus to clarify whether modern functional imaging can mitigate the need for palpation of bowel during surgery enabling oncologically adequate laparoscopic resection.

Methods

A total of 28 patients with SI-NET who preoperatively underwent both ⁶⁸Ga-DOTATOC/TATE-PET/CT and CE-CT were included. The detection rates of PT and PC for PET/CT and CE-CT were compared to the findings in the surgical and histopathological reports. Appropriate statistical tests were used, and significance was set to p < 0.05.

Results

Out of 82 PT, 43 PT were not detected by any imaging modality. More PT lesions were detected with PET/CT (n = 39 [47.5%]) than with CE-CT (n = 10 [12.2%], p < 0.001). Also, PET/CT identified significantly more PC lesions than CE-CT (78 and 38%, p = 0.004, respectively).

Conclusion

PET/CT detected more PT and PC lesions than CE-CT. Some PTs and PC lesions were only detected by one of the modalities, and CT performed in conjunction with PET/CT should therefore be performed as a fully diagnostic CE-CT for optimal results. Palpation of the small bowel remains crucial during surgery in these patients because several PTs escaped detection by both PET/CT and CE-CT.

Large Cell Neuroendocrine Carcinoma of the Colon With Carcinomatosis Peritonei

Colorectal large-cell neuroendocrine carcinomas (NECs) are extremely rare and have very poor prognosis compared to adenocarcinomas. A 74-year-old man presented with abdominal pain, diarrhea and hematochezia. The histopathologic report of colonoscopic biopsy performed at a local clinic was a poorly differentiated carcinoma. An abdominopelvic computed scan revealed irregularly enhanced wall thickening at the sigmoid colon with regional fat stranding and lymphnode enlargement. He underwent a laparoscopic high anterior resection with selective peritonectomy for peritoneal carcinomatosis, intraoperative peritoneal irrigation chemotherapy, and early postoperative intraperitoneal chemotherapy for 5 days. The tumor had a high proliferation rate (mitotic count > 50/10 HPFs and 90% of the Ki-67 index) and lymph-node metastases had occurred. On immunohistochemistry, the tumor cells expressed CD56 and synaptophysin. Large-cell NEC was confirmed. Systemic chemotherapy with cisplatin/etoposide was done. The patient is still alive after 3 years with no evidence of recurrence.

A 0.8-cm clear cell neuroendocrine tumor G1 of the gallbladder with lymph node metastasis: a case report

BACKGROUND

Neuroendocrine tumors (NETs) of the gallbladder are rare and generally considered low-grade malignancies. We herein describe a case of a patient with a 0.8-cm clear cell NET G1 of the gallbladder with nodal involvement.

CASE PRESENTATION

A 65-year-old man with no medical history indicative of von Hippel-Lindau (VHL) disease underwent laparoscopic cholecystectomy for cholecystolithiasis. There was a 0.8-cm tumor in the neck of the gallbladder. Histologic examination revealed nests or trabecular growth of clear cells with small round-to-oval nuclei. Immunohistochemically, tumor cells showed positivity for chromogranin A and synaptophysin; Ki-67 index was < 1.0%. Based on the World Health Organization 2010 classification, we made a diagnosis of clear cell variant of NET G1 without VHL disease. The tumor invaded the muscular layer and had no extension to the perimuscular connective tissue but had metastasized to a cystic duct node. A radical second resection with regional lymphadenectomy of the gallbladder was performed, and there was no metastasis on histology. After the definitive surgery, he was followed up for 10 months without adjuvant therapy and is alive and well with no evidence of recurrence.

CONCLUSIONS

Our experience suggests that, even when smaller than 1 cm, NET G1 of the gallbladder can metastasize. When NET G1 is incidentally identified in the gallbladder of a surgical specimen, detailed pathologic examination of the cystic duct node, when found, should be performed to guide whether a radical second resection with regional lymphadenectomy is appropriate.

