Pancreatic neuroendocrine tumors: biology, diagnosis,and treatment

Comparison of clinical outcomes between enucleation and regular pancreatectomy in patients with non-functional pancreatic neuroendocrine tumors: a retrospective multicenter and propensity score-matched study

OBJECTIVE

There are limited data from retrospective studies on whether therapeutic outcomes after regular pancreatectomy are superior to those after enucleation in patients with small, peripheral and well-differentiated non-functional pancreatic neuroendocrine tumors. This study aimed to compare the short- and long-term outcomes of regular pancreatectomy and enucleation in patients with non-functional pancreatic neuroendocrine tumors.

METHODS

Between January 2007 and July 2020, 227 patients with non-functional pancreatic neuroendocrine tumors who underwent either enucleation (n = 89) or regular pancreatectomy (n = 138) were included. Perioperative complications, disease-free survival, and overall survival probabilities were compared. Propensity score matching was performed to balance the baseline differences between the two groups.

RESULTS

The median follow-up period was 60.76 months in the enucleation group and 43.29 months in the regular pancreatectomy group. In total, 34 paired patients were identified after propensity score matching. The average operative duration in the enucleation group was significantly shorter than that in the regular pancreatectomy group (147.94 ± 42.39 min versus 217.94 ± 74.60 min, P < 0.001), and the estimated blood loss was also significantly lesser (P < 0.001). The matched patients who underwent enucleation displayed a similar overall incidence of postoperative complications (P = 0.765), and a comparable length of hospital stay (11.12 ± 3.90 days versus 9.94 ± 2.62 days, P = 0.084) compared with those who underwent regular pancreatectomy. There were no statistically significant differences between the two groups in disease-free survival and overall survival after propensity score matching.

CONCLUSION

Enucleation in patients with non-functional pancreatic neuroendocrine tumors was associated with shorter operative time, lesser intraoperative bleeding, similar overall morbidity of postoperative complications, and comparable 5-year disease-free survival and overall survival when compared with regular pancreatectomy.

Pancreatic Neuroendocrine Tumor presenting as a diffuse pancreatic enlargement, case report and review of literature

Pancreatic neuroendocrine tumors are rare neoplasms that comprise 1-2% of all pancreatic tumors. However, they are the second most common solid pancreatic neoplasms. They have a wide range of imaging appearances and they can show common to very rare imaging presentations. Most of the time they are solitary well-marginated enhancing solid mass arising in a certain aspect of the pancreas. We present a case report of a 41-year-old female who underwent clinical work-up for abdominal pain, loss of appetite and weight loss for the past year. Ultrasound, computed tomography, and magnetic resonance imaging show diffuse homogenous pancreatic enlargement without contour deformity or a focal mass. Lymphoma and autoimmune pancreatitis were suggested based on imaging findings but IGg4 level and other lab data were normal. Endoscopic ultrasonography confirmed the diffuse enlargement of the pancreas without peripheral structures involvement. The pathological results of multiple fine-needle aspiration biopsy from all parts of the enlarged pancreas revealed a low-grade neuroendocrine tumor.

Imaging neuroendocrine tumors: Characterizing the spectrum of radiographic findings

Neuroendocrine tumors (NET) are a group of neoplasms with neuroendocrine differentiation affecting a wide range of organs. Functional NETs present with symptoms due to the particular hormone produced. Functional NETs are usually small at diagnosis and therefore can be challenging to diagnose. In contrast, non-functioning NETs are generally larger and present with mass effect. Imaging plays an indispensable role in diagnosis, staging and management of patients with NETs. The optimal modality and technique for imaging of NETs depend on the location of primary and metastatic lesions. Regardless of the imaging modality, dynamic contrast-enhanced imaging is essential for evaluation of NETs. In general, CT scan is typically the primary imaging modality for evaluating NETs. MRI is used as a complementary modality, being superior to other modalities to assess liver metastasis. Nuclear medicine imaging is also widely used in NET assessment.

Recurrence of a neuroendocrine tumor of adrenal origin: a case report with more than a decade follow-up

BACKGROUND

Neuroendocrine tumor (NET) with adrenocorticotropic hormone (ACTH) secretion are very rare. To our knowledge, no follow-up study is published for ACTH-secreting NET, regardless of the primary site, to show second occurrence of tumor after a long follow-up, following resection of primary tumor.

CASE PRESENTATION

Here, we describe a 49-year-old-man with cushingoid feature, drowsiness and quadriparesis came to emergency department at December 2005. Laboratory tests revealed hyperglycemia, metabolic alkalosis, severe hypokalemia, and chemical evidence of an ACTH-dependent hypercortisolism as morning serum cortisol of 57 μg /dL without suppression after 8 mg dexamethasone suppression test, serum ACTH level of 256 pg/mL, and urine free cortisol of > 1000 μg /24 h. Imaging showed only bilateral adrenal hyperplasia, without evidence of pituitary adenoma or ectopic ACTH producing tumors. Importantly, other diagnostic tests for differentiating Cushing disease (CD) from ectopic ACTH producing tumor, such as inferior petrosal sinus sampling (IPSS), corticotropin releasing hormone (CRH) stimulation test, octreotide scan or fluorodeoxyglucose (FDG)-positron emission tomography (PET) scan were not available in our country at that time. Therefore, bilateral adrenalectomy was performed that led to clinical and biochemical remission of hypercortisolism and decreased ACTH level to < 50 pg/mL, findings suggestive of a primary focus of NET in adrenal glands. After 11 years uncomplicated follow up, the ACTH level elevated up to 341 pg/mL and re-evaluation showed a 2 cm nodule in the middle lobe of the right lung. Surgical excision of the pulmonary nodule yielded a carcinoid tumor with positive immunostaining for ACTH; leading to decrease in serum ACTH level to 98 pg/mL. Subsequently after 7 months, serum ACHT levels rose again. More investigation showed multiple lung nodules with metastatic bone lesions accompanied by high serum chromogranin level (2062 ng/mL), and the patient managed as a metastatic NET, with bisphosphonate and somatostatin receptor analogues.

CONCLUSION

This case of surgically-treated NET showing a secondary focus of carcinoid tumor after one decade of disease-free follow-up emphasizes on the importance of long-term follow-up of ACTH-secreting adrenal NET.

Application of low dose pancreas perfusion CT combined with enhancement scanning in diagnosis of pancreatic neuroendocrine tumors

PURPOSE

To explore the diagnostic value of pancreatic perfusion CT combined with contrast-enhanced CT in one-time scanning (PCECT) in pancreatic neuroendocrine tumors (PNETs) and to evaluate the difference of perfusion parameters between different grades of PNETs.

MATERIALS AND METHODS

From October 2016 to December 2018, forty consecutive patients with histopathological-proven PNETs were identified retrospectively that received PCECT for the preoperative PNETs evaluation. Two board certified radiologists who were blinded to the clinical data evaluated the images independently. The image characters of PNETs vs. tumor-free pancreatic parenchymal and different grades of PNETs were analyzed.

RESULTS

One-time PCECT scanning had a detection rate of 89.1% for PNETs, which was higher than the detection accuracy of the perfusion CT only (83.6%). The perfusion parameters of PNETs including blood volume (BV), blood flow (BF), mean slope of increase (MSI), and capillary surface permeability (PS) were significantly increased than those of tumor-free pancreatic parenchyma (p < 0.05, respectively). For differential comparison between grade I (G1) and grade II (G2) tumors, the parameters of BF and impulse residue function (IRF) of tumor tissue were significantly higher in the G2 tumors (p < 0.05, for both). In this study, the total radiation dose of the whole PCECT scan was 16.241 ± 2.289 mSv.

CONCLUSION

The one-time PCECT scan may improve the detection of PNETs according to morphological features and perfusion parameters with a relative small radiation dose. The perfusion parameters of BF and IRF may be used to help distinguish G1 and G2 tumors in the preoperative evaluation.

