Meningiomas may be a component tumor of multiple endocrine neoplasia type 1

Rare germline mutations in cyclin-dependent kinase inhibitor genes in multiple endocrine neoplasia type 1 and related states

CONTEXT

Germline mutation in the MEN1 gene is the usual cause of multiple endocrine neoplasia type 1 (MEN1). However, the prevalence of identifiable germline MEN1 mutations in familial MEN1 cases is only 70%. Some cases may have a germline mutation in another gene such as the p27 cyclin-dependent kinase inhibitor (CDKI).

OBJECTIVE

The aim of the study was to investigate cases of MEN1 or related states for germline mutations in all CDKI genes.

METHODS

A total of 196 consecutive index cases were selected with clear or suspected MEN1 and no identifiable germline MEN1 mutation. Every case was analyzed for germline mutation in each of the seven CDKI genes.

RESULTS

We identified benign polymorphisms of the CDKI genes and also 15 other initially unclassified sequence variants. After detailed gene/protein analysis, seven of these 15 variants were classified as probably pathological mutations. Three of these seven were probable mutations of p27. The remaining four were probable pathological mutations in three of the other CDKI genes, thereby implicating these three genes in the germline of human tumors. The identification rates for probably pathological mutations among the 196 index cases were similarly low for each of four CDKI genes: p15 (1%), p18 (0.5%), p21 (0.5%), and p27 (1.5%). No characteristic clinical subtype related to MEN1 was identified among the seven index cases and their families.

CONCLUSION

Rare germline mutation in any among four (p15, p18, p21, and p27) of the seven CDKIs is a probable cause of MEN1 or of some related states.

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

Pancreatic endocrine tumors (PETs) can occur as part of 4 inherited disorders, including Multiple Endocrine Neoplasia type 1 (MEN1), von Hippel-Lindau disease (VHL), neurofibromatosis 1 (NF-1) (von Recklinghausen disease), and the tuberous sclerosis complex (TSC). The relative frequency with which patients who have these disorders develop PETs is MEN1>VHL>NF-1>TSC. Over the last few years, there have been major advances in the understanding of the genetics and molecular pathogenesis of these disorders as well in the localization and the medical and surgical treatment of PETs in such patients. The study of PETs in these disorders not only has provided insights into the possible pathogenesis of sporadic PETs but also has presented several unique management and treatment issues, some of which are applicable to patients with sporadic PETs. Therefore, the study of PETs in these uncommon disorders has provided valuable insights that, in many cases, are applicable to the general group of patients with sporadic PETs. In this article, these areas are reviewed briefly along with the current state of knowledge of the PETs in these disorders, and the controversies that exist in their management are summarized briefly and discussed.

Multiple endocrine neoplasia syndromes

The multiple endocrine neoplasia (MEN) syndromes are rare autosomal-dominant conditions that predispose affected individuals to benign and malignant tumors of the pituitary, thyroid, parathyroids, adrenals, endocrine pancreas, paraganglia, or nonendocrine organs. The classic MEN syndromes include MEN type 1 and MEN type 2. However, several other hereditary conditions should also be considered in the category of MEN: von Hippel-Lindau syndrome, the familial paraganglioma syndromes, Cowden syndrome, Carney complex, and hyperparathyroidism jaw-tumor syndrome. In addition, researchers are becoming aware of other familial endocrine neoplasia syndromes with an unknown genetic basis that might also fall into the category of MEN. This article reviews the clinical features, diagnosis, and surgical management of the various MEN syndromes and genetic risk assessment for patients presenting with one or more endocrine neoplasms.

