{"entity":{"id":"men1-syndrome","kind":"cancer","name":"Multiple endocrine neoplasia type 1 (MEN1)","aka":["MEN1","Wermer syndrome","MEN1 (menin; parathyroid, pancreatic NET, pituitary)"],"tldr":"MEN1 is an inherited condition, one of the multiple endocrine neoplasia syndromes, in which a faulty MEN1 gene lets tumours grow in the parathyroid glands, the pancreas and the pituitary. Each tumour is treated much as it would be in anyone else, but because there are many of them and they come back, families are followed for life in specialist clinics.","summary":"MEN1 is an autosomal dominant disorder caused by germline mutations in the tumour suppressor gene MEN1, which encodes the 610-amino-acid protein menin. It is defined by tumours of the parathyroid glands, the pancreatic islets and the anterior pituitary; some patients also develop carcinoid (neuroendocrine) tumours of the thymus, lung and stomach, adrenocortical tumours, meningiomas, facial angiofibromas, collagenomas and lipomas (Thakker 2012). The WHO classification of endocrine and neuroendocrine tumours (5th edition) lists MEN1 among the genetic tumour syndromes rather than as a tumour, which is why it sits here as an entity under the syndromes page.\n\nHow it differs from its parent: MEN1 is the menin-driven syndrome; MEN2 is driven by RET and centres on the thyroid. Within MEN1 the pancreatic and thymic tumours carry the mortality: patients have a decreased life expectancy, and the outcomes of treatments that work in sporadic tumours are less good because the tumours are multiple, often larger and more aggressive, and metastases coincide (Thakker 2012). Thymic neuroendocrine tumour accounts for almost a fifth of MEN1-associated deaths; its pooled prevalence in 2,710 MEN1 patients was 3.7 percent, four fifths of them men (Ye 2017). Parathyroid carcinoma is rare in MEN1: one case in 348 patients (0.28 percent) in a Mayo cohort, with ten reported in the literature (Singh Ospina 2016).\n\nTreatment is by manifestation, as the parent page sets out: parathyroid surgery for hyperparathyroidism, resection of functioning or larger pancreatic neuroendocrine tumours, medical treatment of gastrinoma, and the sporadic pathways for pituitary and neuroendocrine tumours. The guideline recommends presymptomatic detection by MEN1 mutation testing of first-degree relatives and lifelong surveillance under a multidisciplinary team with experience of endocrine tumours (Thakker 2012). Menin inhibitors approved for leukaemia act on the same protein but have no trial in MEN1.","asOf":"2026-09-24","wikipedia":"https://en.wikipedia.org/wiki/Multiple_endocrine_neoplasia_type_1","links":[{"label":"NCI: multiple endocrine neoplasia (MEN) syndromes","url":"https://www.cancer.gov/types/multiple-endocrine-neoplasia"},{"label":"Thakker 2012, JCEM: clinical practice guidelines for MEN1","url":"https://doi.org/10.1210/jc.2012-1230"},{"label":"Orphanet: multiple endocrine neoplasia type 1 (ORPHA:652)","url":"https://www.orpha.net/en/disease/detail/652"},{"label":"Ye 2017, Clin Endocrinol: thymic neuroendocrine tumours in MEN1, meta-analysis","url":"https://doi.org/10.1111/cen.13480"},{"label":"Singh Ospina 2016, Clin Endocrinol: parathyroid carcinoma in 348 patients with