The cytologic and immunohistochemical findings of pancreatic mixed acinar-endocrine carcinoma

BACKGROUND

The classification of epithelioid pancreatic neoplasms based on fine-needle aspiration (FNA) is important for proper management, as distinction of pancreatic neuroendocrine neoplasms from other similar appearing lesions can result in significantly different treatment. Mixed acinar-endocrine carcinomas (MAEC) are genetically related to acinar carcinomas and are treated as such. We reviewed cases of MAEC to better characterize their cytologic and immunohistochemical features.

METHODS

Eight FNAs of MAECs were identified and reviewed. A chart review for each case was conducted.

RESULTS

All patients were male, 42-68 years of age, and presented with either Stage 3 or 4 disease. Smear backgrounds of all cases showed naked nuclei without significant necrosis. The smears were cellular with cells arranged in either three-dimensional (3D) clusters with intervening capillaries or singly dispersed. Acinar formation was a prominent feature. Cells were round to oval with small to moderate amounts of delicate cytoplasm. The nuclei were round to oval with mild to moderate anisonucleosis with granular chromatin and small nucleoli. Apoptotic bodies and mitoses were noted in most cases, with Ki67 indices of 10%-48%. All tumors, by definition, demonstrated expression of trypsin and synaptophysin with variable chromogranin expression (50%).

CONCLUSION

The cytology of acinar cell carcinoma shares features with aspirates of other nonductal adenocarcinoma neoplasms of the pancreas. A clue to the diagnosis is that tumors show high Ki67 indices and a diagnosis of MAEC should be excluded anytime a diagnosis of Grade 2 or 3 well-differentiated neuroendocrine tumor or high-grade neuroendocrine carcinoma is in the differential.

Circulating miRNA Increases the Diagnostic Accuracy of Chromogranin A in Metastatic Pancreatic Neuroendocrine Tumors

Simple Summary

Despite its varying sensitivity and decreased specificity, chromogranin A (CgA) is the most widely used biomarker for neuroendocrine tumors. The most common factor affecting its diagnostic accuracy is the use of proton pump inhibitors (PPIs). Our aim was to investigate circulating miRNA expression profiles in pancreatic neuroendocrine tumors (pNET) and pheochromocytomas/paragangliomas (PPGL) to find miRNAs which could be used as biomarkers along with CgA in these patients. MiRNA expression profiles were determined with next generation sequencing and validated by quantitative real time PCR in 74 samples obtained from patients and healthy volunteers treated with PPI. We observed a global downregulation of miRNAs in NET compared to controls. A set of miRNAs in combination with CgA resulted in the best discrimination of pNET irrespective of PPI treatment and a combination of miRNAs increased the diagnostic utility of CgA even in pNET patients with low CgA.

Abstract

Chromogranin A (CgA) is the most widely accepted biomarker for neuroendocrine tumors (NET) but its diagnostic accuracy is dependent on tumor type and the use of proton-pump inhibitors (PPI). We investigated the diagnostic value of circulating miRNAs along with CgA in pancreatic neuroendocrine tumors (pNET). 74 serum samples from patients with pNET (n = 25, nonfunctioning), pheochromocytoma/paraganglioma (PPGL, n = 20), healthy individuals with normal CgA (n = 29) including 10 samples from 5 healthy individuals with and without current PPI treatment were collected. MiRNA expression profiles were determined using next-generation sequencing, followed by validation with individual TaqMan assays. A global downregulation of miRNAs was observed in patients with NET compared to controls. MiRNA expression of 33 miRNAs was able to discriminate tumor samples from controls. No miRNA alone could be considered as an applicable biomarker for pNET or PPGL. However, using a logistic model, the combination of a set of miRNAs increased the discriminatory role of CgA irrespective of PPI treatment. In pNET patients with normal CgA level our regression model yielded high (89.4%) diagnostic accuracy (AUC: 0.904, sensitivity: 66.6%, specificity: 96.5%). A set of miRNAs increased the diagnostic utility of CgA in pNET even in patients with low CgA.

Pearls and pitfalls of imaging features of pancreatic cystic lesions: a case-based approach with imaging-pathologic correlation

A variety of neoplastic and non-neoplastic lesions of the pancreas can present with a predominantly cystic architecture. These lesions are increasingly being detected as incidental findings on routine cross-sectional imaging following technological advances in these techniques and their widespread use. The different histopathological behaviors show various common and uncommon imaging findings, and some cases show similar appearance in spite of different histopathology. Each lesion requires specific management because of the differing risk of progression to malignancy, and an accurate imaging diagnosis is crucial. The typical imaging characteristics that differentiate pancreatic cystic lesions have been well described and fully summarized. However, in addition to a small percentage of cases that shows uncommon imaging findings, a substantial percentage of cystic lesions shows overlapping imaging findings that can lead to radiological misdiagnosis. For appropriate diagnosis and optimal treatment strategy, it is important to know the uncommon and overlapping imaging findings of these lesions, in addition to familiarity with the typical aspects. In this article, we reconfirm the well-known characteristic imaging features of pancreatic cystic lesions and present several diagnostically challenging cases, focusing on the uncommon and overlapping imaging findings.

Elevated Serum Amino Acids Induce a Subpopulation of Alpha Cells to Initiate Pancreatic Neuroendocrine Tumor Formation

The cellular origin of sporadic pancreatic neuroendocrine tumors (PNETs) is obscure. Hormone expression suggests that these tumors arise from glucagon-producing alpha cells or insulin-producing β cells, but instability in hormone expression prevents linage determination. We utilize loss of hepatic glucagon receptor (GCGR) signaling to drive alpha cell hyperproliferation and tumor formation to identify a cell of origin and dissect mechanisms that drive progression. Using a combination of genetically engineered Gcgr knockout mice and GCGR-inhibiting antibodies, we show that elevated plasma amino acids drive the appearance of a proliferative population of SLC38A5⁺ embryonic progenitor-like alpha cells in mice. Further, we characterize tumors from patients with rare bi-allelic germline GCGR loss-of-function variants and find prominent tumor-cell-associated expression of the SLC38A5 paralog SLC7A8 as well as markers of active mTOR signaling. Thus, progenitor cells arise from adult alpha cells in response to metabolic signals and, when inductive signals are chronically present, drive tumor initiation.

GCGR inhibition induces an SLC38A5⁺ alpha cell population in aged mice

An SLC38A5⁺ alpha cell subpopulation initiates pancreatic tumors in aged Gcgr^−/− mice

Tumors exhibit low mutational burden and response to mTOR inhibition by rapamycin

Tumors in GCGR loss-of-function models lack immune cell infiltration

Zyflamend induces apoptosis in pancreatic cancer cells via modulation of the JNK pathway

Background

Current pharmacological therapies and treatments targeting pancreatic neuroendocrine tumors (PNETs) have proven ineffective, far too often. Therefore, there is an urgent need for alternative therapeutic approaches. Zyflamend, a combination of anti-inflammatory herbal extracts, that has proven to be effective in various in vitro and in vivo cancer platforms, shows promise. However, its effects on pancreatic cancer, in particular, remain largely unexplored.

Methods

In the current study, we investigated the effects of Zyflamend on the survival of beta-TC-6 pancreatic insulinoma cells (β-TC6) and conducted a detailed analysis of the underlying molecular mechanisms.

Results

Herein, we demonstrate that Zyflamend treatment decreased cell proliferation in a dose-dependent manner, concomitant with increased apoptotic cell death and cell cycle arrest at the G2/M phase. At the molecular level, treatment with Zyflamend led to the induction of ER stress, autophagy, and the activation of c-Jun N-terminal kinase (JNK) pathway. Notably, pharmacological inhibition of JNK abrogated the pro-apoptotic effects of Zyflamend. Furthermore, Zyflamend exacerbated the effects of streptozotocin and adriamycin-induced ER stress, autophagy, and apoptosis.

Conclusion

The current study identifies Zyflamend as a potential novel adjuvant in the treatment of pancreatic cancer via modulation of the JNK pathway.