Nesidioblastosis and hyperplasia of alpha cells, microglucagonoma, and nonfunctioning islet cell tumor of the pancreas: review of the literature

We report a rare case of nesidioblastosis and hyperplasia of alpha cells, microglucagonoma, and nonfunctioning islet cell tumor of the pancreas. The patient's clinical presentation, diagnosis, treatment, pancreas pathology, and follow-up are reviewed. A 60-year-old patient was incidentally found to harbor a pancreatic mass with markedly elevated glucagon levels but without glucagonoma syndrome. She was initially diagnosed with glucagonoma, and the tumor was resected. Pathological examination demonstrated that the tumor was a nonfunctioning islet cell tumor and revealed nesidioblastosis and hyperplasia of alpha cells and microglucagonoma in the apparently normal surgical margin. The patient still had high postoperative glucagons levels which were suppressed by somatostatin analog treatment. No pancreatic tumors recurred 36 months after surgery. This is the third case of alpha-cell nesidioblastosis reported in the English literature. Nesidioblastosis and hyperplasia of alpha cells should be considered in the differential diagnosis of hyperglucagonemia. Somatostatin analog may be used to suppress glucagon secretion in alpha-cell hyperplasia.

Molecular genetics of meningiomas: from basic research to potential clinical applications

To review our current understanding of the molecular pathogenesis of meningiomas, to suggest topics for future investigations, and to present perspectives for clinical application. Significant progress has been made in recent years in delineating the molecular mechanisms involved in meningioma formation, growth, and malignant progression. However, many questions remain unanswered. Mutations in the NF2 gene probably account for the formation of more than half of all meningiomas. On the other hand, the molecular events underlying the initiation of meningiomas without NF2 mutations have yet to be identified. Investigating hereditary conditions associated with an increased meningioma incidence and the mechanisms underlying the development of radiation-induced meningiomas could potentially yield relevant insights. Meningioma growth is sustained by the dysregulated expression of steroid hormones, growth factors, their receptors, and activation of signal transduction cascades. The underlying genetic causes are unknown. Malignant progression of meningiomas probably involves the inactivation of tumor suppressor genes on chromosomes 1p, 9p, 10q, and 14q. However, with the possible exception of INK4A/INK4B, the actual targets of these chromosomal losses have remained largely elusive. Cell cycle dysregulation and telomerase activation have been recognized as important steps in meningioma progression. Telomere dynamics, cell cycle control, and the mechanisms responsible for deoxyribonucleic acid damage control are tightly interwoven. Investigating genes involved in the maintenance of genomic integrity might significantly deepen the understanding of meningioma progression. An area that has received relatively little attention thus far is the genetic background of meningioma spread and invasion. Possible clinical applications of the molecular data available may include a meningioma grading system based on genetic alterations, as well as therapeutic strategies for refractory meningiomas aimed at interfering with signal transduction pathways.

Histological classification and molecular genetics of meningiomas

Meningiomas account for up to 30% of all primary intracranial tumours. They are histologically classified according to the World Health Organization (WHO) classification of tumours of the nervous system. Most meningiomas are benign lesions of WHO grade I, whereas some meningioma variants correspond with WHO grades II and III and are associated with a higher risk of recurrence and shorter survival times. Mutations in the NF2 gene and loss of chromosome 22q are the most common genetic alterations associated with the initiation of meningiomas. With increase in tumour grade, additional progression-associated molecular aberrations can be found; however, most of the relevant genes are yet to be identified. High-throughput techniques of global genome and transcriptome analyses and new meningioma models provide increasing insight into meningioma biology and will help to identify common pathogenic pathways that may be targeted by new therapeutic approaches.

Mechanisms of disease: multiple endocrine neoplasia type 1-relation to chromatin modifications and transcription regulation

