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Sunita K Agarwal - One of the best experts on this subject based on the ideXlab platform.
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The future: genetics advances in MEN1 therapeutic approaches and management strategies.
Endocrine-related cancer, 2017Co-Authors: Sunita K AgarwalAbstract:The identification of the multiple endocrine neoplasia type 1 (MEN1) gene in 1997 has shown that germline heterozygous mutations in the MEN1 gene located on chromosome 11q13, predisposes to the development of tumors in the MEN1 syndrome. Tumor development occurs upon loss of the remaining normal copy of the MEN1 gene in MEN1-target tissues. Therefore, MEN1 is a classic tumor suppressor gene in the context of MEN1. This tumor suppressor role of the protein encoded by the MEN1 gene, menin, holds true in mouse models with germline heterozygous MEN1 loss wherein MEN1-associated tumors develop in adult mice after spontaneous loss of the remaining non-targeted copy of the MEN1 gene. The availability of genetic testing for mutations in the MEN1 gene has become an essential part of the diagnosis and management of MEN1. Genetic testing is also helping to exclude mutation negative cases in MEN1 families from the burden of lifelong clinical screening. In the past 20 years, efforts of various groups world-wide have been directed at mutation analysis, molecular genetic studies, mouse models, gene expression studies, epigenetic regulation analysis, biochemical studies, and anti-tumor effects of candidate therapies in mouse models. This review will focus on the findings and advances from these studies to identify MEN1 germline and somatic mutations, the genetics of MEN1-related states, several protein partners of menin, the three-dimensional structure of menin, and menin-dependent target genes. The ongoing impact of all these studies on disease prediction, management and outcomes will continue in the years to come.
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Molecular Genetics of MEN1-Related Neuroendocrine Tumors
Diagnostic and Therapeutic Nuclear Medicine for Neuroendocrine Tumors, 2016Co-Authors: Sunita K AgarwalAbstract:Neuroendocrine tumors (NETs) are frequently observed in patients with the multiple endocrine neoplasia type 1 (MEN1) syndrome. The characteristic features of MEN1 include tumors in multiple endocrine glands – the parathyroids, pancreas, and pituitary. MEN1-related NETs include duodenal gastrinomas, pancreatic NETs (PNETs), and foregut NETs (gastric, thymic, or bronchial carcinoids). Heterozygous germline inactivating mutations in the MEN1 gene predisposes to tumor development in the specific target tissues that also show somatic loss of heterozygosity (LOH) of the MEN1 locus. MEN1 is inherited in an autosomal dominant manner and with high penetrance by age 50, but with no obvious genotype–phenotype correlation. MEN1 is a tumor suppressor gene that encodes a 610 amino acid protein – menin – that is multifunctional through its interactions with a variety of proteins. In mouse models, homozygous germline loss of MEN1 causes early embryonic death, and heterozygous germline loss of MEN1 mimics the pattern of endocrine tumor development seen in human MEN1. Studies in mouse models have revealed candidate genes that may affect the tumorigenesis of PNETs from menin loss. This chapter covers the genetic and molecular findings of MEN1-related NETs.
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A patient with MEN1 typical features and MEN2-like features
International journal of endocrine oncology, 2016Co-Authors: Diala El-maouche, Sunita K Agarwal, James Welch, Lee S. Weinstein, William F. Simonds, Stephen J. MarxAbstract:Multiple endocrine neoplasia (MEN) type 1 (MEN1) and 2 (MEN2) rarely co-exist in one case. Here we report a patient with features of both syndromes. The patient presented with typical MEN1 features plus pheochromocytoma and thickened corneal nerves. She had a germline 1132delG frameshift mutation in MEN1, no mutation in CDKN1B (p27) and no RET mutation, but had both RET polymorphisms Gly691Ser and Arg982Cys. This is the first case report of a combination of typical clinical findings of MEN1 harboring a germline MEN1 mutation and the MEN2-like phenotype with negative full RET gene analysis of pathogenic variants. Possible explanations include a previously unrecognized phenotype–genotype association or the influence of potential phenotypic modifying RET variants. Furthermore, the combination observed in this patient may point to a single molecular pathway, and supports the possibility of as yet unrecognized connections between the molecular pathways for MEN1/menin protein and MEN2/RET protein.
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The MEN1 gene and pituitary tumours.