Pancreatic neuroendocrine tumors: Therapeutic challenges and research limitations

Pancreatic neuroendocrine tumors (PNETs) are known to be the second most common epithelial malignancy of the pancreas. PNETs can be listed among the slowest growing as well as the fastest growing human cancers. The prevalence of PNETs is deceptively low; however, its incidence has significantly increased over the past decades. According to the American Cancer Society’s estimate, about 4032 (> 7% of all pancreatic malignancies) individuals will be diagnosed with PNETs in 2020. PNETs often cause severe morbidity due to excessive secretion of hormones (such as serotonin) and/or overall tumor mass. Patients can live for many years (except for those patients with poorly differentiated G3 neuroendocrine tumors); thus, the prevalence of the tumors that is the number of patients actually dealing with the disease at any given time is fairly high because the survival is much longer than pancreatic ductal adenocarcinoma. Due to significant heterogeneity, the management of PNETs is very complex and remains an unmet clinical challenge. In terms of research studies, modest improvements have been made over the past decades in the identification of potential oncogenic drivers in order to enhance the quality of life and increase survival for this growing population of patients. Unfortunately, the majority of systematic therapies approved for the management of advanced stage PNETs lack objective response or at most result in modest benefits in survival. In this review, we aim to discuss the broad challenges associated with the management and the study of PNETs.

Transcriptomic analysis by RNA sequencing characterises malignant progression of canine insulinoma from normal tissue to metastatic disease

Insulinomas (INS) are the most common human and canine functioning pancreatic neuroendocrine tumours. The long-term prognosis for malignant INS is poor, because micrometastases are frequently missed during surgery. As human and canine malignant INS share clinical and histopathological features, dogs have been proposed as models for INS research. Using RNA-sequencing, we conducted a pilot study to better understand the underlying molecular mechanisms of canine INS. Normal canine pancreas and lymph node control tissues were compared with primary INS and INS-metastatic lymph nodes, revealing more than 3,000 genes differentially expressed in normal pancreas compared to primary INS. Only 164 genes were differentially expressed between primary INS and INS-metastatic lymph nodes. Hierarchical clustering analysis demonstrated similar genetic profiles in normal pancreas and early clinical stage primary INS, whereas late clinical stage primary INS resembled the genetic profile of INS-metastatic lymph nodes. These findings suggest that markers of malignant behaviour could be identified at the primary site of the disease. Finally, using the REACTOME pathways database, we revealed that an active collagen metabolism, extracellular matrix remodelling, beta-cell differentiation and non-beta-cell trans-differentiation might cause disease progression and hyperinsulinism in INS, identifying major pathways worthy of future research in this currently poorly controlled disease.

Differences between Well-Differentiated Neuroendocrine Tumors and Ductal Adenocarcinomas of the Pancreas Assessed by Multi-Omics Profiling

Most pancreatic neuroendocrine tumors (PNETs) are indolent, while pancreatic ductal adenocarcinomas (PDACs) are particularly aggressive. To elucidate the basis for this difference and to establish the biomarkers, by using the deep sequencing, we analyzed somatic variants across coding regions of 409 cancer genes and measured mRNA/miRNA expression in nine PNETs, eight PDACs, and four intestinal neuroendocrine tumors (INETs). There were 153 unique somatic variants considered pathogenic or likely pathogenic, found in 50, 57, and 24 genes in PDACs, PNETs, and INETs, respectively. Ten and 11 genes contained a pathogenic mutation in at least one sample of all tumor types and in PDACs and PNETs, respectively, while 28, 34, and 11 genes were found to be mutated exclusively in PDACs, PNETs, and INETs, respectively. The mRNA and miRNA transcriptomes of PDACs and NETs were distinct: from 54 to 1659 differentially expressed mRNAs and from 117 to 250 differentially expressed miRNAs exhibited high discrimination ability and resulted in models with an area under the receiver operating characteristics curve (AUC-ROC) >0.9 for both miRNA and mRNA. Given the miRNAs high stability, we proposed exploring that class of RNA as new pancreatic tumor biomarkers.

Magnesium transporter protein solute carrier family 41 member 1 suppresses human pancreatic ductal adenocarcinoma through magnesium-dependent Akt/mTOR inhibition and bax-associated mitochondrial apoptosis

The aim of this study was to identify the function of the Mg²⁺ transporter protein solute carrier family 41 member 1 SLC41A1 in pancreatic ductal adenocarcinoma and the underlying mechanisms. A total of 27 solute carrier proteins were differentially expressed in pancreatic ductal adenocarcinoma. Three of these proteins were correlated with clinical outcomes in patients, among which SLC41A1 was downregulated in tumour. Overexpression of SLC41A1 suppressed orthotopic tumour growth in a mouse model and reduced the cell proliferation, colony formation, and invasiveness of KP3 and Panc-1 cells, which may have been associated with the increased population of apoptotic-prone cells. Overexpression of SLC41A1 reduced the mitochondrial membrane potential, induced Bax while suppressed Bcl-2 expression. Suppression of Bax abrogated the tumour-suppressive effects of SLC41A1. Furthermore, overexpression of SLC41A1 promoted Mg²⁺ efflux and suppressed Akt/mTOR activity, which is the upstream regulator of Bax and Bcl-2. An increase in Akt activity and supplementation with Mg²⁺ abolished SLC41A1-induced tumour suppression. The results of this study suggest that SLC41A1 may be a potential target for the treatment of pancreatic ductal adenocarcinoma.

Surgical management of primary pancreatic neuroendocrine tumors

Pancreatic neuroendocrine tumors (PanNETs) are the second most common malignancy of the pancreas, and their incidence is increasing. PanNETs are a diverse group of diseases which range from benign to malignant, can be sporadic or associated with genetic mutations, and be functional or nonfunctional. In as much, the treatment and management of PanNETs can vary from a "Wait and See" approach to orthotopic liver transplantation (OLT). Despite this, surgical resection is still the primary treatment modality to achieve cure. This review focuses on the surgical management of PanNETs.

Metastasis in Pancreatic Ductal Adenocarcinoma: Current Standing and Methodologies

Pancreatic ductal adenocarcinoma is an extremely aggressive disease with a high metastatic potential. Most patients are diagnosed with metastatic disease, at which the five-year survival rate is only 3%. A better understanding of the mechanisms that drive metastasis is imperative for the development of better therapeutic interventions. Here, we take the reader through our current knowledge of the parameters that support metastatic progression in pancreatic ductal adenocarcinoma, and the experimental models that are at our disposal to study this process. We also describe the advantages and limitations of these models to study the different aspects of metastatic dissemination.

Overexpression of somatostatin receptor type 2 in neuroendocrine tumors for improved Ga68-DOTATATE imaging and treatment

BACKGROUND

Neuroendocrine tumors are found throughout the body, including the pancreas. These tumors are phenotypically and genetically heterogeneous and can be difficult to accurately image using current imaging standards. However, positron emission tomography/computed tomography with radiolabeled somatostatin analogs has shown clinical success because many neuroendocrine tumors overexpress somatostatin receptor subtype 2. Unfortunately, patients with poorly differentiated neuroendocrine tumors often have a diminished level of somatostatin receptor subtype 2. We found that histone deacetylase inhibitors can upregulate the functional expression of somatostatin receptor subtype 2.

METHODS

We evaluated the effect of histone deacetylase inhibitors on somatostatin receptor subtype 2 expression at the mRNA and protein level in neuroendocrine tumor cell lines. The effect of histone deacetylase inhibitors on surface somatostatin receptor subtype 2 was also investigated by fluorescence-activated cell sorting analysis. Changes in somatostatin receptor subtype 2 expression in neuroendocrine tumor xenografts after treatment were imaged using Ga68-DOTATATE positron emission tomography/computed tomography.

