Inherited pancreatic endocrine tumor syndromes: advances in molecular pathogenesis, diagnosis, management, and controversies

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

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

Identification of dysregulated pathways associated with pancreatic cancer by survival analysis

In order to identify the dysregulated pathways associated with pancreatic cancer, the fourth leading cause of cancer mortality in the United States, tumor and non-tumor samples were systematically analyzed in the present study. Initially, dysregulated genes in pancreatic cancer were identified using paired t-test. Subsequently, dysregulated biological pathways involved in the development of pancreatic cancer were identified by enrichment analysis. Finally, individual survival analysis of the significantly dysregulated functions was conducted at the pathway level. Our results indicated that the pathway named ̔Pathways in cancer was significantly correlated with survival time. In addition, the mean survival time of individual and genetic variation demonstrated a significantly negative correlation, that is, the lower the genetic variation, the longer the survival time. Furthermore, detailed analysis of genes on the pathway named ̔Pathways in cancer denoted that this pathway involved multiple cancer hallmark signals and several dysregulated cancer genes, including tumor protein p53, myelocytomatosis, Kirsten rat sarcoma, phosphatidylinositol 3-kinase, v-raf murine sarcoma viral oncogene homolog B1 and cyclin-dependent kinase inhibitor 2A. According to the DrugBank database, certain oncogenes have been validated to be the targets of drugs, including Sorafenib, Trastuzumab, Imatinib and Paclitaxel or were under investigation. An improved understanding of the pathophysiology of pancreatic cancer has been achieved based on our results and the present study aimed to provide guidance for the development of drugs to treat pancreatic cancer.

Nordic guidelines 2014 for diagnosis and treatment of gastroenteropancreatic neuroendocrine neoplasms

BACKGROUND

The diagnostic work-up and treatment of patients with neuroendocrine neoplasms (NENs) has undergone major recent advances and new methods are currently introduced into the clinic. An update of the WHO classification has resulted in a new nomenclature dividing NENs into neuroendocrine tumours (NETs) including G1 (Ki67 index ≤ 2%) and G2 (Ki67 index 3-20%) tumours and neuroendocrine carcinomas (NECs) with Ki67 index > 20%, G3. Aim. These Nordic guidelines summarise the Nordic Neuroendocrine Tumour Group's current view on how to diagnose and treat NEN-patients and are meant to be useful in the daily practice for clinicians handling these patients.

GEP-NETS update: a review on surgery of gastro-entero-pancreatic neuroendocrine tumors

The incidence of neuroendocrine tumors (NETs) has increased in the last decades. Surgical treatment encompasses a panel of approaches ranging from conservative procedures to extended surgical resection. Tumor size and localization usually represent the main drivers in the choice of the most appropriate surgical resection. In the presence of small (<2 cm) and asymptomatic nonfunctioning NETs, a conservative treatment is usually recommended. For localized NETs measuring above 2 cm, surgical resection represents the cornerstone in the management of these tumors. As they are relatively biologically indolent, an extended resection is often justified also in the presence of advanced NETs. Surgical options for NET liver metastases range from limited resection up to liver transplantation. Surgical choices for metastatic NETs need to consider the extent of disease, the grade of tumor, and the presence of extra-abdominal disease. Any surgical procedures should always be balanced with the benefit of survival or relieving symptoms and patients' comorbidities.

Pancreatic neuroendocrine tumors: pathologic and molecular characteristics

Pancreatic neuroendocrine neoplasms include mainly well-differentiated neuroendocrine tumors but also rare poorly differentiated neuroendocrine carcinomas. Molecular mechanisms underlying pancreatic neuroendocrine tumorigenesis have recently been elucidated. While alterations in the chromatin remodeling and PI3K/Akt/mTOR pathways are present in most well-differentiated pancreatic neuroendocrine tumors, mutations in TP53 and RB may contribute to the development of pancreatic poorly differentiated neuroendocrine carcinomas. With these discoveries, new molecular targeted therapies have become available and show promise in some patients with pancreatic well-differentiated neuroendocrine tumor.

A Novel Deletion Mutation in the MEN1 Gene in a Patient with Prolactinoma and a Family History of Pancreatic Tumors

OBJECTIVE

Multiple endocrine neoplasia type 1 (MEN1) is an autosomal dominant tumor syndrome caused by mutations in the MEN1 gene. Mutations in this tumor suppressor gene are often associated with neuroendocrine tumors. Here we describe a novel deletion mutation at codon 304 in the MEN1 gene of a patient with a prolactinoma and strong family history of pancreatic tumors.

METHODS

We describe the patient's clinical course and mutational analysis and review the relevant literature.

RESULTS

A 30-year-old pregnant female was referred to our institution's psychological department for treatment of depression. She had developed a prolactinoma at age 17 and was being treated with 1 mg/week of cabergoline. A medical interview revealed a family history of pancreatic islet cell and other tumors; her mother died of pancreatic cancer, her brother is living with gastrinoma, and her sister died of leiomyosarcoma. Extensive examinations performed after delivery, including laboratory tests and computed tomography (CT) scans, did not reveal any other tumors. Mutational analysis of the MEN1 gene identified a heterozygous deletion mutation (c911_914delAGGT) at codon 304. This mutation produces a frameshift at p.304Lys and might disturb the splicing of intron 6 due to the lack of a donor site. The predicted menin protein from the mutated allele is truncated at amino acid 328.

CONCLUSION

We report a novel deletion mutation (c911_914delAGGT) in the MEN1 gene that was likely associated with the patient's prolactinoma and her strong family history of pancreatic tumors.