Hormone Research in Paediatrics, 2009Co-Authors: Sunita K Agarwal, Carmen M Mateo, Atsushi Ozawa, Stephen J. MarxAbstract:Sporadic multiple endocrine neoplasia type 1 (MEN1) is defined as the occurrence of tumours in two of three main endocrine tissue types: parathyroid, pituitary and pancreaticoduodenal. A prolactinoma variant or Burin variant of MEN1 was found to occur in three large kindreds, with more prolactinomas and fewer gastrinomas than typical MEN1. MEN1 tumours differ from common tumours by showing features from the MEN1 gene (e.g. larger pituitary tumours). They also show various expressions of tumour multiplicity; however, pituitary tumour in MEN1 is usually solitary. Diagnosis in MEN1 carriers during childhood is not directed at cancers but at benign morbid tumours. Morbid prolactinoma occurred at the age of 5 years in one MEN1 individual; hence, this is the earliest age at which to recommend tumour surveillance in carriers. The MEN1 gene shows biallelic inactivation in 30% of some types of common variety endocrine tumours (e.g. parathyroid adenoma, gastrinoma, insulinoma and bronchial carcinoid), but in only 1-5% of common pituitary tumours. Heterozygous knockout of MEN1 in mice provides a robust model of MEN1 and has been found to support further research on anti-angiogenesis therapy for pituitary tumours. The rarity of MEN1 mutations in some MEN1-like states aids the identification of other mutated genes, such as AIP, HRPT2 and p27(Kip1). We present recent clinical and basic findings about the MEN1 gene, particularly concerning hereditary vs. common variety pituitary tumours.
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parathyroid tumor development involves deregulation of homeobox genes
Endocrine-related Cancer, 2008Co-Authors: Hc Jennifer Shen, Jennifer E Rosen, Lauren M Yang, Carmen M Mateo, Sunita K Agarwal, Allen M. Spiegel, Settara C. Chandrasekharappa, Lee A Burns, Sharon A. Savage, Francis S. CollinsAbstract:Multiple endocrine neoplasia type 1 (MEN1) is an autosomal dominant syndrome caused by mutations in the MEN1 tumor suppressor gene. Loss of the functional second copy of the MEN1 gene causes individuals to develop multiple endocrine tumors, primarily affecting the parathyroid, pituitary, and pancreas. While it is clear that the protein encoded by MEN1, menin, suppresses endocrine tumors, its biochemical functions and direct downstream targets remain unclear. Recent studies have suggested that menin may act as a scaffold protein to coordinate gene transcription, and that menin is an oncogenic cofactor for homeobox (HOX) gene expression in hematopoietic cancer. The role of HOX genes in adult cell differentiation is still obscure, but growing evidence suggests that they may play important roles in the development of cancer. Therefore, we hypothesized that specific HOX genes were regulated by menin in parathyroid tumor development. Utilizing quantitative TaqMan RT-PCR, we compared expression profiles of the 39 HOX genes in human familial MEN1 (fMEN1) parathyroid tumors and sporadic parathyroid adenomas with normal samples. We identified a large set of 23 HOX genes whose deregulation is specific for fMEN1 parathyroid tumors, and only 5 HOX genes whose misexpression are specific for sporadic parathyroid tumor development. These findings provide the first evidence that loss of the MEN1 tumor suppressor gene is associated with deregulation of specific HOX gene expression in the development of familial human parathyroid tumors. Our results strongly reinforce the idea that abnormal expression of developmental HOX genes can be critical in human cancer progression.
Stephen J. Marx - One of the best experts on this subject based on the ideXlab platform.
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children with MEN1 gene mutations may present first and at a young age with cushing disease
Clinical Endocrinology, 2018Co-Authors: Angeliki Makri, Maria Belen Bonella, Margaret F Keil, Laura C Hernandezramirez, Gabriella Paluch, Amit Tirosh, Carolina Saldarriaga, Prashant Chittiboina, Stephen J. MarxAbstract:Objective Cushing disease (CD) is a rare entity caused by ACTH-secreting pituitary tumours, leading to prolonged hypercortisolism. Most cases are sporadic but can rarely occur in the context of familial predisposition, due to germline mutations in genes such as MEN1, leading to multiple endocrine neoplasia type 1, MEN1. We have reported previously that CD can be the first and only presenting manifestation of MEN1. In this report, we describe a cohort of paediatric patients who presented with CD as the first manifestation of MEN1. Materials and methods A retrospective analysis of paediatric patients admitted to the National Institutes of Health (NIH) Clinical Center for evaluation of hypercortisolism, between 1997 and 2017. MEN1 was diagnosed on a clinical, familial and/or genetic basis. Results Of a total of 238 children with CD, six patients were subsequently diagnosed with MEN1, three males and three females with a mean age at diagnosis of CD at 13.4 ± 2.9 years. Five of the six patients had familial MEN1 and one patient was a sporadic case. Additional manifestations of MEN1 included primary hyperparathyroidism in three patients and hyperprolactinemia in two patients. Discussion This report describes a paediatric patient population with MEN1 in whom CD was the initial manifestation, confirming a previous observation that paediatric patients with MEN1 may present first with an ACTH-producing adenoma. Therefore, germline MEN1 mutations should be sought in paediatric CD and tested for when there is a suggestive family history and/or other manifestations.