RESULTS

The functional increase of somatostatin receptor subtype 2 in neuroendocrine tumors after histone deacetylase inhibitor treatment was confirmed through in vitro experiments and small animal Ga68-DOTATATE positron emission tomography/computed tomography imaging. Histone deacetylase inhibitors increased somatostatin receptor subtype 2 transcription and protein expression in neuroendocrine tumor cell lines. Small animal Ga68-DOTATATE positron emission tomography/computed tomography imaging confirmed the enhancement of radiopeptide uptake after histone deacetylase inhibitor administration.

CONCLUSION

This study demonstrates a new method to potentially improve imaging and treatments that target somatostatin receptor subtype 2 in neuroendocrine tumors.

EPB41L5 is Associated With the Metastatic Potential of Low-grade Pancreatic Neuroendocrine Tumors

BACKGROUND/AIM

Low-grade pancreatic neuroendocrine tumors (LG-PNETs) behave unpredictably. The aim of the study was to identify biomarkers that predict PNET metastasis to improve treatment selection.

PATIENTS AND METHODS

Five patients with primary non-metastatic LG-PNETs, six with primary LG-PNETs with synchronous or metachronous metastases (M-PNETs), and six metastatic to liver LG-PNETs (ML-PNETs) from the group of six M-PNET patients were selected. RNA data were normalized using iterative rank-order normalization. Student's t-test identified differentially-expressed genes in LG-PNETs versus M-PNETs. A 2-fold difference in expression was considered to be significant. Results were validated with an independent dataset of LG-PNETs and metastatic LG-PNETs.

RESULTS

Overall, 195 genes had a >2-fold change (in either direction). A total of 29 genes were differentially overexpressed in M-PNETs. Erythrocyte membrane protein band 4.1-like 5 (EPB41L5) had a 2.07-fold change increase in M-PNETs and the smallest p-value. EPB41L5 was not statistically different between M-PNETs and ML-PNETs. EPB41L5 differential expression between primary and metastatic LG-PNETs was confirmed by immunohistochemistry.

CONCLUSION

These results support further investigation into whether EPB41L5 is a biomarker of PNETs with high risk for metastases.

Spleen-preserving distal pancreatectomy and lymphadenectomy for glucagonoma syndrome: A case report

RATIONALE

Glucagonoma is a rare type of functional pancreatic neuroendocrine tumor that is characterized by distinctive clinical manifestations; among these, necrolytic migratory erythema represents the hallmark clinical sign of glucagonoma syndrome and is usually presented as the initial complaint of patients.

PATIENT CONCERNS

A 30-year-old male patient was admitted to our hospital with a complaint of diffuse erythematous ulcerating skin rash for more than 10 months. He also complained of hyperglycemia and a weight loss of 15 kg in those months.

DIAGNOSIS

This patient underwent a contrast-enhanced computed tomography scan which showed a pancreatic body mass measuring approximately 6 cm with low density accompanied by partial calcification in plain scanning images and uneven enhancement in strengthening periods. In addition, laboratory tests indicated elevated fasting blood glucagon (1109 pg/mL, normal range: 50-150 pg/mL) levels. Glucagonoma syndrome was ultimately diagnosed in clinical.

INTERVENTION

Spleen-preserving distal pancreatectomy was conducted and postoperative pathology revealed the presence of glucagonoma.

OUTCOMES

The patient recovered uneventfully with the glucagonoma syndrome disappeared soon after surgery, and the postoperative plasma glucagon decreased to a normal level. Follow-up showed no recurrence for 5 years since the surgery.

LESSONS

The treatment of glucagonoma should be directed according to the stage at which the disease is diagnosed. Surgery is currently the only method available to cure the tumor, although medications are given to patients who present with advanced glucagonoma and who are not candidates for operation. Multidisciplinary therapy and multimodality treatment are advised, although these have been systematically evaluated to a lesser degree.

PROINSULIN-PREDOMINANT PANCREATIC NEUROENDOCRINE TUMOR-INDUCED HYPOGLYCEMIA AFTER ROUX-EN-Y GASTRIC BYPASS SURGERY

Objective

To present a case of recurrent hypoglycemia following Roux-en-Y gastric bypass (RYGB) surgery whose etiology was determined to be a proinsulin-predominant pancreatic neuroendocrine tumor (a proinsulinoma).

Methods

A case report along with a brief discussion and review of the pertinent literature is presented.

Results

The patient is a 62-year-old female who presented with symptomatic hypoglycemia 11 years after RYGB surgery. Initial workup revealed low insulin levels with elevated proinsulin levels. A 72-hour fast confirmed the presence of proinsulin-induced hypoglycemia secondary to a pancreatic neuroendocrine tumor (PNET). She underwent distal pancreatectomy with splenectomy and a PNET tumor was successfully removed with resolution of her symptoms.

Conclusion

Hypoglycemia after RYGB surgery is a well-established syndrome. While there are several etiologies for this, PNETs (including proinsulinomas) should be considered in the differential diagnosis in this population. Proinsulinomas are an increasingly recognized cause of hypoglycemia. Proinsulin levels must always be included as part of the workup of hypoglycemia in an adult.

Interesting pancreatic tumour in the background of Tuberous Sclerosis

Tuberous Sclerosis Complex (TSC) is easily discernible by a myriad of manifestations, most notably dermatological. It is associated with well known and recognised intra-abdominal tumours like angiomyolipoma of the kidney. However, rarer tumours like pancreatic neuroendocrine tumours can occur in the setting of TSC. A high index of suspicion is necessary to identify and treat these lesions early in their natural course. Early identification augurs well with complete surgical excision and excellent survival.

lncRNA H19 binds VGF and promotes pNEN progression via PI3K/AKT/CREB signaling

Pancreatic neuroendocrine neoplasms (pNENs) are endocrine tumors arising in pancreas and is the most common neuroendocrine tumors. Mounting evidence indicates lncRNA H19 could be a determinant of tumor progression. However, the expression and mechanism of H19 and the relevant genes mediated by H19 in pNENs remain undefined. Microarray analysis was conducted to identify the differentially expressed lncRNAs in pNENs. H19 expression was analyzed in 39 paired pNEN tissues by qPCR. The biological role of H19 was determined by functional experiments. RNA pulldown, mass spectroscopy and RNA immunoprecipitation were performed to confirm the interaction between H19 and VGF. RNA-seq assays were performed after knockdown H19 or VGF. H19 was significantly upregulated in pNEN tissues with malignant behaviors, and the upregulation predicted poor prognosis in pNENs. In vitro and in vivo data showed that H19 overexpression promoted tumor growth and metastasis, whereas H19 knockdown led to the opposite phenotypes. H19 interacted with VGF, which was significantly upregulated in pNENs, and higher VGF expression was markedly related to poor differentiation and advanced stage. Furthermore, VGF was downregulated when H19 was knocked down, and VGF promoted cell proliferation, migration and invasion. Mechanistic investigations revealed that H19 activated PI3K/AKT/CREB signaling and promoted pNEN progression by interacting with VGF. These findings indicate that H19 is a promising prognostic factor in pNENs with malignant behaviors and functions as an oncogene via the VGF-mediated PI3K/AKT/CREB pathway. In addition, our study implies that VGF may also serve as a candidate prognostic biomarker and therapeutic target in pNENs.

Association between genetic polymorphisms in long non-coding RNAs and pancreatic cancer risk

BACKGROUND

Long non-coding RNAs (lncRNAs) are emerging as candidate biomarkers of cancer, having regulatory functions in both oncogenic and tumor-suppressive pathways. Concerning pancreatic cancer (PC), deregulation of lncRNAs involved in tumor initiation, invasion, and metastasis seem to play a key role. However, data is scarce about regulatory mechanism of lncRNA expression.

OBJECTIVE

The aim of our study was to investigate the contribution of two lncRNAs polymorphisms (rs1561927 and rs4759313 of PVT1 and HOTAIR, respectively) in PC susceptibility.

METHODS

A case-control study was conducted analysing rs1561927 and rs4759313 polymorphisms using DNA collected in a population-based case-control study of pancreatic cancer (111 pancreatic ductal adenocarcinoma cases (PDAC), 56 pancreatic neuroendocrine tumor (PNET), and 125 healthy controls).