Multiple endocrine neoplasia type 1 (MEN1) is a hereditary tumor syndrome characterized by tumors of the parathyroid glands, the pancreatic islets, the pituitary gland, the adrenal glands, as well as by neuroendocrine carcinoid tumors, often at a young age. Causal to the syndrome are germline mutations of the MEN1 tumor-suppressor gene. Identification of gene-mutation carriers has enabled presymptomatic diagnosis and treatment of MEN1-related lesions. The product of the MEN1 gene is the nuclear protein menin. Recent observations indicate several functions for menin in the regulation of transcription, serving either as a repressor or as an activator: menin interacts with the activator-protein-1-family transcription factor JunD, changing it from an oncoprotein into a tumor-suppressor protein, putatively by recruitment of histone deacetylase complexes; menin maintains transforming growth factor beta mediated signal transduction involved in parathyroid hormone and prolactin gene expression; and menin is an integral component of histone methyltransferase complexes. In this capacity menin is a regulator of expression of the cyclin-dependent-kinase inhibitors p18INK4C and p27Kip1; furthermore, menin serves as a co-activator of estrogen receptor mediated transcription, by recruiting methyltransferase activity to lysine 4 of histone 3 at the estrogen responsive TFF1(pS2) gene promoter. We propose that menin links transcription-factor function to histone-modification pathways and that this is crucial for MEN1 tumorigenesis. Understanding the molecular pathology of MEN1 tumorigenesis will lead to new therapeutic strategies.

Serum gastrin in Zollinger-Ellison syndrome: II. Prospective study of gastrin provocative testing in 293 patients from the National Institutes of Health and comparison with 537 cases from the literature. evaluation of diagnostic criteria, proposal of new criteria, and correlations with clinical and tumoral features

In two-thirds of patients with Zollinger-Ellison syndrome (ZES), fasting serum gastrin (FSG) levels overlap with values seen in other conditions. In these patients, gastrin provocative tests are needed to establish the diagnosis of ZES. Whereas numerous gastrin provocative tests have been proposed, only the secretin, calcium, and meal tests are widely used today. Many studies have analyzed gastrin provocative test results in ZES, but they are limited by small patient numbers and methodologic differences. To address this issue, we report the results of a prospective National Institutes of Health (NIH) study of gastrin provocative tests in 293 patients with ZES and compare these data with those from 537 ZES and 462 non-ZES patients from the literature. In 97%-99% of gastrinoma patients, an increase in serum gastrin post secretin (Delta secretin) or post calcium (Delta calcium) occurred. In NIH ZES patients with <10-fold increase in FSG, the sensitivity/specificity of the widely used criteria were as follows: Delta secretin > or =200 pg/mL (83%/100%), Delta secretin >50% (86%/93%), Delta calcium > or =395 pg/mL (54%/100%), and Delta calcium >50% (78%/83%). A systematic analysis of the sensitivity and specificity of other possible criteria for a positive secretin or calcium test allowed us to identify a new criterion for secretin testing (Delta > or =120 pg/mL) with the highest sensitivity/specificity (94%/100%) and to confirm the commonly used criterion for calcium tests (Delta > or =395 pg/mL) (62%/100%). This analysis further showed that the secretin test was more sensitive than the calcium test (94% vs. 62%). Our results suggest that secretin stimulation should be used as the first-line provocative test because of its greater sensitivity and simplicity and lack of side effects. In ZES patients with a negative secretin test, 38%-50% have a positive calcium test. Therefore the calcium test should be considered in patients with a strong clinical suspicion of ZES but a negative secretin test. Furthermore, we found that some clinical (diarrhea, duration of medical treatment), laboratory (basal acid output), and tumoral (size, extent) characteristics correlate with the serum gastrin increase post secretin and post calcium. However, using the proposed criteria, the result of these provocative tests (that is, positive or negative) is minimally influenced by these factors, so secretin and calcium provocative tests are reliable in patients with different clinical, laboratory, and tumor characteristics. A systematic analysis of meal testing showed that 54%-77% of ZES patients have a <50% postprandial serum gastrin increase. However, 9%-20% of ZES patients had a >100% increase post meal, causing significant overlap with antral syndromes. Furthermore, we could not confirm the usefulness of meal tests for localization of duodenal gastrinomas. We conclude that the secretin test is a crucial element in the diagnosis of most ZES patients, the calcium test may be useful in selected patients, but the meal test is not helpful in the management of ZES. For secretin testing, the criterion with the highest sensitivity and specificity is an increase of > or =120 pg/mL, which should replace other criteria commonly used today.