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Recent Topics Around Multiple Endocrine Neoplasia Type 1
The Journal of clinical endocrinology and metabolism, 2018Co-Authors: Stephen J. MarxAbstract:Introduction Multiple endocrine neoplasia type 1 (MEN1) is complex with regard to clinical expressions, management, and molecular pathways. Advances are being made broadly and in focused aspects. Selected topics are presented for their developments since publication of the most recent MEN1 consensus guidelines 6 years ago. Methods Topics were selected for clinical impact or broad interest or both. For each topic, information was obtained from original reports and reviews. Results The selected topics are as follows: tumor behavior and breast cancer in MEN1; foregut neuroectoderm tumor screening, biomarkers periodically to detect tumor emergence of foregut neuroectoderm tumors, 68Ga dotatate positron emission tomography/computed tomography for pancreatic and duodenal neuroectodermal tumor imaging, and glucagon-like peptide-1 receptor scintigraphy for insulinoma; therapy, the size of pancreatic neuroendocrine tumor (NET) as one criterion for surgery, minimally invasive surgery of pancreatic NETs, and 177Lu dotatate therapy; MEN1 gene, the search for the MEN1/menin pathway and MEN1 or GCM2 mutation in familial isolated hyperparathyroidism, and MEN1 mutation-positive vs mutation-negative cases of MEN1 are different. Conclusions MEN1 topics are a rich and fast-moving area. Important highlights stand out, and major and rapid advances will continue into the near future.
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familial hyperparathyroidism disorders of growth and secretion in hormone secretory tissue
Hormone and Metabolic Research, 2017Co-Authors: Stephen J. Marx, Delmar M LourencoAbstract:Six syndromes of familial hyperparathyroidism are compared: 1) Familial hypocalciuric hypercalcemia (FHH) expresses primary hyperparathyroidism (PHPT) beginning at birth with lifelong hypercalcemia. There is nonsuppressed PTH secretion from outwardly normal parathyroid glands. It reflects germline heterozygous mutation in CASR, GNA11, or AP2S1 . 2) Neonatal severe primary hyperparathyroidism is severest of the six syndromes. It requires urgent total parathyroidectomy in infancy. It usually reflects biallelic inactivation of the CASR. 3) Multiple endocrine neoplasia type 1 (MEN1) is most frequently expressed as PHPT with asymmetric enlargement of 3–4 parathyroids. Benign or malignant tumors may occur among 30 other tissues. It is predisposed by germline inactivation of MEN1 or rarely by inactivation of a cyclin dependent kinase inhibitor, and then termed MEN4. 4) Multiple endocrine neoplasia type 2A from RET activating mutation rarely presents as familial hyperparathyroidism, because medullary thyroid cancer and pheochromocytoma are more prominent. 5) Hyperparathyroidism-jaw tumor syndrome (HPT-JT) has frequent PHPT and benign jaw tumors. Twenty percent develop parathyroid cancer. It is predisposed by inactivating mutation in CDC73 . 6) Familial isolated hyperparathyroidism causes multiple parathyroid tumors. It can be an incomplete expression of FHH, MEN1, HPT-JT or even of relatives without a shared driver mutation. However, in 20% of families it reflects GCM2 activating mutation. Five of the PHPT syndromes reflect overgrowth of parathyroid tissue; in contrast, familial hypocalciuric hypercalcemia reflects dysregulation of PTH secretion with little or no parathyroid overgrowth. These differences underlie major differences in clinical expression.
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A patient with MEN1 typical features and MEN2-like features
International journal of endocrine oncology, 2016Co-Authors: Diala El-maouche, Sunita K Agarwal, James Welch, Lee S. Weinstein, William F. Simonds, Stephen J. MarxAbstract:Multiple endocrine neoplasia (MEN) type 1 (MEN1) and 2 (MEN2) rarely co-exist in one case. Here we report a patient with features of both syndromes. The patient presented with typical MEN1 features plus pheochromocytoma and thickened corneal nerves. She had a germline 1132delG frameshift mutation in MEN1, no mutation in CDKN1B (p27) and no RET mutation, but had both RET polymorphisms Gly691Ser and Arg982Cys. This is the first case report of a combination of typical clinical findings of MEN1 harboring a germline MEN1 mutation and the MEN2-like phenotype with negative full RET gene analysis of pathogenic variants. Possible explanations include a previously unrecognized phenotype–genotype association or the influence of potential phenotypic modifying RET variants. Furthermore, the combination observed in this patient may point to a single molecular pathway, and supports the possibility of as yet unrecognized connections between the molecular pathways for MEN1/menin protein and MEN2/RET protein.
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The MEN1 gene and pituitary tumours.
Hormone Research in Paediatrics, 2009Co-Authors: Sunita K Agarwal, Carmen M Mateo, Atsushi Ozawa, Stephen J. MarxAbstract:Sporadic multiple endocrine neoplasia type 1 (MEN1) is defined as the occurrence of tumours in two of three main endocrine tissue types: parathyroid, pituitary and pancreaticoduodenal. A prolactinoma variant or Burin variant of MEN1 was found to occur in three large kindreds, with more prolactinomas and fewer gastrinomas than typical MEN1. MEN1 tumours differ from common tumours by showing features from the MEN1 gene (e.g. larger pituitary tumours). They also show various expressions of tumour multiplicity; however, pituitary tumour in MEN1 is usually solitary. Diagnosis in MEN1 carriers during childhood is not directed at cancers but at benign morbid tumours. Morbid prolactinoma occurred at the age of 5 years in one MEN1 individual; hence, this is the earliest age at which to recommend tumour surveillance in carriers. The MEN1 gene shows biallelic inactivation in 30% of some types of common variety endocrine tumours (e.g. parathyroid adenoma, gastrinoma, insulinoma and bronchial carcinoid), but in only 1-5% of common pituitary tumours. Heterozygous knockout of MEN1 in mice provides a robust model of MEN1 and has been found to support further research on anti-angiogenesis therapy for pituitary tumours. The rarity of MEN1 mutations in some MEN1-like states aids the identification of other mutated genes, such as AIP, HRPT2 and p27(Kip1). We present recent clinical and basic findings about the MEN1 gene, particularly concerning hereditary vs. common variety pituitary tumours.