RESULTS

Regarding the PVT1 rs1561927 polymorphism the G allele was significantly overrepresented in both PDAC and PNET patients compared to the controls, while the presence of the HOTAIR rs4759314 G allele was found to be overrepresented in the PNET patients only compared to the controls. The PVT1 rs1561927 AG/GG genotypes were associated with poor overall survival in PDAC patients.

CONCLUSIONS

Our results suggested that polymorphisms of these two lncRNA polymorphisms implicated in pancreatic carcinogenesis. Further large-scale and functional studies are needed to confirm our results.

Prevalence of Diagnostic Methods and Treatment Modalities in Vipoma Patients: A Rare Cause of Hormone-Mediated Diarrhea

INTRODUCTION

VIPoma is a neuroendocrine tumor that secrets vasoactive intestinal peptide and produces a well-defined clinical syndrome characterized by watery diarrhea, hypokalemia, hypochlorhydria and metabolic acidosis. The aim of this study to investigate clinical studies about diagnostic and therapeutic modalities of vipoma patients. In this retrospective study, all patients of vipoma were investigated. Clinical features, laboratory data at initial presentation, management and outcomes were collected.

SUBJECTS AND METHODS

The paper has written based on searching PubMed and Google Scholar to identify potentially relevant articles or abstracts. Categorical variables as percentage and continuous variables were reported as mean ± standard deviation (SD).

RESULTS

All the patients presented with watery diarrhea (30/30, 100%) and dehydration was reported in 33.3% of them. Prevalence of laboratory findings in these patients were assessed for hypokalaemia (25/30, 83.3%), metabolic acidosis (9/30, 33.6%), hypochloremia and achlorhydria (2/30, 6.6%). Elevated VIP levels have been seen in 73.3% patients with mean values of 882.85 ± 1134.87 pg/ml. Prevalence of diagnostic methods included CT scan in 19 patients (19/30, 63.3%), ultrasonography (15/50, 50%), and somatostatin receptor scintigraphy (8/30, 26.6%). Medical treatments included somatostatin and analogues in 18 patients (18/30, 60%). Surgery included less percentage of treatment in these patients.

CONCLUSION

CT scan can be used as a reliable modality for diagnosis of vipoma and somatostatin analogues can be used as the most effective treatment in vipoma patients. Surveillance of these patients needs to close monitoring of patients via history, physical examination, laboratory and imaging.

Risk of Primary Neuroendocrine Pancreatic Tumor After a First Primary Cancer: A US Population-Based Study

OBJECTIVE

This study aimed to describe the relative and excess risk of pancreatic neuroendocrine tumor (NET) at least 6 months after the first primary cancer (FPC) among the US population.

METHODS

Surveillance, Epidemiology, and End-Results Program data were analyzed for patients diagnosed as having FPC from 2000 to 2015 (n = 4,008,092). Standardized incidence ratios, excess risk, and average time to diagnosis of a second primary pancreatic NET were reported by FPC site, stratified by sex and receipt of radiotherapy and chemotherapy.

RESULTS

Risk of pancreatic NET was significantly higher after FPC at any site, any solid tumor (standardized incidence ratios, 1.3; 95% confidence interval, 1.2-1.5), pancreas, thymus, small intestine, liver, stomach, kidney, lung, and female breast. Excess incidence of pancreatic NET was highest among those with FPC (especially NET) of the pancreas, bladder, thymus, and female breast; those who received radiotherapy/chemotherapy for bladder, melanoma, and stomach cancers; and those who received chemotherapy for uterine, cervical, prostate, and other genital cancers. Time to diagnosis was shortest after pancreatic, liver, lung, and stomach cancer.

CONCLUSIONS

Cancer survivors have increased risk and excess incidence of primary pancreatic NET compared with the population, particularly for certain primary sites. High-risk patients should receive regular follow-up screenings, counseling to reduce carcinogen exposure, and lifestyle interventions.

Endoscopic Ultrasound Assessment of Pancreatic Duct Diameter Predicts Neuroendocrine Tumors and Other Pancreas Masses

OBJECTIVES

Distinguishing neuroendocrine tumors (NETs) and other pancreas lesions from adenocarcinomas via endoscopic ultrasound (EUS) requires additional tissue for special staining and processing. Our aim was to determine if main pancreatic duct (PD) diameter on EUS helps to differentiate NET and other unusual tumors from adenocarcinoma.

METHODS

We evaluated 30 consecutive patients diagnosed with NET or other pancreas lesions by EUS with 90 matched patients who were found to have adenocarcinoma. Dilated PD was defined as greater than 3 mm. Multivariate logistic regression was used to evaluate associations between lesion type and PD diameter.

RESULTS

Among the 30 patients with NET/other pancreas lesions, 21 had NETs, 7 had metastases, and 2 had lymphomas. A dilated PD was demonstrated in only 3.3% of pancreatic NET/other lesions but present in 88.9% of cases of primary adenocarcinoma (P < 0.01). In multivariate analysis, a normal PD diameter and absence of clinical symptoms strongly predicted the presence of pancreatic NET/other versus adenocarcinoma (P < 0.01).

CONCLUSIONS

The absence of PD dilation upstream of the lesion suggests NET or other lesions rather than adenocarcinoma. This finding should prompt endosonographers to obtain additional tissue at the time of EUS to send for special studies.

Autotaxin upregulated by STAT3 activation contributes to invasion in pancreatic neuroendocrine neoplasms

Although the upregulation of autotaxin (ATX) is associated with many solid tumours, its role in pancreatic neuroendocrine neoplasms (pNEN) has not been well elucidated. The expression of ATX in pNEN tissues and pNEN cell line BON1 was analysed by Western blot, PCR and immunocytochemistry upon exposure to interleukin-6 (IL-6). Additionally, pNEN cell line BON1 was transfected with siRNAs against ATX or signal transducer and activator of transcription 3 (STAT3) and assessed by in vitro invasion assays. The following results were obtained. The expression of ATX in pNEN tissues was significantly increased compared with that in normal pancreatic tissues. High ATX expression was strongly correlated with tumour grade, lymph node metastasis and tumour-node-metastasis stage. Furthermore, ATX downregulation notably inhibited the metastatic capacity of pNEN cells, whereas STAT3 knockdown was found to downregulate the expression of ATX. ATX expression was upregulated in BON1 cells upon stimulation with IL-6, and this was accompanied by activation/phosphorylation of STAT3. Western blot analysis of human pNEN tissue extracts confirmed increased ATX expression and STAT3 phosphorylation with elevated expression levels of IL-6. In conclusion, ATX is upregulated in pNEN and is correlated with the metastatic capacity of pNEN cells, potentially via interaction with STAT3 activation.

Effect of Endostar combined with chemotherapy in advanced well-differentiated pancreatic neuroendocrine tumors

The aim of the present study was to assess the effect of Endostar and temozolomide or dacarbazine plus 5-fluorouracil (5-FU) in patients with advanced pancreatic neuroendocrine tumors (pNETs).Phase II study of 14 patients with locally advanced or metastatic well-differentiated pNETs treated between April 2013 and September 2016. Patients received temozolomide or dacarbazine plus 5-FU, and Endostar. The primary outcome was the radiographic response rate.All 14 patients had nonfunctional pNETs. Six patients received temozolomide and 8 received dacarbazine + 5-FU, combined with Endostar. Thirteen patients were assessable for treatment response: 1(7%) with complete response, 5 (39%) with partial response, 5 (39%) with stable disease, and 2 (15%) with progression. The median progression-free survival was 12 months. The most common grade 1/2 toxicities were neutropenia (43%) and leucopenia (21%).Endostar combined with temozolomide or dacarbazine + 5-FU was effective in the treatment of advanced pNETs. The combinations were well tolerated.