The value of endoscopic ultrasound in a 47-year-old man with cystic lesions of the liver and pancreas

Most neuroendocrine tumors (NETs), like other tumors, are clinically silent, producing symptoms only as a consequence of tumor growth. Pancreatic NETs account for only 1% of pancreatic cancers by incidence, while representing 10% of all pancreatic cancers by 28-year limited duration prevalence. Here, we present a 47-year-old man with abdominal pain, icterus, itching and 8 kg weight loss during 5 months. Elevated liver enzymes, direct bilirubin and alkaline phosphatase were observed. Magnetic resonance cholangiopancreatography showed a prominence at the head of the pancreas and also liver cysts. Endoscopic ultrasound of the pancreas was performed and a specimen was obtained via fine needle aspiration. Immunohistochemical staining was performed and the result was compatible with NET. The patient referred to receive chemotherapy.

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

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

Gastroenteropancreatic neuroendocrine (carcinoid) tumors in children

Neuroendocrine tumors (NETs) (previously termed carcinoids) are slow-growing tumors of the neuroendocrine system. They can occur anywhere within the body but are most commonly found in the midgut. This review is therefore confined to a discussion of gastroenteropancreatic NETS (GEP-NETS). GEP-NETS may be asymptomatic and are found incidentally (eg, during appendicectomy) or can present with symptoms attributable to either the site of the primary tumor or the secretion of serotonin and other substances from metastatic carcinoid disease (carcinoid syndrome). Symptoms of carcinoid syndrome include facial flushing, diarrhea, wheezing, colicky abdominal pain, and edema. Surgical resection offers the only curative treatment for neuroendocrine tumors, although peptide hormone analogues can be used to control carcinoid symptoms. Guidelines exist to determine when further surgical resection is required when NETs (carcinoids) are found incidentally during appendicectomy. A multi-disciplinary approach is essential for the management of all children with these rare and challenging tumors.

GSK-3β protein phosphorylates and stabilizes HLXB9 protein in insulinoma cells to form a targetable mechanism of controlling insulinoma cell proliferation

Insulinomas (pancreatic islet β cell tumors) are the most common type of functioning pancreatic neuroendocrine tumors that occur sporadically or as a part of the MEN1 syndrome that is caused by germ line mutations in MEN1. Tissue-specific tumor predisposition from germ line mutations in ubiquitously expressed genes such as MEN1 could occur because of functional consequences on tissue-specific factors. We previously reported the proapoptotic β cell differentiation factor HLXB9 as a downstream target of menin (encoded by MEN1). Here we show that GSK-3β inactivates the proapoptotic activity of HLXB9 by phosphorylating HLXB9 at Ser-78/Ser-80 (pHLXB9). Although HLXB9 is found in the nucleus and cytoplasm, pHLXB9 is predominantly nuclear. Both pHLXB9 and active GSK-3β are elevated in β cells with menin knockdown, in MEN1-associated β cell tumors (insulinomas), and also in human sporadic insulinomas. Pharmacologic inhibition of GSK-3β blocked cell proliferation in three different rodent insulinoma cell lines by arresting the cells in G2/M phase and caused apoptosis. Taken together, these data suggest that the combination of GSK-3β and pHLXB9 forms a therapeutically targetable mechanism of insulinoma pathogenesis. Our results reveal that GSK-3β and pHLXB9 can serve as novel targets for insulinoma treatment and have implications for understanding the pathways associated with β cell proliferation.

New insights into the role of chronic inflammation and cytokines in the etiopathogenesis of gastroenteropancreatic neuroendocrine tumors

Although previously considered rare, recent epidemiological studies have revealed that the incidence (3.6/100,000) and prevalence (35/100,000) of gastroenteropancreatic neuroendocrine tumors (GEP-NETs) has increased over the past few decades. Despite the progress in the understanding of GEP-NET molecular biology, there is still little advance in the early diagnosis due to lack of specific tumor markers. As the tumors are mostly detected in their late stage, they are not well controlled by either biotherapy or conventional chemotherapy, and thus represent a significant clinical issue. Chronic inflammation has been implicated in the development of GEP-NETs. This review presents recent findings that link pro-inflammatory cytokines to the molecular basis of GEP-NET tumorigenesis, leading to a more personalized approach to disease management and therapy.

Surgical management of pancreatic neuroendocrine neoplasms

Pancreatic neuroendocrine neoplasms are relatively rare entities, representing approximately 1% to 2% of all pancreatic tumors. Owing to their rarity as well as their relatively indolent natural history, treatment approaches are not yet standardized. A formal pancreatic resection is usually mandatory for large and localized sporadic pancreatic tumors or in the presence of symptoms. However, in small and asymptomatic lesions, a conservative approach consisting in a careful wait-and-see policy is going to appear as more appropriate, particularly when, to remove the lesion, an aggressive surgical procedure is required, such as pancreaticoduodenectomy or distal splenopancreatectomy, depending on the localization of the tumor. Surgery has also a significant role in locally advanced and metastatic forms. In the setting of MEN 1 syndrome or Von-Hippel Lindau disease, the tumor size and the possible symptoms should be considered in the evaluation of a proper treatment.