Zhengping Zhuang - One of the best experts on this subject based on the ideXlab platform.
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cutaneous tumors in patients with multiple endocrine neoplasia type 1 show allelic deletion of the MEN1 gene
Journal of Investigative Dermatology, 1998Co-Authors: Svetlana Pack, Monica C Skarulis, Zhengping Zhuang, Stephen J. Marx, Maria L Turner, Alexander O Vortmeyer, R Boni, Thomas N DarlingAbstract:Multiple endocrine neoplasia type 1 (MEN1), the heritable tendency to develop tumors of the parathyroid, pituitary, and entero-pancreatic endocrine tissues, is the consequence of a germline mutation in the MEN1 gene. Endocrine tumors in these patients result when the mutant MEN1 allele is accompanied by loss of the normal MEN1 allele. Recently it was reported that MEN1 patients also exhibit several cutaneous tumors, including multiple angiofibromas, collagenomas, and lipomas. The purpose of this study was to examine skin lesions from patients with MEN1 for allelic loss of the MEN1 gene. Skin lesions from five patients with MEN1 were examined using fluorescence in situ hybridization. Six angiofibromas, three collagenomas, and one lipoma showed allelic deletion of the MEN1 gene. Allelic deletion was not observed in a melanocytic nevus or acrochordon from patients with MEN1. It was also not observed in an angiofibroma from a patient with tuberous sclerosis. These results suggest that loss of function of the wild-type MEN1 gene product plays a role in the development of angiofibromas, collagenomas, and lipomas in patients with MEN1.
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Mutations of the MEN1 Tumor Suppressor Gene in Pituitary Tumors
Cancer research, 1997Co-Authors: Zhengping Zhuang, Sunita K Agarwal, Svetlana Pack, Alexander O Vortmeyer, Shereen Ezzat, Robert J. Weil, Edward H. Oldfield, Won Sang Park, Steve Huang, Siradanahalli C. GuruAbstract:Although pituitary adenomas are monoclonal proliferations, somatic mutations involving genes that govern cell proliferation or hormone production have been difficult to identify. The genetic etiology of most pituitary tumors, therefore, remains unknown. Pituitary adenomas can develop sporadically or as a part of multiple endocrine neoplasia type 1 (MEN1). Recently, the gene responsible for MEN1 was cloned. To elucidate the potential etiological role of the MEN1 gene in pituitary tumorigenesis, 39 sporadic pituitary adenomas from 38 patients and 1 pituitary adenoma from a familial MEN1 patient were examined for MEN1 gene mutations and allelic deletions. Four of 39 sporadic pituitary adenomas showed a deletion of one copy of the MEN1 gene, and a specific MEN1 gene mutation in the remaining gene copy was detected in 2 of these tumors. The corresponding germ-line sequence was normal in all sporadic cases. A specific MEN1 mutation was detected in a pituitary adenoma and corresponding germ-line DNA in a patient with familial MEN1. An allelic deletion of the remaining copy of the MEN1 gene was also found in the patient's tumor. Genetic alterations of the MEN1 gene represent a candidate pathogenetic mechanism of pituitary tumorigenesis. The data suggest that somatic MEN1 gene mutations and deletions play a causative role in the development of a subgroup of sporadic pituitary adenomas.
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Identification of MEN1 Gene Mutations in Sporadic Carcinoid Tumors of the Lung
Human molecular genetics, 1997Co-Authors: Larisa V Debelenko, Sunita K Agarwal, Mary Beth Kester, Irina A Lubensky, Zhengping Zhuang, Siradanahalli C. Guru, Elisabeth Brambilla, Jennifer I. Swalwell, Pachiappan ManickamAbstract:Lung carcinoids occur sporadically and rarely in association with multiple endocrine neoplasia type 1 (MEN1). There are no well defined genetic abnormalities known to occur in these tumors. We studied 11 sporadic lung carcinoids for loss of heterozygosity (LOH) at the locus of the MEN1 gene on chromosome 11q13, and for mutations of the MEN1 gene using dideoxy fingerprinting. Additionally, a lung carcinoid from a MEN1 patient was studied. In four of 11 (36%) sporadic tumors, both copies of the MEN1 gene were inactivated. All four tumors showed the presence of a MEN1 gene mutation and loss of the other allele. Observed mutations included a 1 bp insertion, a 1 bp deletion, a 13 bp deletion and a single nucleotide substitution affecting a donor splice site. Each mutation predicts truncation or potentially complete loss of menin. The remaining seven tumors showed neither the presence of a MEN1 gene mutation nor 11q13 LOH. The tumor from the MEN1 patient showed LOH at chromosome 11q13 and a complex germline MEN1 gene mutation. The data implicate the MEN1 gene in the pathogenesis of sporadic lung carcinoids, representing the first defined genetic alteration in these tumors.