Reduced expression of the RNA-binding protein HuD in pancreatic neuroendocrine tumors correlates with low p27Kip1 levels and poor prognosis

For the majority of patients diagnosed with pancreatic neuroendocrine tumors (NETs), there is significant malignant potential with a poor prognosis; however, the molecular abnormalities and pathogenesis of pancreatic NETs have not been firmly established. Here, we report that loss of expression of the RNA-binding protein HuD correlates with low p27^Kip1 (p27) levels and poor prognosis in pancreatic NETs. HuD expression was frequently lost in many human pancreatic NETs, and these pancreatic NETs showed aggressive clinicopathological phenotypes with low p27 levels, increased tumor size, higher World Health Organization grade and pT stage of the tumor, and the presence of angioinvasion. Furthermore, loss of HuD was an independent, progression-free prognostic factor in multivariate survival analysis. However, the level of HuR, a member of the same Hu protein family as HuD, was not significantly correlated with pancreatic NET size and progression. Mechanistically, HuD enhanced p27 mRNA translation by interacting with both the 5'-untranslated region (UTR) and the 3'-UTR of p27 mRNA, and consequently suppressed cell cycle progression and tumor growth. In addition, HuD competed with miR-30a-3p for binding to the 3'-UTR of p27 mRNA, suggesting an interplay between HuD and miR-30a-3p in controlling p27 translation. Our results identify HuD as a pivotal suppressor of pancreatic NET growth, and suggest that HuD has potential value as a prognostic factor of pancreatic NETs. Copyright © 2018 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Interpretation of Unexpectedly High Levels of Endocrine Tumor Markers

OBJECTIVE

Endocrine tumor markers (ETMs) are important and indispensable tools in the diagnosis and follow-up of endocrine tumors. Unexpectedly high level of ETM (UHLETM) is often encountered in clinical practice. The objectives of this article are to discuss the approach to UHLETMs and describe the most common UHLETMs.

METHODS

Literature review and personal experience with UHLETMs.

RESULTS

A UHLETM is defined as an ETM level much higher than what an endocrinologist would expect based on the patient's clinical information, other biochemical test results, and imaging findings. Most UHLETMs are false positive, in that they do not indicate the existence or growth of an endocrine tumor. The key issue, however, is how to convincingly prove that a UHLETM is false positive. The most important question to help resolve UHLETMs is whether the UHLETMs are due to false or true results. Some UHLETMs are due to interpretation errors, laboratory errors, or spurious test results, while the true levels of the ETMs are normal or unchanged from previous results. Other UHLETMs are due to nontumor conditions or medications, and the true levels of the ETMs are indeed very high. When it is not straightforward to assess whether certain UHLETMs are due to false or true results, they may be due to novel conditions.

CONCLUSION

UHLETMs provide endocrinologists great opportunities to learn the basic biology and measurement of ETMs. Unresolved UHLETMs are exciting clinical research opportunities which may lead to discovery of new diseases and new mechanisms of measurement interference.

ABBREVIATIONS

5-HIAAA = 5-hydroxyindoleacetic acid; 5-HTP = 5-hydroxytryptophan; CGA = chromogranin A; ETM = endocrine tumor marker; MTC = medullary thyroid carcinoma; UHLETM = unexpectedly high level of endocrine tumor marker.

Treatment options for PNET liver metastases: a systematic review

BACKGROUND

Pancreatic neuroendocrine tumors (PNETs) are rare pancreatic neoplasms. About 40-80% of patients with PNET are metastatic at presentation, usually involving the liver (40-93%). Liver metastasis represents the most significant prognostic factor. The aim of this study is to present an up-to-date review of treatment options for patients with liver metastases from PNETs.

METHODS

A systematic literature search was performed using the PubMed database to identify all pertinent studies published up to May 2018.

RESULTS

The literature search evaluated all the therapeutic options for patients with liver metastases of PNETs, including surgical treatment, loco-regional therapies, and pharmacological treatment. All the different treatment options showed particular indications in different presentations of liver metastases of PNET. Surgery remains the only potentially curative therapeutic option in patients with PNETs and resectable liver metastases, even if relapse rates are high. Efficacy of medical treatment has increased with advances in targeted therapies, such as everolimus and sunitinib, and the introduction of radiolabeled somatostatin analogs. Several techniques for loco-regional control of metastases are available, including chemo- or radioembolization.

CONCLUSIONS

Treatment of patients with PNET metastases should be multidisciplinary and must be personalized according to the features of individual patients and tumors.

Neuropilin-1 (NRP-1) upregulated by IL-6/STAT3 signaling contributes to invasion in pancreatic neuroendocrine neoplasms

Although the upregulation of Neuropilin-1 (NRP-1) is associated with many solid tumors, its role in pancreatic neuroendocrine neoplasms (pNEN) has not been well elucidated. The aim of this study was to investigate the role of NRP-1 in improving treatment and determining the prognosis of pNEN. In this study, the expression of NRP-1 in pNEN tissue samples and pNEN cell line BON1 was analyzed by Western blot, polymerase chain reaction (PCR) and immunocytochemistry upon exposure to interleukin-6 (IL-6). Additionally, pNEN cell line BON1 was transfected with small interfering RNAs against NRP-1 or signal transducer and activator of transcription 3 (STAT3) and assessed by in vitro invasion assays. The expression of NRP-1 in pNEN tissues was markedly increased compared with adjacent normal pancreatic tissues. High NRP-1 expression was strongly correlated with tumor grades (P = .026), lymph node metastasis (P = .025), and tumor-node-metastasis stages (P = .012). Furthermore, NRP-1 downregulation notably inhibited the metastatic capacity of pNEN cells, and STAT3 knockdown was found to downregulate the expression of NRP-1. BON1 cells upregulated NRP-1 expression upon stimulation with IL-6. This was accompanied by activation/phosphorylation of the AKT and STAT3 signaling pathways. Western blot of extracts of human pNENs confirmed increased NRP-1 expression, as well as AKT/STAT3 phosphorylation in tissue of pNENs with elevated expression levels of IL-6. In conclusion, our findings suggest that NRP-1 is upregulated in pNEN and is correlated with the metastatic capacity of pNEN cells, potentially via interaction with the IL-6/STAT3 signaling pathway.

Genetics of Pancreatic Neoplasms and Role of Screening

There is a wide spectrum of pancreatic neoplasms with characteristic genetic abnormalities, tumor pathways, and histopathology that primarily determine tumor biology, treatment response, and prognosis. Although most pancreatic tumors are sporadic, 10% of neoplasms occur in the setting of distinct hereditary syndromes. Detailed studies of these rare syndromes have allowed researchers to identify a myriad of specific genetic signatures of pancreatic tumors. A better understanding of tumor genomics may have significant clinical implications in the diagnosis and management of patients with pancreatic tumors. Evolving knowledge has paved the way to screening paradigms and protocols in individuals at higher risk of developing pancreatic tumors.

Nonhypervascular pancreatic neuroendocrine tumors: Spectrum of MDCT imaging findings and differentiation from pancreatic ductal adenocarcinoma

PURPOSE

The purpose of our study was to determine contrast-enhanced MDCT features to differentiate nonhypervascular pancreatic neuroendocrine tumors (PNETs) from pancreatic ductal adenocarcinomas (PDACs).

METHODS

and materials: We included 74 patients with PNETs and 80 patients with PDACs who underwent preoperative MDCT. Two radiologists evaluated the morphologic characteristic and enhancement patterns of the tumors. Quantitative and qualitative analysis was performed, including evaluation of tumor size, homogeneity, contrast enhancement pattern, presence of pancreatic duct dilatation and tumor invasion to the adjacent vessels and peripancreatic infiltration. Tumor-to-pancreas enhancement ratio was defined as the Hounsfield units (HU) value of the tumor divided by the HU value of the pancreas. the first group was hypervascular PNETs showing hyperenhancement on arterial phase images and nonhypervascular PNETs, showing iso- or hypoenhancement on arterial phase images. After that, two radiologists estimated the possibilities of PNET or PDAC were for nonhypervascular PNETs.