Serum gastrin in Zollinger-Ellison syndrome: I. Prospective study of fasting serum gastrin in 309 patients from the National Institutes of Health and comparison with 2229 cases from the literature

The assessment of fasting serum gastrin (FSG) is essential for the diagnosis and management of patients with the Zollinger-Ellison syndrome (ZES). Although many studies have analyzed FSG levels in patients with gastrinoma, limited information has resulted from these studies because of their small size, different methodologies, and lack of correlations of FSG levels with clinical, laboratory, or tumor features in ZES patients. To address this issue, we report the results of a prospective National Institutes of Health (NIH) study of 309 patients with ZES and compare our results with those of 2229 ZES patients in 513 small series and case reports in the literature. In the NIH and literature ZES patients, normal FSG values were uncommon (0.3%-3%), as were very high FSG levels >100-fold normal (4.9%-9%). Two-thirds of gastrinoma patients had FSG values <10-fold normal that overlap with gastrin levels seen in more common conditions, like Helicobacter pylori infection or antral G-cell hyperplasia/hyperfunction. In these patients, FSG levels are not diagnostic of ZES, and gastrin provocative tests are needed to establish the diagnosis. Most clinical variables (multiple endocrine neoplasia type 1 status, presence or absence of the most common symptoms, prior medical treatment) are not correlated with FSG levels, while a good correlation of FSG values was found with other clinical features (prior gastric surgery, diarrhea, duration from onset to diagnosis). Increasing basal acid output, but not maximal acid output correlated closely with increasing FSG. Numerous tumoral features correlated with the magnitude of FSG in our study, including tumor location (pancreatic > duodenal), primary size (larger > smaller) and extent (liver metastases > local disease). In conclusion, this detailed analysis of FSG in a large number of patients with ZES allowed us to identify important clinical guidelines that should contribute to improved diagnosis and management of patients with ZES.

Recurrent cytogenetic aberrations in histologically benign, invasive meningiomas of the sphenoid region

Meningiomas that arise in the sphenoid region (MSR) often display growth patterns leading to widespread invasion and destruction of the surrounding structures. Consequently, there is still estimated recurrence rate up to 30% with MSR. Conventional cytogenetic studies have failed to reveal aberrations characteristic of invasive meningiomas. Here we investigated 10 invasive and 5 non-invasive MSR using the array-based comparative genomic hybridization (array-CGH) with the GenoSensor Array 300. Mean number of aberrations detected per tumor was significantly greater for invasive meningiomas-67.4 compared with 40.5 for non-invasive MSR. Additionally, invasive MSR disclosed frequent losses on 1p, 6q, 14q and gains on 15q and 20, which were identified previously as molecular hallmarks of stepwise meningioma progression. Thus, the presence of a complex cytogenetic profile and progression-associated chromosomal aberrations in benign MSR is associated with their increased invasive potential. Inasmuch as no reliable adjuvant therapy for recurrent meningiomas is available thus far, revealed genomic aberrations can provide a potential targets for drug discovery and therapeutic intervention in a future.

[Multiple endocrine neoplasia type 1 (MEN 1): clinical, biochemical and molecular diagnosis and treatment of the associated disturbances]