[Targeted therapies, prognostic and predictive factors in endocrine oncology]

A better understanding of molecular mechanisms responsible for tumorigenesis has allowed the development of targeted drugs designed to improve the outcome of cancer. In endocrine tumors, several molecules have demonstrated efficacy in terms of progression free survival during phase III trials such as vandetanib and cabozantinib in medullary thyroid carcinoma, sorafenib in differentiated thyroid carcinoma and everolimus or sunitinib for pancreatic neuroendocrine tumors. Rare cancer network has allowed ongoing phase III trials in malignant pheochromocytoma and adrenocortical carcinoma. However, to date no specific predictive biomarker has yet been identified for a personalized cancer medicine. We review recent advances in endocrine oncology concerning molecular targets identification, targeted therapies and predictive or prognostic markers.

Targeted therapy with kinase inhibitors in aggressive endocrine tumors

INTRODUCTION

Kinase inhibitors (KIs) are a class of anticancer drugs that inhibit activity of the enzymes protein kinases, which regulate crucial cellular processes and have a demonstrated role in human oncogenesis. Treatment of advanced forms of endocrine cancer which are not responsive to cytotoxic chemotherapies is challenging and use of KIs is gaining a growing role in this field.

AREAS COVERED

The authors summarize the main genetic alterations known to be linked to endocrine tumors, indicating the rationale for utilizing KIs. Furthermore, they present an updated analysis of clinical trials available on PubMed Central, which were pertinent to the activities of KIs in aggressive endocrine cancer. The authors also discuss the adverse effects of KIs and summarize likely involved underlying mechanisms.

EXPERT OPINION

KIs are effective in obtaining a radiological disease control and an improvement of progression-free survival in several forms of endocrine cancer but will never deliver a knockout blow of the disease, due to mechanisms of adaptation to circumvent the specific molecular blockade. The new frontier of KIs treatment is to identify agents that could synergize activity of KIs. The true goal will be to perform an overall genotyping of each tumor, thus predicting the impact of combined targeted therapies in the context of a particular constellation of mutant genes.

Zollinger-Ellison syndrome: classical considerations and current controversies

Zollinger-Ellison syndrome (ZES) is an endocrinopathy characterized by gastrin-secreting tumors, responsible for causing the formation of multiple, refractory, and recurrent peptic ulcers in the distal duodenum and proximal jejunum. Two main variants have been described, sporadic and those found in association with parathyroid and pituitary tumors, a genetic disorder known as multiple endocrine neoplasia-1 (MEN-1). Biochemical serum evaluation for elevated gastrin, followed by radiological or nuclear localization of the primary lesion, is mandated for establishing diagnosis. The mainstays of treatment include management of hypersecretory state with medical suppression of gastric acid production and surgical resection of primary tumor for the prevention of malignant transformation and metastatic complications. Medical therapy with proton pump inhibitors has virtually eliminated the need for acid-reducing surgical procedures. Surgical approach to sporadic and MEN-1-associated ZES varies based on our understanding of the natural history of the condition and the probability of cure; however, resection to a negative microscopic margin is indicated in both cases. Postoperative surveillance involves measurement of gastrin level, followed by imaging if elevation is detected. Re-excision of recurrent or resection of metastatic disease is a subject of controversy; however, at the present time aggressive cytoreductive approach is favored.

Zollinger-Ellison syndrome: recent advances and controversies

PURPOSE OF REVIEW

To review the recent advances and current controversies in patients with Zollinger-Ellison syndrome (ZES).

RECENT FINDINGS

Recent advances in the management of ZES include: improved understanding of the pathogenesis of gastrinoma and pancreatic neuroendocrine tumors, new prognostic classification systems, new diagnostic algorithms, more sensitive localization studies, new treatment strategies including improved control of gastric acid secretion and role for surgery, and new approaches to patients with advanced disease. Controversies include: the best approach to a patient with hypergastrinemia suspected of possibly having ZES, the appropriate gastrin assay to use, the role of surgery in patients with ZES, especially those with multiple endocrine neoplasia type 1, and the precise order of therapeutic modalities in the treatment of patients with advanced disease.

SUMMARY

This review updates clinicians regarding important advances and controversies required to optimally diagnose and manage patients with ZES.

Quality of life, resource utilisation and health economics assessment in advanced neuroendocrine tumours: a systematic review

Neuroendocrine tumours (NET) are often diagnosed at an advanced stage when the prognosis is poor for patients, who often experience diminished quality of life (QoL). As new treatments for NET become available, it is important to characterise the associated outcomes, costs and QoL. A comprehensive search was performed to systematically review available data in advanced NET regarding cost of illness/resource utilisation, economic studies/health technology assessment and QoL. Four rounds of sequential review narrowed the search results to 22 relevant studies. Most focused on surgical procedures and diagnostic tools and contained limited information on the costs and consequences of medical therapies. Multiple tools are used to assess health-related QoL in NET, but few analyses have been conducted to assess the comparative impact of available treatment alternatives on QoL. Limitations include English language and the focus on advanced NET; ongoing terminology and classification changes prevented pooled statistical analyses. This systematic review suggests a lack of comparative economic and outcomes data associated with NET treatments. Further research on disease costs, resource utilisation and QoL for patients with advanced NET is warranted.

Emerging therapies and latest development in the treatment of unresectable pancreatic neuroendocrine tumors: an update for clinicians

Pancreatic neuroendocrine tumors (pNETs) differ in their clinical behavior, presentation and prognosis based on their initial histological features and disease stage. While small resectable tumors can be treated surgically, metastatic and locally advanced disease carries a significant mortality and treatment options have been limited in terms of their efficacy. Streptozocin-based regimens were the only agents available before but recent advances have improved the armamentarium to treat pNETs. Newer chemotherapeutic agents such as temozolomide, somatostatin analogs and targeted therapies including everolimus and sunitinib are now available to treat these tumors. Several combination regimens with targeted therapies and newer agents such as pazopanib are being developed and tested in ongoing trials.