RESULTS

On the basis of arterial enhancement, 43 PNETs were hypervascular and 31 were nonhypervascular. When compared to PDAC, nonhypervascular PNETs more frequently had well-defined tumor margins, intratumoral cystic components, calcifications and blood vessels and less frequently had main pancreatic duct dilatation, peripancreatic infiltration and vascular invasion (p < 0.01 for all). Nonhypervascular PNETs had higher tumor-to-pancreas enhancement ratio in venous phase (1.02 vs. 0.78, p = 0.012). Nonhypervascular PNETs more often had portal-venous hyperenhancement or persistent isoenhancement, while PDAC more often had persistent hypoenhancement or gradual delayed enhancement (p < 0.001). The absence of pancreatic duct dilatation and portal-venous hyperenhancement or persistent isoenhancement were the independent predictors for nonhypervascular PNETs. (The most accurate MDCT-findings to predict nonhypervascular PNET were the absence of pancreatic duct dilatation and peripancreatic infiltration (79% and 92% accuracy), portal-venous phase hyperenhancement or persistent isoenhancement (77%), the presence of intratumoral blood vessels (77%) and relative enhancement intensity in venous phase >0.9 (76%). Using these criteria, the area under curve for differentiation of PNET from PDAC was 0.906-0.846.

CONCLUSION

Combined assessment of the enhancement and morphologic characteristics can improve the differentiation between nonhypervascular PNETs and PDAC at contrast-enhanced MDCT.

Hypervascular pancreatic "lesions": a pattern-based approach to differentiation

Hypervascular pancreatic lesions/masses can arise due to a variety of causes, both benign and malignant, leading to a wide differential diagnosis. Accurate differentiation of these lesions into appropriate diagnoses can be challenging; however, this is important for directing clinical management. This manuscript provides a multimodality imaging review of hypervascular pancreatic lesion, with emphasis on an imaging-based algorithmic approach for differentiation of these lesions, which may serve as a decision support tool when encountering these uncommon lesions. Additionally, we stratify these lesions into three categories based on malignant potential, to help guide clinical management.

Nfe2l1-silenced insulinoma cells acquire aggressiveness and chemoresistance

The transcription factor nuclear factor erythroid 2-like 1 (NFE2L1 or NRF1) is involved in various critical cell processes such as maintenance of ubiquitin-proteasome system and regulation of the cellular antioxidant response. We previously determined that pancreatic β-cell-specific Nfe2l1-knockout mice had hyperinsulinemia and that silencing of Nfe2l1 in mouse islets or MIN6 insulinoma β-cells induced elevated basal insulin release and altered glucose metabolism. Hypoglycemia is a major issue with aggressive insulinomas, although a role of NFE2L1 in this pathology is not defined. In the present work, we studied the tumorigenicity of Nfe2l1-deficient insulinoma MIN6 cells (Nfe2l1-KD) and sensitivity to chemotherapy. Nfe2l1-KD cells grew faster and were more aggressive than Scramble cells in vitro In a mouse allograft transplantation model, insulinomas arising from Nfe2l1-KD cells were more aggressive and chemoresistant. The conclusion was amplified using streptozotocin (STZ) administration in an allograft transplantation model in diabetic Akita background mice. Furthermore, Nfe2l1-KD cells were resistant to damage by the chemotherapeutic drugs STZ and 5-fluorouracil, which was linked to binding of hexokinase 1 with mitochondria, enhanced mitochondrial membrane potential and closed mitochondrial potential transition pore. Overall, both in vitro and in vivo data from Nfe2l1-KD insulinoma cells provided evidence of a previously un-appreciated action of NFE2L1 in suppression of tumorigenesis. Nfe2l1 silencing desensitizes insulinoma cells and derived tumors to chemotherapeutic-induced damage, likely via metabolic reprograming. These data indicate that NFE2L1 could potentially play an important role in the carcinogenic process and impact chemosensitivity, at least within a subset of pancreatic endocrine tumors.

The diagnostic value of FNA biopsy in grading pancreatic neuroendocrine tumors

BACKGROUND

There has been much controversy regarding the accuracy of grading pancreatic neuroendocrine tumors (PNETs) on fine-needle aspiration (FNA) biopsy. The objectives of this study were to evaluate whether grading according to the fraction of Ki-67-positive tumor cells (the Ki-67 proliferation index) on material from endoscopic ultrasound-guided FNA biopsies correlated with grading on surgical resection specimens and to evaluate the minimum amount of FNA material needed.

METHODS

A case series of 27 PNETs with FNA biopsies and corresponding surgical resection specimens at the authors' institution were evaluated. Tumors were graded on FNA and surgical specimens with an evaluation of Ki-67 index according to 2010 World Health Organization criteria. Chart reviews were conducted to evaluate recurrence or clinical progression in patients who were being managed conservatively with observation.

RESULTS

The evaluation of grading between FNA and tumor resection specimens revealed that 22 of 26 FNA specimens (84.6%) had Ki-67 results comparable to those in the corresponding surgical resection specimens, thus allowing for accurate grading. Correct FNA diagnosis with the ability to distinguish between grade 1 and 2 tumors had a positive predictive value of 88.9%, with 72.7% sensitivity, 93.3% specificity, and a P value of .00081. In addition, 24 of 26 cases contained less than 2000 cells, of which 20 were correctly graded on FNA material. Seven of 26 FNA samples had less than 1000 cells, of which 6 were correctly graded, including 2 that had only 50 cells.

CONCLUSIONS

The current results exhibit good correlation between FNA grade and final grade on surgical resection specimens using Ki-67 index, even in samples with less than the recommended total cell count. Therefore, grading of PNETs on FNA with the Ki-67 proliferation index should be assessed and is a practical parameter to report to clinicians. Cancer Cytopathol 2018;126:170-8. © 2017 American Cancer Society.

Preoperative neutrophil-to-lymphocyte ratio and tumor-related factors to predict lymph node metastasis in nonfunctioning pancreatic neuroendocrine tumors

The lymph node (LN) status is very important for the survival in pancreatic neuroendocrine tumors (PNETs). Therefore, the investigation of factors related to LN metastases has a great clinical significance. The aim of this study was to evaluate the predictive value of the preoperative neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR) and possible clinical parameters on the LN metastases in nonfunctional PNETs (NF-PNETs). A retrospective review of 101 NF-PNET patients following curative resection and lymphadenectomy was conducted. The associations between clinicopathological factors and LN metastases and prognosis were determined. Twenty-seven (26.7%) patients had LN metastases. LN metastases was independently associated with disease-free survival (P = 0.009). Ideal cutoff values for predicting LN metastases were 1.80 for NLR, 168.25 for PLR and 2.5 cm for tumor size according to the receiver operating characteristic curve. On multivariable analysis, NLR (P = 0.017), symptomatic diagnosis (P = 0.028) and tumor size (P = 0.020) were associated with LN metastases. These results indicate that preoperative NLR ≥ 1.80, tumor size ≥2.5 cm and symptomatic diagnosis are independently associated with LN metastases for patients undergoing resection of NF-PNETs. It is anticipated that these findings are useful for further planning of lymphadenectomy before surgery.

Imaging of Neuroendocrine Tumors: Indications, Interpretations, Limits, and Pitfalls

Imaging is critical in the diagnosis, prognosis, and management of neuroendocrine tumors (NETs). NETs share common imaging features, but each type exhibits unique features. Computed tomography scans or MRI of the abdomen is used to assess tumor burden routinely. Functional imaging with octreotide scan or gallium-68 somatostatin analog PET is used selectively to confirm diagnosis and guide therapy. Clinicians and radiologists should be familiar with the indications and interpretations of imaging modalities. Novel functional imaging modalities likely will be developed to detect small NETs, predict prognosis, guide therapeutic choices, and design novel therapies.