Multilayered heterogeneity as an intrinsic hallmark of neuroendocrine tumors

Neuroendocrine tumors (NETs) comprise a complex and highly heterogeneous group of neoplasms that can arise all over the body, originating from neuroendocrine cells. NETs are characterized by a general lack of symptoms until they are in advanced phase, and early biomarkers are not as available and useful as required. Heterogeneity is an intrinsic, pivotal feature of NETs that derives from diverse causes and ultimately shapes tumor fate. The different layers that conform NET heterogeneity include a wide range of distinct characteristics, from the mere location of the tumor to its clinical and functional features, and from its cellular properties, to the core signaling and (epi)genetic components defining the molecular signature of the tumor. The importance of this heterogeneity resides in that it translates into a high variability among tumors and, hence, patients, which hinders a more precise diagnosis and prognosis and more efficacious treatment of these diseases. In this review, we highlight the significance of this heterogeneity as an intrinsic hallmark of NETs, its repercussion on clinical approaches and tumor management, and some of the possible factors associated to such heterogeneity, including epigenetic and genetic elements, post-transcriptional regulation, or splicing alterations. Notwithstanding, heterogeneity can also represent a valuable and actionable feature, towards improving medical approaches based on personalized medicine. We conclude that NETs can no longer be viewed as a single disease entity and that their diagnosis, prognosis and treatment must reflect and incorporate this heterogeneity.

Gastroenteropancreatic neuroendocrine neoplasms: genes, therapies and models

Gastroenteropancreatic neuroendocrine neoplasms (GEP-NENs) refer to a group of heterogeneous cancers of neuroendocrine cell phenotype that mainly fall into one of two subtypes: gastroenteropancreatic neuroendocrine tumors (GEP-NETs; well differentiated) or gastroenteropancreatic neuroendocrine carcinomas (GEP-NECs; poorly differentiated). Although originally defined as orphan cancers, their steadily increasing incidence highlights the need to better understand their etiology. Accumulating epidemiological and clinical data have shed light on the pathological characteristics of these diseases. However, the relatively low number of patients has hampered conducting large-scale clinical trials and hence the development of novel treatment strategies. To overcome this limitation, tractable disease models that faithfully reflect clinical features of these diseases are needed. In this Review, we summarize the current understanding of the genetics and biology of these diseases based on conventional disease models, such as genetically engineered mouse models (GEMMs) and cell lines, and discuss the phenotypic differences between the models and affected humans. We also highlight the emerging disease models derived from human clinical samples, including patient-derived xenograft models and organoids, which may provide biological and therapeutic insights into GEP-NENs.

Cyto-histology in NET: what is necessary today and what is the future?

The carcinoid as originally described is part of the relatively large family of neuroendocrine neoplasia found in almost every organ. Historical reasons back their current definitions. Neuroendocrine cancer is most frequently observed in the lung and the digestive tract. In the lung is defined as carcinoid (typical and atypical) for well differentiated, low to intermediate grade, and small cell and large cell neuroendocrine carcinoma for poorly differentiated, high grade. In the digestive system are respectively defined as neuroendocrine tumor (NET) and neuroendocrine carcinoma (NEC) of small and large cell types. Grading and staging are developed for their clinical classification by the World Health Organization (WHO) and the American Joint Committee on Cancer (AJCC). In both anatomical sites the morphological features are overlapping, with bland histology for carcinoid and NET, and aggressive features with extensive necrosis, severe atypia and abundant, atypical mitoses for high grade cancer types. Such features are also essential diagnostic clues in cytological preparations. The confirmation of the neuroendocrine signature by immunohistochemistry is mandatory for the diagnosis; a minimum panel comprising chromogranin A and synaptophysin is recommended in the digestive system. In addition, the application of grading requires the mitotic count and or spotty necrosis assessment for lung, or the mitotic count and the Ki67 assessment in the digestive system.