Pancreatic neuroendocrine neoplasms: diagnosis and management

Pancreatic neuroendocrine neoplasms are uncommon but rising in incidence. There have been recent changes in the WHO nomenclature and a newly proposed American Joint Committee on Cancer TNM staging, which complement each other. These neoplasms are of great medical and radiological interest because of their diverse presenting features and imaging appearances. There is an increased role for both anatomic and functional imaging in the assessment of these neoplasms. A review of the nomenclature, staging, and imaging is presented in this paper.

Animal models and cell lines of pancreatic neuroendocrine tumors

Pancreatic neuroendocrine tumors (PNETs), also known as islet cell tumors, are mostly indolent neoplasms that probably arise from a network of endocrine cells that includes islet cells and pluripotent precursors in the pancreatic ductal epithelium. The incidence and prevalence of PNETs continue to rise in recent years because of more sensitive detection. The molecular pathogenesis, early detection, molecular predictors of tumor behavior, and targeted drug therapy of PNETs are not well understood and require additional basic and translational research. The rarity and indolent nature of these tumors, difficulty of access to appropriate patient tissue samples, and varying histopathology and secreted hormones pose particular challenges to PNET researchers. Animal models and cell lines are indispensable tools for investigating the pathogenesis, pathophysiology, mechanisms for tumor invasion and metastasis, and therapeutics of PNETs. This review summarizes currently available animal models and cell lines of PNETs, which have provided valuable insights into the pathogenesis and natural history of human PNETs. In the future, animal models and cell lines of PNETs should also be used to study early tumor detection and molecular predictors of tumor behavior and to test the responses to, and mechanisms for, novel targeted drug therapies.

Translational research in endocrine surgery

This article reviews translational research in endocrine surgery, with a focus on disorders of the thyroid, parathyroids, adrenals, and endocrine pancreas. Discovery of genes responsible for heritable endocrine cancer syndromes has increased knowledge of the causes and mechanisms of endocrine cancer and has refined surgical treatment options. Knowledge of mutations in sporadic cancer has led to rapid progress in small-molecule kinase inhibitor strategies. These breakthroughs and their influence on current therapy are discussed to provide surgeons with an overview of the basic science research currently creating new clinical treatments and improving patient care.

Comparison of WHO Classifications (2004, 2010), the Hochwald grading system, and AJCC and ENETS staging systems in predicting prognosis in locoregional well-differentiated pancreatic neuroendocrine tumors

It is difficult to predict prognosis in patients with locoregional well-differentiated (WD) pancreatic neuroendocrine tumors (PanNET). We aimed to examine commonly used stratification systems [World Health organization (WHO) 2004 and 2010 classifications, American Joint Committee on Cancer (AJCC) and European Neuroendocrine Tumor Society (ENETS) staging, and the Hochwald grading system] for their power in predicting recurrence-free survival (RFS) in these patients. Seventy-five such patients (mean age 56 y, mean follow-up 79 mo) who underwent resection with sufficient tissue material and follow-up data were studied. RFS was correlated with variable clinicopathologic features and stratified with above-mentioned systems. Concordance index (CI) was then calculated. With the WHO 2004 classification, 16, 35, and 24 PanNETs were classified as benign behavior, uncertain behavior, and WD endocrine carcinoma, respectively. By the WHO 2010 classification, 26, 41, and 8 tumors were grade 1, 2, and 3, respectively. Using the Hochwald system, 47 were low grade, and 28 were intermediate grade. The AJCC staging information was complete for 62 patients (13 had the lymph node status Nx) and included: stages IA (19/62), IB (10/62), IIA (10/62), and IIB (23/62). The ENETS staging information was stages I (16/62), IIa (8/62), IIb (14/62), IIIa (0/62), and IIIb (24/62). The average Ki-67 proliferation index (PI) was 8.1%. Factors that predicted RFS included tumor size, nodal metastasis, vascular invasion, perineural invasion, necrosis, mitosis, and Ki-67 PI (all P<0.01). The CI for each system was: 0.6361 for WHO 2004, 0.6735 for WHO 2010, 0.6495 for AJCC staging, 0.6642 for ENETS staging, and 0.6851 for the Hochwald grading system. When these systems were analyzed in conjunction with various additional important pathologic features, combination of the Hochwald grading system and Ki-67 PI achieved the highest CI (0.7946). Therefore, although all these systems predict RFS well in locoregional WD PanNETs, the Hochwald grading system achieves the highest predictive ability. Further predictive power can be achieved by combining the Hochwald grading system and Ki-67 PI.

A differential diagnosis of inherited endocrine tumors and their tumor counterparts

Inherited endocrine tumors have been increasingly recognized in clinical practice, although some difficulties still exist in differentiating these conditions from their sporadic endocrine tumor counterparts. Here, we list the 12 main topics that could add helpful information and clues for performing an early differential diagnosis to distinguish between these conditions. The early diagnosis of patients with inherited endocrine tumors may be performed either clinically or by mutation analysis in at-risk individuals. Early detection usually has a large impact in tumor management, allowing preventive clinical or surgical therapy in most cases. Advice for the clinical and surgical management of inherited endocrine tumors is also discussed. In addition, recent clinical and genetic advances for 17 different forms of inherited endocrine tumors are briefly reviewed.