Multiple endocrine neoplasia (MEN) syndromes include types 1 (MEN 1) and 2 (MEN 2), von Hippel-Lindau syndrome, neurofibromatosis type 1 and Carney complex. These are complex genetic syndromes caused by activation or inactivation of different types of genes known to be involved in the regulation of cell proliferation. In this review we will discuss the clinical manifestations and management of the MEN 1 syndrome as well as the genetic screening of potential MEN 1 gene carriers. MEN 1 is a hereditary syndrome, transmitted in an autosomic dominant fashion and caused by an inactivating mutation of the MEN 1 gene, characterized by the development of primary hyperparathyroidism, islet cell tumors and pituitary adenomas. In addition, these patients can present with cutaneous manifestations such as angiofibromas and collagenomas, and can develop other neoplastic manifestations including carcinoids, thyroid tumors, adrenal adenomas, lipomas, pheochromocytomas and meningiomas. The MEN 1 gene encodes a peptide which is a tumor suppressor gene called menin. Several studies have demonstrated its importance in regulation of cell proliferation and have confirmed its role in the pathogenesis of the MEN 1 syndrome. The discovery of the MEN 1 gene and the genetic analysis of MEN 1 patients have resulted in earlier diagnosis and treatment of asymptomatic carriers which can potentially result in a longer survival of these patients. Further investigation of the function and signaling pathways of the menin protein will hopefully offer therapeutic alternatives to patients with malignant progression of MEN 1-related tumors and also result in improved survival.

Patients with multiple endocrine neoplasia type 1 with gastrinomas have an increased risk of severe esophageal disease including stricture and the premalignant condition, Barrett's esophagus

CONTEXT

Multiple endocrine neoplasia type 1 (MEN1) patients frequently develop Zollinger-Ellison syndrome (MEN1/ZES). Although esophageal reflux symptoms are common in these patients, little is known about long-term occurrence of severe peptic esophageal disease including strictures and Barrett's esophagus (BE).

OBJECTIVE

The objective of the study was to prospectively analyze the frequency of severe peptic esophageal disease in ZES patients with and without MEN1.

SETTING

The study was conducted at a tertiary care research center.

PATIENTS

Two hundred ninety-five patients (80 = MEN1/ZES, 215 = sporadic ZES) participated in a prospective study.

INTERVENTIONS AND OUTCOME MEASURES

Assessment of MEN1, acid hypersecretion, upper gastrointestinal endoscopy/biopsies, and tumor status were measured initially and at each follow-up. Esophageal manometry was performed in 89 patients. Frequency and type of esophageal disease were correlated with clinical/laboratory/tumoral features of ZES/MEN1.

RESULTS

In MEN1/ZES patients, esophageal stricture was 3-fold higher, BE 5-fold higher, and dysplasia 8-fold higher, and one patient died of esophageal adenocarcinoma. Esophageal symptoms were more frequent or severe in MEN1/ZES, but known risk factors for severe esophageal disease and ZES-specific features did not differ between MEN1/ZES and sporadic ZES. In MEN1/ZES, the onset of ZES was 10 yr earlier, and H2-antagonists were used longer and at lower doses. MEN1/ZES patients with esophageal disease differed from those without in that ZES diagnosis was delayed longer, esophageal symptoms were more frequent or severe, hiatal hernias were more frequent, esophagitis or pyloric scarring was more common, basal acid output was higher, and hyperparathyroidism was underdiagnosed.

CONCLUSIONS

This study shows that MEN1/ZES patients have a higher incidence of severe esophageal disease including the premalignant condition BE and identifies factors important for their pathogenesis that need to be incorporated into their long-term treatment.

Lessons from genes mutated in multiple endocrine neoplasia (MEN) syndromes

Multiple endocrine neoplasia (MEN) types 1 and 2 syndromes are rare hereditary cancer syndromes expressing a variety of endocrine and non-endocrine neoplasias and lesions. The improving of both molecular and clinical genetics knowledge helps health care providers in the whole spectrum of the clinical managements of MEN patients. The MEN1 gene, a tumour suppressor gene, is responsible of MEN1 syndrome, and is probably involved in the regulation of several cell functions, including DNA replication and repair and transcriptional machinery. RET proto-oncogene encodes for a receptor tyrosine kinase protein whose expression is fundamental for appropriate migration, development and differentiation of neuroendocrine cells originating from neural crest. Currently, DNA testing makes possible the early identification of germline mutation in asymptomatic mutant gene carriers in both MEN syndromes. Consequently, the combination of new genetic and diagnostic tools could permit a precocious detection of MEN-associated neoplasms, and in particular the identification of a strong genotype-phenotype correlations in MEN2 syndrome demonstrates an improving outcome and quality of life for affected subjects.