Clinicopathologic characteristics and prognosis of gastroenteropancreatic neuroendocrine neoplasms: a multicenter study in South China

Background

Gastroenteropancreatic neuroendocrine neoplasms (GEP-NENs) are a heterogeneous group of rare tumors. Many issues in terms of epidemiologic features, pathogenesis, and treatment of GEP-NENs are still under discussion. Our study aimed to analyze the clinicopathologic characteristics and prognosis of Chinese patients with GEP-NENs.

Methods

Complete clinicopathologic data and survival information of 1183 patients with GEP-NENs treated between 2005 and 2015 were collected from five medical centers in Guangdong Province, China. Patient survival was estimated using the Kaplan–Meier method and analyzed using the log-rank test; prognostic factors were analyzed using the Cox proportional hazards model.

Results

The most common tumor location was the rectum (37.4%), followed by the pancreas (28.1%), stomach (20.7%), small intestine (7.2%), appendix (3.4%), and colon (3.3%). After initial definitive diagnosis, 1016 (85.9%) patients underwent surgery. The 1-, 3-, and 5-year overall survival (OS) rates for the entire cohort were 87.9%, 78.5%, and 72.8%, respectively. The 3-year OS rates of patients with G1, G2, and G3 tumors were 93.1%, 82.7%, and 43.1%, respectively (P < 0.001). The 3-year OS rates of patients with stage I, II, III, and IV tumors were 96.0%, 87.3%, 64.0%, and 46.8%, respectively (P < 0.001). Patients with distant metastasis who underwent palliative surgery had a longer survival than those who did not (P = 0.003). Similar survival benefits of palliative surgery were observed in patients with neuroendocrine tumor (P = 0.031) or neuroendocrine carcinoma (P = 0.046). In multivariate analysis, age, grade, N category, M category, and surgery were found to be independent prognostic factors.

Conclusions

Patients with GEP-NENs who are women, younger than 50 years old, have smaller tumor size, have lower tumor grade, have lower T/N/M category, and who undergo surgery can have potentially longer survival time. Our data showed that surgery can improve the prognosis of GEP-NEN patients with distant metastasis. However, randomized controlled trials need to be conducted to establish the optimal criteria for selecting patients to undergo surgery.

Non-functioning pancreatic neuroendocrine tumors: Surgery or observation?

Incidentally detected, sporadic, nonfunctional pancreatic neuroendocrine tumors are increasingly diagnosed on imaging studies performed for unrelated purposes. Although their resection is usually recommended, controversy still exists regarding their optimal management, due to their highly variable and difficult to predict biologic behavior. Recently, several studies and guidelines advocated an expectant management approach in small size, low grade, incidentally diagnosed nonfunctional pancreatic neuroendocrine tumors. The aim of this study is to review and summarize the available literature addressing nonfunctional pancreatic neuroendocrine tumors, with an emphasis on surgical management controversies.

A Clinicopathological Study of Malignant Insulinoma in a Contemporary Series

OBJECTIVE

The aim of the study was to address the origin and natural history of malignant insulinoma.

METHODS

Retrospective review of medical records of patients diagnosed with insulinoma at Cedars-Sinai Medical Center between 2000 and 2015 was conducted. Hormonal expression in tumor specimens was examined by immunostaining.

RESULTS

All the 9 patients with malignant insulinoma (35% of 26 patients with insulinoma) already had liver metastasis at hypoglycemia presentation with bulky cumulative tumor burden. Six patients had de novo diagnosis, 2 had known metastatic nonfunctioning pancreatic neuroendocrine tumor, and 1 had a known pancreatic mass. Tumor grade at presentation was G1 in 4 patients, G2 in 4, and unknown in 1. Four patients died 2 to 32 months after presentation, all with extensive liver tumor involvement. Tumor expression of proinsulin and insulin was heterogeneous and overall infrequent. The proinsulin levels and proinsulin/insulin molar ratio in patients with malignant versus benign insulinoma were 334 versus 44 pmol/L and 2.1 versus 0.9, respectively.

CONCLUSIONS

Malignant insulinoma seems to arise from and behave like nonfunctioning pancreatic neuroendocrine tumor oncologically but with metachronous hyperinsulinemic hypoglycemia. High proinsulin levels and proinsulin/insulin molar ratio may suggest malignant insulinoma.

Pancreatic α-cell hyperplasia and hyperglucagonemia due to a glucagon receptor splice mutation

Glucagon stimulates hepatic glucose production by activating specific glucagon receptors in the liver, which in turn increase hepatic glycogenolysis as well as gluconeogenesis and ureagenesis from amino acids. Conversely, glucagon secretion is regulated by concentrations of glucose and amino acids. Disruption of glucagon signaling in rodents results in grossly elevated circulating glucagon levels but no hypoglycemia. Here, we describe a patient carrying a homozygous G to A substitution in the invariant AG dinucleotide found in a 3′ mRNA splice junction of the glucagon receptor gene. Loss of the splice site acceptor consensus sequence results in the deletion of 70 nucleotides encoded by exon 9, which introduces a frame shift and an early termination signal in the receptor mRNA sequence. The mutated receptor neither bound ¹²⁵I-labeled glucagon nor induced cAMP production upon stimulation with up to 1 µM glucagon. Despite the mutation, the only obvious pathophysiological trait was hyperglucagonemia, hyperaminoacidemia and massive hyperplasia of the pancreatic α-cells assessed by histology. Our case supports the notion of a hepato–pancreatic feedback system, which upon disruption leads to hyperglucagonemia and α-cell hyperplasia, as well as elevated plasma amino acid levels. Together with the glucagon-induced hypoaminoacidemia in glucagonoma patients, our case supports recent suggestions that amino acids may provide the feedback link between the liver and the pancreatic α-cells.

mTOR inhibitors response and mTOR pathway in pancreatic neuroendocrine tumors

Medical therapy of pancreatic neuroendocrine tumors (P-NET) may take advantage of Everolimus treatment. However, the extent of therapeutic response cannot be predicted. This study was aimed to identify the possible predictive markers of response to Everolimus in P-NET. We found that Everolimus reduced the cell viability and induced apoptosis in primary cultures of 6 P-NET (P-NET-R), where the proliferative and antiapoptotic effects of IGF1 were blocked by Everolimus. On the contrary, 14 P-NET primary cultures (P-NET-NR) were resistant to Everolimus and IGF1, suggesting an involvement of PI3K/AKT/mTOR pathway in the mechanism of resistance. The response to Everolimus in vitro was associated with an active AKT/mTOR pathway and seemed to be associated with a greater clinical aggressiveness. In addition, a patient sensitive to Everolimus in vitro was sensitive to this drug in vivo also and showed a positive p-AKT immunohistochemistry (IHC) at tissue level. Similarly, a patient resistant to Everolimus treatment after surgery was not sensitive to the drug in vitro and had a negative p-AKT IHC staining. Therefore, present data confirm that P-NET primary cultures may be considered a model for testing medical treatment efficacy and that IHC characterization of p-AKT might help in identifying human P-NET who can benefit from Everolimus treatment. These data encourage conducting a prospective multicenter study involving different groups of P-NET patients treated with Everolimus.

Management of pancreatic gastrinoma associated with Von Hippel-Lindau disease: a case report

BACKGROUND

Pancreatic neuroendocrine tumors (PNET) are a heterogeneous group and constitute 1.3% of all pancreatic tumors. Approximately 10% of these occur in the context of hereditary syndromes, such as VHL disease.

CASE REPORT

We report a case of a female patient of 37 years diagnosed VHL and intervened on several occasions by cerebral hemangioblastoma and renal carcinomas. During its follow-up she was diagnosed 2 gastrinomas functioning under 2 cm were enucleated. Later developed new PNET and underwent a total duodenopancreatectomy without pyloric preservation.

DISCUSSION

The management of PNET in VHL is difficult due to the association of multiple tumors in different organs and the morbidity and mortality associated with the surgery of the pancreas. Management must be individualized for each patient, based on the ability to produce hormones and present symptoms, the size and location, and in the context of other tumors that usually present in these patients.