Clinical pathways for pancreatic neuroendocrine tumors

BACKGROUND

Pancreatic neuroendocrine tumors (PNETs) represent a group of diseases that pose diagnostic and therapeutic challenges due to their clinical and pathological heterogeneity as well as the limited number of patients available for clinical trials. Over the last couple of decades, a major progress in understanding tumor biology led to the discovery of new potential targets for the medical treatment of these tumors.

DISCUSSION

There are numerous novel targeted agents in various stages of preclinical and clinical development that offer considerable promise as monotherapy or combination therapy for PNETs. The question of whether traditional clinical research methods are appropriate for the development of novel, targeted anticancer agents has been the subject of many discussions. Major challenges include identifying a valid target, the most effective agent within a target class, the right subset of population to benefit from the drug, and the most appropriate setting to use the drug. As new agents emerge, oncologists are faced with making clinical decisions sometimes before having a high level of evidence. In this review, we attempt to address some of the management steps involved in treating patients with pancreatic neuroendocrine tumors, particularly well to moderately differentiated tumors. The purpose of this review is to offer a therapeutic sequence including surgery, liver-directed therapy, chemotherapy, and targeted therapy for this disease.

Management of pancreatic neuroendocrine tumors

Pancreatic neuroendocrine tumors account for 1% to 2% of pancreatic neoplasms and may occur sporadically or as part of a hereditary syndrome. Patients may present with symptoms related to hormone secretion by functional tumors or to locally advanced or metastatic nonfunctional tumors. Asymptomatic pancreatic neuroendocrine tumors are increasingly detected incidentally during abdominal imaging performed for other reasons. The management of localized pancreatic neuroendocrine tumors is surgical resection. Hepatic metastases are common and their management involves a variety of liver-directed therapies, which should be tailored according to extent of disease, symptoms, presence of extrahepatic metastases, and patient performance status.

PI3K/Akt/mTOR pathway inhibitors in the therapy of pancreatic neuroendocrine tumors

The phosphatidylinositol 3-kinase (PI3K)/Akt/mammalian target of rapamycin (mTOR) pathway is implicated in the pathogenesis of pancreatic neuroendocrine tumors (pNETs). Activation of this pathway is driven by aberrant tyrosine kinase receptor activities. Mutations in the PI3K/Akt/mTOR pathway occur in 15% of pNETs, and expression of genes of the PI3K/Akt/mTOR pathway is altered in the majority of pNETs. The mTOR inhibitor everolimus has been approved by the FDA for the treatment of pNET, but its efficacy may be limited by its inability to prevent mTORC2-mediated activation of Akt. Specific inhibitors of PI3K, Akt, or other pathway nodes, and their concomitant use with mTOR inhibitors, or agents with dual activity, may be more effective. Preclinical studies demonstrate that inhibitors of the PI3K pathway have antitumor activity in pNET cells, either through direct inhibition of individual pathway nodes or indirect inhibition of molecular chaperones such as heat-shock protein 90. Clinical studies are underway evaluating individual node and dual node inhibitors.

Pharmacotherapy of Zollinger-Ellison syndrome

INTRODUCTION

The role of pharmacotherapy in the management of patients with Zollinger-Ellison syndrome (ZES) is often equated with the medical management of acid hypersecretion. However, pharmacotherapy is also increasingly involved in the other management areas of these patients.

AREAS COVERED

This paper reviews the role of pharmacotherapy in all aspects of the management of patients with ZES. Newer aspects are emphasized. This includes the difficulty of diagnosing ZES in patients taking proton pump inhibitors. Also covered is the role of pharmacotherapy in controlling acid hypersecretion and other hormonal hypersecretory states these patients may develop, including hyperparathyroidism in patients with multiple endocrine neoplasia type 1 and ZES; tumor localization; and the treatment of advanced metastatic disease. The last includes chemotherapy, liver-directed therapies, biotherapy (somatostatin/interferon), peptide radio-receptor therapy and molecular-targeted therapies including the use of mTor inhibitors (everolimus) and tyrosine kinase inhibitors (sunitinib).

EXPERT OPINION

Pharmacotherapy is now involved in all aspects of the management of patients with ZES, with the result that ZES has progressed from being considered an entirely surgical disease initially to the present where medical treatment plays a major role in almost all aspects of the management of these patients.

The embryonic transcription factor Hlxb9 is a menin interacting partner that controls pancreatic β-cell proliferation and the expression of insulin regulators

The multiple endocrine neoplasia type 1 (MEN1) syndrome is caused by germline mutations in the MEN1 gene encoding menin, with tissue-specific tumors of the parathyroids, anterior pituitary, and enteropancreatic endocrine tissues. Also, 30-40% of sporadic pancreatic endocrine tumors show somatic MEN1 gene inactivation. Although menin is expressed in all cell types of the pancreas, mouse models with loss of menin in either pancreatic α-cells, or β-cells, or total pancreas develop β-cell-specific endocrine tumors (insulinomas). Loss of widely expressed tumor suppressor genes may produce tissue-specific tumors by reactivating one or more embryonic-specific differentiation factors. Therefore, we determined the effect of menin overexpression or knockdown on the expression of β-cell differentiation factors in a mouse β-cell line (MIN6). We show that the β-cell differentiation factor Hlxb9 is posttranscriptionally upregulated upon menin knockdown, and it interacts with menin. Hlxb9 reduces cell proliferation and causes apoptosis in the presence of menin, and it regulates genes that modulate insulin level. Thus, upon menin loss or from other causes, dysregulation of Hlxb9 predicts a possible combined mechanism for β-cell proliferation and insulin production in insulinomas. These observations help to understand how a ubiquitously expressed protein such as menin might control tissue-specific tumorigenesis. Also, our findings identify Hlxb9 as an important factor for β-cell proliferation and insulin regulation.