Hereditary hormone excess: genes, molecular pathways, and syndromes

Hereditary origin of a tumor helps toward early discovery of its mutated gene; for example, it supports the compilation of a DNA panel from index cases to identify that gene by finding mutations in it. The gene for a hereditary tumor may contribute also to common tumors. For some syndromes, such as hereditary paraganglioma, several genes can cause a similar syndrome. For other syndromes, such as multiple endocrine neoplasia 2, one gene supports variants of a syndrome. Onset usually begins earlier and in more locations with hereditary than sporadic tumors. Mono- or oligoclonal ("clonal") tumor usually implies a postnatal delay, albeit less delay than for sporadic tumor, to onset and potential for cancer. Hormone excess from a polyclonal tissue shows onset at birth and no benefit from subtotal ablation of the secreting organ. Genes can cause neoplasms through stepwise loss of function, gain of function, or combinations of these. Polyclonal hormonal excess reflects abnormal gene dosage or effect, such as activation or haploinsufficiency. Polyclonal hyperplasia can cause the main endpoint of clinical expression in some syndromes or can be a precursor to clonal progression in others. Gene discovery is usually the first step toward clarifying the molecule and pathway mutated in a syndrome. Most mutated pathways in hormone excess states are only partly understood. The bases for tissue specificity of hormone excess syndromes are usually uncertain. In a few syndromes, tissue selectivity arises from mutation in the open reading frame of a regulatory gene (CASR, TSHR) with selective expression driven by its promoter. Polyclonal excess of a hormone is usually from a defect in the sensor system for an extracellular ligand (e.g., calcium, glucose, TSH). The final connections of any of these polyclonal or clonal pathways to hormone secretion have not been identified. In many cases, monoclonal proliferation causes hormone excess, probably as a secondary consequence of accumulation of cells with coincidental hormone-secretory ability.

Meningioma: Current treatment options and future directions

Benign meningiomas can be observed if not symptomatic or growing. When treatment is indicated, the options are surgery, radiosurgery, fractionated radiation therapy, or a combination of these modalities. Except in certain cases, such as large tumors that require debulking for relief of symptoms, we do not recommend the routine use of combination therapy. Intracranial meningiomas have usually been treated with surgical resection with an expected durable local control of 80% to 90% when a gross total resection (GTR) is obtained. Patients who have inoperable disease, refuse surgery, undergo less than a GTR, or who have aggressive histology should instead be considered candidates for radiation therapy or radiosurgery. While benign meningiomas can be successfully treated definitively or postoperatively with either fractionated radiation therapy or single fraction radiosurgery, atypical or malignant lesions are best treated with fractionated radiation therapy with conventional dosimetric margins. The role of systemic therapy is not yet defined, but multiple agents are being investigated in early phase trials for patients with recurrent or progressive disease after standard therapy has failed.

Parathyroid adenoma and primary CNS tumors

Hyperparathyroidism onset at a young age is one feature in multiple endocrine neoplasia (MEN) type 1 and MEN type 2A cancer syndromes. There are several case reports of MEN Type 1-associated central nervous system (CNS) tumors. To determine if there is an association between parathyroid adenomas and CNS tumors, we used Swedish registry data to identify all individuals operated on for parathyroid adenomas between 1958-99 (n = 12,468). Follow-up for the occurrence of CNS tumors in these individuals was through linkage with the Swedish Cancer Registry. There were 70 observed cases of a CNS tumor diagnosed after a parathyroid adenoma, to be compared to 35 expected (standard incidence ratio [SIR] = 2.0; 95% confidence interval [CI] = 1.5-2.5). This increased risk was independent of duration of follow-up and was confined to meningiomas (SIR = 2.4, 95% CI = 1.7-3.4) and neurinomas (SIR = 3.4, 95% CI = 1.5-6.8). These results strongly indicate an association between these tumor forms that may be genetic, environmental (such as radiation) or a combination of both.