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Somatic mutations of the MEN1 tumor suppressor gene in sporadic gastrinomas and insulinomas
Cancer research, 1997Co-Authors: Zhengping Zhuang, Sunita K Agarwal, Larisa V Debelenko, Svetlana Pack, Alexander O Vortmeyer, Won Sang Park, Steve Huang, Thu Anh Pham, Chaoyu Wang, Mary Beth KesterAbstract:Gastrinomas and insulinomas are frequent in multiple endocrine neoplasia type 1 (MEN1). The MEN1 tumor suppressor gene was recently identified. To elucidate the etiological role of the MEN1 gene in sporadic enteropancreatic endocrine tumorigenesis, we analyzed tumors (28 gastrinomas and 12 insulinomas) from 40 patients for MEN1 gene mutations and allelic deletions. One copy of the MEN1 gene was found to be deleted in 25 of 27 (93%) sporadic gastrinomas and in 6 of 12 (50%) sporadic insulinomas. MEN1 gene mutations were identified in 9 of 27 (33%) sporadic gastrinomas and 2 of 12 (17%) insulinomas and were not seen in corresponding germ-line DNA sequence. A specific MEN1 mutation was detected in one gastrinoma and in the corresponding germ-line DNA of a patient who had no family history of MEN1. Somatic MEN1 gene mutations and deletions play a critical role in the tumorigenesis of sporadic gastrinomas and may also contribute to the development of a subgroup of insulinomas.
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germline mutations of the MEN1 gene in familial multiple endocrine neoplasia type 1 and related states
Human Molecular Genetics, 1997Co-Authors: Sunita K Agarwal, Mary Beth Kester, Larisa V Debelenko, Christina Heppner, Michael R Emmertbuck, Monica C Skarulis, John L Doppman, Young S Kim, Irina A Lubensky, Zhengping ZhuangAbstract:Familial multiple endocrine neoplasia type 1 (FMEN1) is an autosomal dominant trait characterized by tumors of the parathyroids, gastro-intestinal endocrine tissue, anterior pituitary and other tissues. We recently cloned the MEN1 gene and confirmed its identity by finding mutations in FMEN1. We have now extended our mutation analysis to 34 more unrelated FMEN1 probands and to two related states, sporadic MEN1 and familial hyperparathyroidism. There was a high prevalence of heterozygous germline MEN1 mutations in sporadic MEN1 (8/11 cases) and in FMEN1 (47/50 probands). One case of sporadic MEN1 was proven to be a new MEN1 mutation. Eight different mutations were observed more than once in FMEN1. Forty different mutations (32 FMEN1 and eight sporadic MEN1) were distributed across the MEN1 gene. Most predicted loss of function of the encoded menin protein, supporting the prediction that MEN1 is a tumor suppressor gene. No MEN1 germline mutation was found in five probands with familial hyperparathyroidism, suggesting that familial hyperparathyroidism often is caused by mutation in another gene or gene(s).
Rajesh V Thakker - One of the best experts on this subject based on the ideXlab platform.
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multiple endocrine neoplasia type 1 MEN1 phenocopy due to a cell cycle division 73 cdc73 variant
Journal of the Endocrine Society, 2020Co-Authors: Kate E Lines, Lisa B Nachtigall, Laura E Dichtel, Treena Cranston, Hannah Boon, Xun Zhang, Kreepa Kooblall, Mark Stevenson, Rajesh V ThakkerAbstract:Multiple endocrine neoplasia type 1 (MEN1) is an autosomal dominant disorder characterized by the combined occurrence of parathyroid tumors, pituitary adenomas, and pancreatic neuroendocrine neoplasms (PNENs). MEN1 is caused by germline MEN1 mutations in > 75% of patients, and the remaining 25% of patients may have mutations in unidentified genes or represent phenocopies with mutations in genes such as cell cycle division 73 (CDC73), the calcium sensing receptor (CASR), and cyclin-dependent kinase inhibitor 1B (CDKN1B), which are associated with the hyperparathyroidism-jaw tumor syndrome, familial hypocalciuric hypercalcemia type 1, and MEN4, respectively. Here, we report a heterozygous c.1138C>T (p.Leu380Phe) CDC73 germline variant in a clinically diagnosed MEN1 patient, based on combined occurrence of primary hyperparathyroidism, acromegaly, and a PNEN. Characterization of the PNEN confirmed it was a neuroendocrine neoplasm as it immuno-stained positively for chromogranin and glucagon. The rare variant p.Leu380Phe occurred in a highly conserved residue, and further analysis using RNA-Scope indicated that it was associated with a significant reduction in CDC73 expression in the PNEN. Previously, CDC73 mutations have been reported to be associated with tumors of the parathyroids, kidneys, uterus, and exocrine pancreas. Thus, our report of a patient with PNEN and somatotrophinoma who had a CDC73 variant, provides further evidence that CDC73 variants may result in a MEN1 phenocopy.