Insulinoma and anaesthetic implications

Insulinoma is a rare neuroendocrine tumour of the pancreas , which is usually small, solitary and benign. It may be part of the multiple endocrine neoplasia type 1 syndrome. It is diagnosed by clinical, biochemical and imaging modalities. Hypoglycaemic symptoms can be medically controlled by diazoxide or somatostatin analogues. Localisation of the tumour is a challenge to clinicians. Surgical resection is the curative treatment with a high success rate. Intraoperatively, ultrasound and surgical palpation help to confirm the site of tumour. Intraoperatively, maintenance of optimum glucose levels is of main concern because there may be severe hypoglycemia while handling the tumour, symptoms of which remain masked under general anaesthesia. Glucose infusion and frequent plasma glucose monitoring to maintain plasma glucose level more than 60 mg/dL is found to be helpful. We performed a systematic search in PubMed, Cochrane Library and also in Google. We used the following text words for our search: Insulinoma, neuro-endocrine tumors, multiple endocrine neoplasia, hypoglycemia, anaesthetic management of insulinoma, glucose management. In this article, we review the incidence and epidemiology of insulinoma, its clinical features, diagnosis, localisation and treatment, with special emphasis on anaesthetic management.

Pancreatic neuroendocrine tumors: clinical features, diagnosis and medical treatment: advances

Pancreatic neuroendocrine tumors (pNETs) comprise with gastrointestinal carcinoids, the main groups of gastrointestinal neuroendocrine tumors (GI-NETs). Although these two groups of GI-NETs share many features including histological aspects; over-/ectopic expression of somatostatin receptors; the ability to ectopically secrete hormones/peptides/amines which can result in distinct functional syndromes; similar approaches used for tumor localization and some aspects of treatment, it is now generally agreed they should be considered separate. They differ in their pathogenesis, hormonal syndromes produced, many aspects of biological behaviour and most important, in their response to certain anti-tumour treatment (chemotherapy, molecular targeted therapies). In this chapter the clinical features of the different types of pNETs will be considered as well as aspects of their diagnosis and medical treatment of the hormone-excess state. Emphasis will be on controversial areas or recent advances. The other aspects of the management of these tumors (surgery, treatment of advanced disease, tumor localization) are not dealt with here, because they are covered in other chapters in this volume.

A new double substitution mutation in the MEN1 gene: a limited penetrance and a specific phenotype

Multiple endocrine neoplasia type 1 (MEN1) is an autosomal-dominant cancer syndrome that is caused by a germline mutation in the MEN1 gene encoding a tumour-suppressor protein, menin. MEN1 causes a combination of endocrine tumours such as parathyroid adenomas, pituitary adenomas, glucagonomas, gastrinomas, insulinomas, adrenocortical adenomas and non-endocrine tumours. We here present a large MEN1 family where the carriers developed mild hyperparathyroidism, multiple well-differentiated functionally active neuroendocrine tumours of the pancreas and no pituitary tumour. The causal mutation is a new double substitution in the coding region of exon 2 in the MEN1 gene c.[428T>A; 429C>T], p.Leu143His. This new mutation in the MEN1 gene is clinically relevant leading to a limited penetrance and specific phenotype.

Importance of surveillance for multiple endocrine neoplasia-1 and surgery in patients with sporadic Zollinger-Ellison syndrome

BACKGROUND & AIMS

Zollinger-Ellison syndrome (ZES) is a rare disorder characterized by gastrin-secreting tumors of the gastrointestinal tract and gastric acid hypersecretion. There is controversy over the best way to manage these patients; we investigated outcomes of patients with different forms of the disease, who did and did not undergo surgery.

METHODS

We performed a retrospective chart review of patients with ZES associated with multiple endocrine neoplasia type 1 (MEN-1) (n = 16) and those with sporadic ZES (n = 33) seen at a tertiary care center from August 1994 to January 2012. Cox proportional hazards modeling was used to compare survival times among groups, based on treatment with surgery (n = 34) and the presence of MEN-1 (n = 9 with surgery; n = 7 without surgery). Differences were compared using the unpaired Student t test and the Fisher exact test.

RESULTS

Patients with MEN-1 syndrome-associated ZES presented at a younger age than patients with sporadic ZES (34.9 vs 45.7 y, respectively; P < .05) and were diagnosed at a younger age (39.3 vs 49.7 y, respectively; P < .01), yet lived a similar number of years (55.9 vs 55.1 y, respectively; P = .91). None of the patients with MEN-1-associated ZES died of progressive disease, compared with 86% of deaths among patients with sporadic ZES (P < .05). Lymph node involvement, detected during surgery, increased the risk of metastasis to liver (P = .13) and lack of cure by surgery (P = .01). Surgery reduced all-cause mortality (hazard ratio, 0.11; 95% confidence interval, 0.2-0.6; P = .011) and disease-related mortality (hazard ratio, 0.14; 95% confidence interval, 0.2-0.84; P = .032) of patients with sporadic, but not MEN-1 syndrome-associated, ZES.

CONCLUSIONS

The presence of MEN-1 is associated with earlier onset and diagnosis of ZES, but a benign clinical course that rarely results in disease-related death; surgery therefore can be deferred for these patients. However, 86% of deaths among patients with sporadic ZES are attributed to disease-related causes, and mortality is reduced by early surgical intervention. Patients with sporadic ZES should undergo surgery soon after diagnosis.

