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Endocrine and Neuroendocrine Tumors
Published in Pat Price, Karol Sikora, Treatment of Cancer, 2020
Natasha Shrikrishnapalasuriyar, P.N. Plowman, Márta Korbonits, Ashley B. Grossman
The prevalence of MEN1 detected from post-mortem studies is estimated to be 0.25%, although in general the population prevalence is in the region of 1:40,000. It is seen in up to 18% of young patients with primary hyperparathyroidism, 16–38% in patients with gastrinomas, but less than 3% in patients with pituitary tumors.43 The observation of loss of heterozygosity (LOH) of chromosome 11q13 in tumors from MEN1 patients led to the mapping, in 1988 and later cloning, in 1997, of the MEN1 gene. This gene spans 7.2 kb of genomic sequence, contains an 1,830-bp coding region with 10 exons (the first is not translated) and encodes a 610 amino-acid protein, menin.44MEN1 mutations are detected in 90–95% of MEN1 patients. MEN1 is considered a tumor suppressor gene because heterozygous inactivating mutations predispose to neoplasia and the majority of MEN1-related tumors show LOH at 11q13.45–47 MEN1 has an autosomal dominant pattern of inheritance but can occur sporadically as a new mutation. Penetrance is variable and age- and organ-specific, but the hyperparathyroidism usually presents by the fifth decade.48 It should be emphasized that there is little genotype–phenotype correlation in MEN1.
Pediatric Central Nervous System Tumors as Phenotypic Manifestation of Cancer Predisposition Syndromes
Published in David A. Walker, Giorgio Perilongo, Roger E. Taylor, Ian F. Pollack, Brain and Spinal Tumors of Childhood, 2020
Giorgio Perilongo, Irene Toldo, Stefano Sartori
Prolactin-producing pituitary adenoma, which occurs very rarely in children, may herald the presence of multiple endocrine neoplasia type 1 (MEN1: Wermer syndrome). MEN1 is an autosomal inherited condition predisposing to tumors of the pancreas, pituitary, and parathyroid glands as well as carcinoid tumors and gastrinoma. The disease is linked to a germline mutation in the tumor suppressor gene MEN1 located on the long arm of chromosome 11, encoding a protein called menin.73
Neuroendocrine tumours
Published in Anju Sahdev, Sarah J. Vinnicombe, Husband & Reznek's Imaging in Oncology, 2020
Sairah R Khan, Kathryn L Wallitt, Adil Al-Nahhas, Tara D Barwick
Whilst most PNETs are sporadic, NETs are associated with several genetic syndromes including MEN1, VHL disease, NF1, and tuberous sclerosis. NETs occur in 80%–100% of patients with MEN1 (Figure 24.9), up to 20% of patients with VHL disease (Figure 24.10), 10% of patients with NF1, and in 1% of patients with tuberous sclerosis. MEN1 is a rare autosomal dominant syndrome which affects the parathyroid glands (95%), the pancreas (40%–70%) (Figure 24.9), and the pituitary gland (30%–40%) and less commonly causes tumours in the lungs, thymus, and adrenal cortex (68). Although not the most common manifestation of MEN1, pancreatic, bronchial, and thymic NETs have high malignant potential, and metastases from these are a common cause of death in MEN1 patients (78). One-third of sporadic cases of gastrinoma have been shown to have similar chromosomal mutations to patients with MEN1.
Cutting edge approaches to detecting brain mosaicism associated with common focal epilepsies: implications for diagnosis and potential therapies
Published in Expert Review of Neurotherapeutics, 2021
Zimeng Ye, Mark F. Bennett, Melanie Bahlo, Ingrid E. Scheffer, Samuel F. Berkovic, Piero Perucca, Michael S. Hildebrand
Genetic analysis of the paired PNH- and blood-derived DNA samples failed to detect any variants in known familial or sporadic PNH genes but did reveal a mosaic MEN1 duplication (c.1546dupC) variant predicted to lead to frameshift (p.R615PfsX15) in 16.7% of sequenced reads in PNH DNA. The presence of this variant in PNH DNA, and its absence from blood, was confirmed independently by Sanger sequencing. This variant had been reported at high frequency as a germline heterozygous change in patients with multiple endocrine neoplasia type 1 (MEN1) syndrome with in vitro functional studies confirming that it impairs nuclear localization [62]. Germline mutations in MEN1 are well known to cause MEN1 syndrome and double-hit mutations (a constitutional germline mutation with a second somatic mutation) in MEN1 can cause MEN1 syndrome-related tumors such as ependymoma, lipoma, and parathyroid tumor [63,64]. However, this gene is not related to PNH. It is possible that constitutional mutation or double-hit mutations in MEN1 can cause MEN1 syndrome, while mosaicism may lead to other phenotypes (e.g. PNH) through mechanisms like cellular interference between cell populations with and without mutations, already established for some X-linked disorders [65–67].
An unusual presentation of insulinoma and the serious consequences of delayed diagnosis
Published in Journal of Endocrinology, Metabolism and Diabetes of South Africa, 2020
Insulinomas are rare functioning neuroendocrine tumours. They occur in 1–4 per million per year.2 They are the most common class of neuroendocrine tumours. They occur more commonly in females, with an average age at presentation of 50 years.3 Insulinomas are commonly sporadic in nature. Less than 10% are genetic in origin, associated with multiple endocrine neoplasia type 1 (MEN-1).3 MEN-1 is an autosomal-dominant syndrome affecting mainly the parathyroid glands, anterior pituitary, endocrine pancreas and duodenum, due to inactivation of the MEN1 gene on chromosome 11q13. Of the patients with insulinoma associated with MEN1, the presentation is earlier and female predominant 2. The majority of patients with insulinomas present with hypoglycaemia in the fasting state although it can also occur in the post-prandial state.3
Surgical management of pancreatic neuroendocrine tumors: an introduction
Published in Expert Review of Anticancer Therapy, 2019
Elisabeth Hain, Rémy Sindayigaya, Jade Fawaz, Joseph Gharios, Gaspard Bouteloup, Philippe Soyer, Jérôme Bertherat, Frédéric Prat, Benoit Terris, Romain Coriat, Sébastien Gaujoux
MEN1 is a rare disease with an estimated prevalence of 1 to 10/100,000 inhabitants. Suspected MEN1 should be observed in patients who are diagnosed with a typical MEN1 manifestation at a young age (<30 years), those with multiple duodenopancreatic-NETs, or duodenopancreatic-NETs associated with hypercalcemia or another endocrinopathy at any age. Duodenopancreatic-NETs occur in more than 75% (in some series, up to more than 90%) of patients with MEN1 and are invariably multifocal. Duodenopancreatic-NETs are associated with an earlier age of onset in MEN1 than in sporadic cases. In order to reduce the morbidity and mortality associated with DP-NENs, biochemical and radiological screening is indicated to start from 16 years of age. Biochemical dosage and imaging for the diagnosis of the NEN related to MEN 1 remains the same as previously described.