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Current and emerging therapies for PNETs in patients with or without MEN1
Nature Reviews Endocrinology, 2018Co-Authors: Morten Frost, Kate E Lines, Rajesh V ThakkerAbstract:Pancreatic neuroendocrine tumours (PNETs) might occur as a non-familial isolated endocrinopathy or as part of a complex hereditary syndrome, such as multiple endocrine neoplasia type 1 (MEN1). MEN1 is an autosomal dominant disorder characterized by the combined occurrence of PNETs with tumours of the parathyroids and anterior pituitary. Treatments for primary PNETs include surgery. Treatments for non-resectable PNETs and metastases include biotherapy (for example, somatostatin analogues, inhibitors of receptors and monoclonal antibodies), chemotherapy and radiological therapy. All these treatments are effective for PNETs in patients without MEN1; however, there is a scarcity of clinical trials reporting the efficacy of the same treatments of PNETs in patients with MEN1. Treatment of PNETs in patients with MEN1 is challenging owing to the concomitant development of other tumours, which might have metastasized. In recent years, preclinical studies have identified potential new therapeutic targets for treating MEN1-associated neuroendocrine tumours (including PNETs), and these include epigenetic modification, the β-catenin–wingless (WNT) pathway, Hedgehog signalling, somatostatin receptors and MEN1 gene replacement therapy. This Review discusses these advances. Patients with multiple endocrine neoplasia type 1 (MEN1) can develop hormone-secreting and non-hormone-secreting tumours in endocrine organs, including in the pancreas, which decreases their life expectancy substantially Pancreatic neuroendocrine tumours (PNETs) in patients with MEN1 are especially difficult to treat owing to differences in growth potential, concomitant development of other tumours and relative insensitivity to treatment Current medical, surgical and radiological treatments for MEN1-related PNETs have not been formally assessed but instead have been used on the basis of their effects on PNETs in patients without MEN1 Therapies targeting MEN1-related tumours are required, and preclinical studies indicate that gene therapy, epigenetic modifiers, and wingless (WNT) pathway and vascular endothelial growth factor (VEGF)-signalling antagonists might be promising treatments Chemoprevention aimed at reducing or delaying the occurrence of MEN1-related PNETs might be possible by chronic administration of somatostatin analogues, which have anti-proliferative and anti-secretory actions The treatment of pancreatic neuroendocrine tumours (PNETs) in patients with multiple endocrine neoplasia type 1 (MEN1) is challenging. Here, Thakker and colleagues discuss the current and emerging therapies to treat PNETs in patients with or without MEN1.
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molecular genetics of syndromic and non syndromic forms of parathyroid carcinoma
Human Mutation, 2017Co-Authors: Luis Alberto Granado Cardoso, Mark Stevenson, Rajesh V ThakkerAbstract:Parathyroid carcinoma (PC) may occur as part of a complex hereditary syndrome or an isolated (i.e. non-syndromic) non-hereditary (i.e. sporadic) endocrinopathy. Studies of hereditary, and syndromic forms of PC, which include the hyperparathyroidism-jaw tumour syndrome (HPT-JT), multiple endocrine neoplasia types 1 and 2 (MEN1 and MEN2), and familial isolated primary hyperparathyroidism (FIHP), have revealed some genetic mechanisms underlying PC. Thus, cell division cycle 73 (CDC73) germline mutations cause HPT-JT, and CDC73 mutations occur in 70% of sporadic PC, but in only ∼2% of parathyroid adenomas. Moreover, CDC73 germline mutations occur in 20–40% of patients with sporadic PC and may reveal unrecognized HPT-JT. This indicates that CDC73 mutations are major driver mutations in the aetiology of PCs. However, there is no genotype-phenotype correlation and some CDC73 mutations (e.g. c.679_680insAG) have been reported in patients with sporadic PC, HPT-JT, or FIHP. Other genes involved in sporadic PC include germline MEN1 and rearranged during transfection (RET) mutations and somatic alterations of the retinoblastoma 1 (RB1) and tumour protein P53 (TP53) genes, as well as epigenetic modifications including DNA methylation and histone modifications, and microRNA mis-regulation. This review summarizes the genetics and epigenetics of the familial syndromic and non-syndromic (sporadic) forms of PC. This article is protected by copyright. All rights reserved
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multiple endocrine neoplasia type 1 MEN1 and type 4 men4
Molecular and Cellular Endocrinology, 2014Co-Authors: Rajesh V ThakkerAbstract:Multiple endocrine neoplasia (MEN) is characterized by the occurrence of tumors involving two or more endocrine glands within a single patient. Four major forms of MEN, which are autosomal dominant disorders, are recognized and referred to as: MEN type 1 (MEN1), due to menin mutations; MEN2 (previously MEN2A) due to mutations of a tyrosine kinase receptor encoded by the rearranged during transfection (RET) protoncogene; MEN3 (previously MEN2B) due to RET mutations; and MEN4 due to cyclin-dependent kinase inhibitor (CDNK1B) mutations. Each MEN type is associated with the occurrence of specific tumors. Thus, MEN1 is characterized by the occurrence of parathyroid, pancreatic islet and anterior pituitary tumors; MEN2 is characterized by the occurrence of medullary thyroid carcinoma (MTC) in association with phaeochromocytoma and parathyroid tumors; MEN3 is characterized by the occurrence of MTC and phaeochromocytoma in association with a marfanoid habitus, mucosal neuromas, medullated corneal