Diagnosis of Zollinger-Ellison syndrome: Increasingly difficult

In the present paper the increasing difficulty of diagnosis of Zollinger-Ellison syndrome (ZES) due to issues raised in two recent papers is discussed. These issues involve the difficulty and need to withdraw patients suspected of ZES from treatment with Proton Pump Inhibitors (omeprazole, esomeprazole, lansoprazole, rabeprazole, pantoprazole) and the unreliability of many gastrin radioimmunoassays. The clinical context of each of these important issues is reviewed and the conclusions in these articles commented from the perspective of clinical management.

Neuroendocrine tumor disease: an evolving landscape

Gastroenteropancreatic neuroendocrine neoplasms (GEP-NENs) represent a heterogenous group of tumors arising from a variety of neuroendocrine cell types. The incidence and prevalence of GEP-NENs have markedly increased over the last three decades. Symptoms are often absent in early disease, or vague and nonspecific even in advanced disease. Delayed diagnosis is thus common. Chromogranin A is the most commonly used biomarker but has limitations as does the proliferative marker Ki-67%, which is often used for tumor grading and determination of therapy. The development of a multidimensional prognostic nomogram may be valuable in predicting tumor behavior and guiding therapy but requires validation. Identification of NENs that express somatostatin receptors (SSTR) allows for SSTR scintigraphy and positron emission tomography imaging using novel radiolabeled compounds. Complete surgical resection of limited disease or endoscopic ablation of small lesions localized in stomach or rectum can provide cure; however, the majority of GEP-NENs are metastatic (most frequently the liver and/or mesenteric lymph nodes) at diagnosis. Selected patients with metastatic disease may benefit from advanced surgical techniques including hepatic resection or liver transplantation. Somatostatin analogs are effective for symptomatic treatment and exhibit some degree of antiproliferative activity in small intestinal NENs. There is a place for streptozotocin, temozolomide, and capecitabine in the management of pancreatic NENs, while new agents targeting either mTOR (everolimus) or angiogenic (sunitinib) pathways have shown efficacy in these lesions.

Place of surgical resection in the treatment strategy of gastrointestinal neuroendocrine tumors

Neuroendocrine tumors (NET) are usually slow-growing neoplasms carrying an overall favorable prognosis. Surgery, from resection to transplantation, remains the only potential curative option for these patients, and should always be considered. Nevertheless, because of very few randomized controlled trials available, the optimal treatment for these patients remains controversial, especially regarding the place of surgery. We herein discuss the place of surgical resection in the treatment strategy in neuroendocrine tumors of the digestive tract.

Molecular pathology and genetics of pancreatic endocrine tumours

Pancreatic neuroendocrine tumours (PETs) are the second most frequent pancreatic neoplasms. Their poor chemosensitivity, high rate of metastatic disease and relatively long survival make PETs an ideal field to be explored for novel therapies based on specific molecular changes. PETs are generally sporadic but can also arise within hereditary syndromes, such as multiple endocrine neoplasia type 1, von Hippel-Lindau, neurofibromatosis type 1 and tuberous sclerosis complex, which represent a model for sporadic cases too. Among allelic imbalances, main genomic changes involve gain of 17q, 7q and 20q and loss of 11q, 6q and 11p, which identify regions of putative candidate oncogenes or tumour suppressor genes (TSGs), respectively, sometime with potential prognostic significance. Overexpression of Src-like kinases and cyclin D1 (CCND1) oncogene has been described. As for TSGs, P53 (TP53), DPC4/SMAD4 and RB (RB1) are not implicated in PET tumorigenesis, while for p16INK4a (CDKN2A), TIMP3, RASSF1A and hMLH1, more data are available, suggesting a role for methylation as a silencing mechanism. In the last decade, gene expression profile studies, analysis of microRNAs and, more recently, large-scale mutational analysis have highlighted commonly altered molecular pathways in the pathology of PETs. The roles of the mammalian target of rapamycin pathway, and its connection with Src kinases, and the activity of a number of tyrosine kinase receptors seem to be pivotal, as confirmed by the results of recent clinical trials with targeted agents. Mutations of DAXX and ATRX are common and related to altered telomeres but not to prognosis.

A case of pancreatic neuroendocrine tumor in a patient with neurofibromatosis-1

Patients with neurofibromatosis-1 (NF-1) sometime develop neuroendocrine tumors (NET). Although these NETs usually occur in the duodenum or peri-ampullary region, they occasionally grow in the pancreas (PNET). A 62-year-old man with NF-1 had mild liver dysfunction and was admitted to our hospital for further examination. An abdominal contrast-enhanced computed tomography scan demonstrated a 30-mm tumor in the head of the pancreas. The scan showed an invasion of the tumor into the duodenum, and biopsy under an endoscopic ultrasonography indicated that the tumor was a NET. A subtotal stomach-preserving pancreaticoduodenectomy was performed. Macroscopically, the pancreatic tumor was white and elastic hard. Microscopically, tumor cells were composed of ribbons, cords, and solid nests with an acinus-like structure. The tumor was diagnosed as NET G2 according to the WHO classification (2010). The product of the NF-1 gene, i.e., neurofibromin, was weakly positive in the tumor cells, suggesting that the tumor was induced by a mutation in the NF-1 gene. This is the seventh case of PNET arising in NF-1 patients worldwide.