fibers and intestinal autonomic ganglion dysfunction, leading to megacolon; and MEN4, which is also referred to as MENX, is characterized by the occurrence of parathyroid and anterior pituitary tumors in possible association with tumors of the adrenals, kidneys, and reproductive organs. This review will focus on the clinical and molecular details of the MEN1 and MEN4 syndromes. The gene causing MEN1 is located on chromosome 11q13, and encodes a 610 amino-acid protein, menin, which has functions in cell division, genome stability, and transcription regulation. Menin, which acts as scaffold protein, may increase or decrease gene expression by epigenetic regulation of gene expression via histone methylation. Thus, menin by forming a subunit of the mixed lineage leukemia (MLL) complexes that trimethylate histone H3 at lysine 4 (H3K4), facilitates activation of transcriptional activity in target genes such as cyclin-dependent kinase (CDK) inhibitors; and by interacting with the suppressor of variegation 3–9 homolog family protein (SUV39H1) to mediate H3K methylation, thereby silencing transcriptional activity of target genes. MEN1-associated tumors harbor germline and somatic mutations, consistent with Knudson’s two-hit hypothesis. Genetic diagnosis to identify individuals with germline MEN1 mutations has facilitated appropriate targeting of clinical, biochemical and radiological screening for this high risk group of patients for whom earlier implementation of treatments can then be considered. MEN4 is caused by heterozygous mutations of CDNK1B which encodes the 196 amino-acid CDK1 p27Kip1, which is activated by H3K4 methylation.
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multiple endocrine neoplasia type 1 MEN1 analysis of 1336 mutations reported in the first decade following identification of the gene
Human Mutation, 2008Co-Authors: Manuel C Lemos, Rajesh V ThakkerAbstract:Multiple endocrine neoplasia type 1 (MEN1) is an autosomal dominant disorder characterized by the occurrence of tumors of the parathyroids, pancreas, and anterior pituitary. The MEN1 gene, which was identified in 1997, consists of 10 exons that encode a 610–amino acid protein referred to as menin. Menin is predominantly a nuclear protein that has roles in transcriptional regulation, genome stability, cell division, and proliferation. Germline mutations usually result in MEN1 or occasionally in an allelic variant referred to as familial isolated hyperparathyroidism (FIHP). MEN1 tumors frequently have loss of heterozygosity (LOH) of the MEN1 locus, which is consistent with a tumor suppressor role of MEN1. Furthermore, somatic abnormalities of MEN1 have been reported in MEN1 and non-MEN1 endocrine tumors. The clinical aspects and molecular genetics of MEN1 are reviewed together with the reported 1,336 mutations. The majority (>70%) of these mutations are predicted to lead to truncated forms of menin. The mutations are scattered throughout the>9-kb genomic sequence of the MEN1 gene. Four, which consist of c.249_252delGTCT (deletion at codons 83–84), c.1546_1547insC (insertion at codon 516), c.1378C>T (Arg460Ter), and c.628_631delACAG (deletion at codons 210–211) have been reported to occur frequently in 4.5%, 2.7%, 2.6%, and 2.5% of families, respectively. However, a comparison of the clinical features in patients and their families with the same mutations reveals an absence of phenotype–genotype correlations. The majority of MEN1 mutations are likely to disrupt the interactions of menin with other proteins and thereby alter critical events in cell cycle regulation and proliferation. Hum Mutat 29(1), 22–32, 2008. © 2007 Wiley-Liss, Inc.
S Kosugi - One of the best experts on this subject based on the ideXlab platform.
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clinical features of multiple endocrine neoplasia type 1 MEN1 phenocopy without germline MEN1 gene mutations analysis of 20 japanese sporadic cases with MEN1
Clinical Endocrinology, 2000Co-Authors: N Hai, Norihiko Aoki, Akira Shimatsu, Toru Mori, S KosugiAbstract:Summary OBJECTIVE Multiple endocrine neoplasia type 1 (MEN1) is a familial tumour syndrome of endocrine tumours involving parathyroids, anterior pituitary and enteropancreatic neuroendocrine tissues, and is inherited in an autosomal dominant manner with high penetrance. Recently, the gene responsible for this syndrome, MEN1, was positionally cloned from chromosome 11q13. PATIENTS To characterize sporadic MEN1 patients, we analysed the MEN1 gene by direct sequencing of the entire open reading frame from 20 individuals. RESULTS We identified heterozygous germline mutations of the MEN1 gene in 8 of 20 (40%) cases. Seven were novel MEN1 germline mutations. Three mutations were splicing abnormalities, and all were confirmed to be splicing defects by RT-PCR. The clinical significance of detecting germline MEN1 mutations, not only in familial MEN1 but also in sporadic MEN1, was confirmed by the finding of asymptomatic mutant carriers among family members of the sporadic MEN1 patients. Seven of 8 cases with MEN1 mutations had enteropancreatic lesions in contrast to 4 of 12 (P<0.018) in those cases with no mutation. Ten of the 12 cases without MEN1 mutation were more than 50–year-old. Six of these 10 cases had the same clinical features; primary hyperparathyroidism and a GH-secreting pituitary tumour. CONCLUSIONS It Is likely that the six cases without mutations were MEN1 phenocopies due to (i) two kinds of tumours with high natural incidence in older subjects developed by chance (ii) another familial tumour syndrome with low penetrance, e.g. familial acromegaly with primary hyperparathyroidism by mutation of another gene, or (iil) somatic mutation during early embryonic stages.