Hereditary pancreatic cancer: molecular bases and their application in diagnosis and clinical management: a guideline of the TTD group

Pancreatic carcinoma (PC) represents the fourth leading cause of cancer death in Spain with a death rate of 2,400 males and 2,000 females per year. Poor outcome related to its silent nature and the lack of reliable secondary prevention measures translate into advanced-stage diagnosis, 75 % of deaths within the first year of diagnosis and 5-year survival rate of <5 %. Family history was first recognized as a risk factor for PC. Further population-based and case-control studies subsequently found that 7.8 % of patients with PC have a family history of the same tumor and individuals with a first-degree relative with PC have a 3.2-fold increased risk of developing PC. Overall, it is estimated that up to 10 % of PC have a familial component. However, known genetic syndromes account for <20 % of the observed familial aggregation of PC. We review the most important aspects in epidemiology, molecular biology and clinical management of familial PC.

Pancreatic lesions in von Hippel-Lindau disease? A systematic review and meta-synthesis of the literature

BACKGROUND

von Hippel-Lindau (vHL) disease is a rare condition that leads to characteristic lesions within many different body systems. Pancreatic manifestations of vHL cover a wide spectrum of pathologies, and thus, accurate characterization and management is critical.

METHODS

A comprehensive and systematic text word and MeSH search of the medical literature was performed to identify studies where information regarding the prevalence, clinical characteristics, and management recommendations could be extracted.

RESULTS

Eleven studies were identified but 2 studies utilized the same data set. Of the 10 remaining studies, a total of 1,442 patients with vHL were available for analysis. Four hundred and twenty patients were examined for any type of pancreatic lesion, 362 for simple cysts or serous cystadenomas (SCAs), and 1,442 for neuroendocrine tumors (NETs). Of the 420 assessed for any pancreatic manifestation of vHL, 252 (60%) had a pancreatic lesion identified. Simple cysts that present as the sole manifestation of pancreatic disease were common and found in 169 of 362 (47%) patients. These are usually asymptomatic and do not normally require intervention. SCAs were reported in 39 of 362 (11%) patients and followed a similar benign course; resection is acceptable in symptomatic patients. NETs were identified in 211 of 1,442 (15%) patients, and 27 of 1,442 (2%) lesions behaved malignantly. Management of NETs depends on size, doubling time, and underlying genetics. Renal cell carcinoma is a characteristic in vHL, but there were no cases of pancreatic metastases identified from the included studies. Adenocarcinomas of the pancreas are not pathogenically linked to vHL.

CONCLUSIONS

This review highlights the wide spectrum and high prevalence of pancreatic lesions in vHL. Simple cysts and SCAs are benign, but NETs require careful observation due to their malignant potential.

Pancreatic endocrine neoplasms: a current update on genetics and imaging

Pancreatic endocrine neoplasms are rare pancreatic tumours that may occur sporadically or as part of inherited syndromes such as multiple endocrine neoplasia-1 syndrome, von Recklinghausen disease, von Hippel-Lindau syndrome and tuberous sclerosis complex. Recent advances in the genetics and pathology of hereditary syndromes have provided valuable insights into the pathophysiology and biology of sporadic pancreatic endocrine neoplasms. Evolving molecular data on the biology of these neoplasms have the potential for diagnostic, therapeutic and prognostic use.

Pancreatic neuroendocrine tumors: a comprehensive review

Pancreatic neuroendocrine tumors (NETs) are a heterogeneous group of tumors. Despite being relatively rare, representing just 1-2% of all pancreatic neoplasms, the incidence of pancreatic NET has increased over the past two decades. Although the primary treatment for localized NET is surgical resection, there is still a lack of effective therapeutic options for patients with advanced unresectable pancreatic NET. Recently, the targeted agents sunitinib malate (SUTENT®, Pfizer Inc, NYC) and everolimus (AFINITOR®, Novartis, Basel, Switzerland)-both with different mechanisms of action-received United States Food and Drug Administration approval for the treatment of progressive, well-differentiated, pancreatic NET in patients with unresectable, locally advanced or metastatic disease. SUTENT® also received approval for this indication by the European Commission in 2010. Our article presents an overview of pancreatic NET, with a focus on their diagnostic work-up, clinical presentation and treatment options. Topics for further investigation of targeted therapy are also discussed.

Treatment of advanced pancreatic neuroendocrine tumors: potential role of everolimus

Pancreatic neuroendocrine tumors (PanNETs) are frequently diagnosed at unresectable stage and remain a medical challenge. Everolimus (RAD001, Afinitor^®, Novartis, Basel, Switzerland), an orally administered inhibitor of mammalian target of rapamycin (mTOR), was recently approved by the Food and Drug Administration to treat patients with advanced PanNETs. This review will examine the mechanism of action of everolimus, the function of mTOR and its inhibition, PanNETs and the mTOR pathway, and clinical trials of everolimus in PanNETs. Future investigations will focus on everolimus combination therapy to treat PanNETs and the discovery of predictive biomarkers for response to everolimus.

New strategies for advanced neuroendocrine tumors in the era of targeted therapy

Low- to intermediate-grade neuroendocrine tumor (NET) constitutes a group of indolent malignancies that share the capacity for secreting hormones and neuroamines. Until recently, there were few therapeutic options for oncologic control. The PROMID study showed that octreotide long-acting repeatable formulation can delay tumor growth in midgut NETs. And, recent phase III studies showed both everolimus and sunitinib improved progression-free survival in pancreatic NETs, validating the phosphoinositide 3-kinase/Akt/mTOR pathway and angiogenesis as important targets for further advances. Ongoing and planned pivotal studies targeting these pathways in other NET subtypes may widen their therapeutic application. Development of rational combinations may further improve therapeutic outcome. These successes and our improved understanding of the underlying molecular biology are likely to lead to further important advances on the horizon.