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Gene diagnosis and clinical management of multiple endocrine neoplasia type 1 (MEN1).
Biomedicine & pharmacotherapy = Biomedecine & pharmacotherapie, 2000Co-Authors: N Hai, S KosugiAbstract:Identification of the MEN1 gene as a disease gene for multiple endocrine neoplasia type 1 (MEN1) has made it possible to predict whether a family member of an MEN1 patient will suffer from the same disease. MEN1 mutations have been found in almost all cases with familial MEN 1, but in fewer cases with sporadic MEN1. We analyzed MEN1 mutations in the largest number of Japanese MEN1 patients, 17 families and 21 sporadic cases, and found 54 MEN1 mutant carriers and 30 non-carriers. Furthermore, we identified a MEN1 phenocopy: GH-secreting pituitary tumor and primary hyperparathyroidism, which develops at older ages. In this article, we discuss how to utilize MEN1 gene diagnostics for the clinical management of MEN 1 patients and MEN1 mutation carriers.
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Clinical features of multiple endocrine neoplasia type 1 (MEN1) phenocopy without germline MEN1 gene mutations : analysis of 20 Japanese sporadic cases with MEN1
Clinical endocrinology, 2000Co-Authors: N Hai, Norihiko Aoki, Akira Shimatsu, Toru Mori, S KosugiAbstract:Summary OBJECTIVE Multiple endocrine neoplasia type 1 (MEN1) is a familial tumour syndrome of endocrine tumours involving parathyroids, anterior pituitary and enteropancreatic neuroendocrine tissues, and is inherited in an autosomal dominant manner with high penetrance. Recently, the gene responsible for this syndrome, MEN1, was positionally cloned from chromosome 11q13. PATIENTS To characterize sporadic MEN1 patients, we analysed the MEN1 gene by direct sequencing of the entire open reading frame from 20 individuals. RESULTS We identified heterozygous germline mutations of the MEN1 gene in 8 of 20 (40%) cases. Seven were novel MEN1 germline mutations. Three mutations were splicing abnormalities, and all were confirmed to be splicing defects by RT-PCR. The clinical significance of detecting germline MEN1 mutations, not only in familial MEN1 but also in sporadic MEN1, was confirmed by the finding of asymptomatic mutant carriers among family members of the sporadic MEN1 patients. Seven of 8 cases with MEN1 mutations had enteropancreatic lesions in contrast to 4 of 12 (P
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Germline MEN1 mutations in sixteen Japanese families with multiple endocrine neoplasia type 1 (MEN1)
European journal of endocrinology, 1999Co-Authors: N Hai, Norihiko Aoki, Toru Mori, A Matsuda, S KosugiAbstract:Objective: Multiple endocrine neoplasia type 1 (MEN1) is a syndrome of endocrine tumors involving the parathyroids, anterior pituitary and enteropancreatic neuroendocrine tissues, and is inherited in an autosomal dominant manner. Recently, the gene responsible for this syndrome, MEN1, was positionally cloned in 11q13. We aimed to assess the significance of MEN1 gene diagnostics in families with MEN1. Design: Sixteen probands of familial MEN1 and their 40 family members were subjected to the study. Methods: Full-length sequencing of the open reading frame and exon‐intron boundaries in the MEN1 gene was performed with probands of familial MEN1. Family members were examined for the identified mutation in the proband. Results: We identified heterozygous germline mutations of the MEN1 gene in all of 16 Japanese MEN1 families examined, achieving the highest detectability of MEN1 mutations in familial MEN1 among studies that examined more than 10 families. Eleven kinds of the identified MEN1 germline mutations were novel. More than half were nonsense or frameshift mutations resulting in a premature stop codon (9/15; 60%), and no mutation hot spots or no apparent genotype‐phenotype relationships were observed, in support of the results of other studies. We identified 40 mutant MEN1 gene carriers and 16 non-carriers in the course of the present study in those families. Conclusions: Analysis of the germline mutations in the MEN1 gene, providing significantly useful clinical information to probands and family members of MEN1, should be considered as a standard procedure and categorized as belonging to Group 1 cancer predisposition testing by the American Society of Clinical Oncology.