MEN1","url":"https://doi.org/10.1111/cen.12714"}],"tags":["subtype-page","wave4","rare"],"related":["multiple-endocrine-neoplasia","men2-syndrome","pancreatic-net","pituitary-tumours","lung-net","parathyroid-carcinoma"],"cancers":[],"sections":[],"technologies":["germline-testing"],"targets":["menin"],"drugs":[],"companies":[],"institutions":[],"pathways":[],"terms":["men1-hereditary-net","hereditary-cancer-syndromes"],"trials":[],"people":[],"bottlenecks":[],"keyPapers":["paper-thakker-j-clin-endocrinol-metab"],"journals":[],"dependsOn":[],"notes":[],"group":"endocrine","burden":"Orphanet lists MEN1 as a rare disease (ORPHA:652). The 2012 international guideline gives no incidence figure in its abstract; first-degree relatives of a carrier have a 50 percent chance of inheriting the mutation (Thakker 2012). No GLOBOCAN estimate exists for a syndrome.","subtypes":["Classic MEN1 with parathyroid, pancreatic islet and pituitary tumours","MEN1 with thymic or bronchial neuroendocrine tumour","MEN1-associated parathyroid carcinoma (rare)","Phenocopies and MEN4 (CDKN1B) presenting like MEN1"],"biomarkers":["Germline MEN1 mutation (first-degree relatives have a 50 percent risk)","Calcium and parathyroid hormone","Gastrin, insulin and glucose, chromogranin A","Prolactin and insulin-like growth factor 1","Pancreatic and thymic imaging on the guideline surveillance schedule"],"standardOfCare":[{"setting":"All manifestations","approach":"Treated by manifestation as the parent page describes, with germline testing of relatives and lifelong multidisciplinary surveillance.","refs":["multiple-endocrine-neoplasia","germline-testing","men1-hereditary-net"]}],"stateOfArt":[],"history":[],"pipeline":[],"openProblems":[],"parent":"multiple-endocrine-neoplasia"},"route":"/cancers/men1-syndrome/","neighbours":{"cancer":[{"id":"glucagonoma","kind":"cancer","name":"Glucagonoma","route":"/cancers/glucagonoma/"},{"id":"hyperparathyroidism-jaw-tumour-syndrome","kind":"cancer","name":"Hyperparathyroidism-jaw tumour syndrome (CDC73-related parathyroid carcinoma)","route":"/cancers/hyperparathyroidism-jaw-tumour-syndrome/"},{"id":"lactotroph-pitnet","kind":"cancer","name":"Lactotroph pituitary neuroendocrine tumour (prolactinoma)","route":"/cancers/lactotroph-pitnet/"},{"id":"lung-net","kind":"cancer","name":"Lung neuroendocrine tumours (typical and atypical carcinoid)","route":"/cancers/lung-net/"},{"id":"multiple-endocrine-neoplasia","kind":"cancer","name":"Multiple endocrine neoplasia syndromes (MEN1, MEN2, MEN4)","route":"/cancers/multiple-endocrine-neoplasia/"},{"id":"men2-syndrome","kind":"cancer","name":"Multiple endocrine neoplasia type 2 (MEN2A and MEN2B)","route":"/cancers/men2-syndrome/"},{"id":"pancreatic-net","kind":"cancer","name":"Pancreatic neuroendocrine tumours","route":"/cancers/pancreatic-net/"},{"id":"parathyroid-carcinoma","kind":"cancer","name":"Parathyroid carcinoma","route":"/cancers/parathyroid-carcinoma/"},{"id":"pituitary-tumours","kind":"cancer","name":"Pituitary tumours (pituitary neuroendocrine tumours) and pituitary carcinoma","route":"/cancers/pituitary-tumours/"},{"id":"somatostatinoma","kind":"cancer","name":"Somatostatinoma","route":"/cancers/somatostatinoma/"},{"id":"vipoma","kind":"cancer","name":"VIPoma","route":"/cancers/vipoma/"}],"technology":[{"id":"germline-testing","kind":"technology","name":"Germline (hereditary) testing","route":"/technologies/germline-testing/"}],"target":[{"id":"menin","kind":"target","name":"Menin","route":"/targets/menin/"}],"term":[{"id":"hereditary-cancer-syndromes","kind":"term","name":"Hereditary cancer syndromes","route":"/terms/hereditary-cancer-syndromes/"},{"id":"men1-hereditary-net","kind":"term","name":"MEN1 and hereditary neuroendocrine syndromes","route":"/terms/men1-hereditary-net/"}],"paper":[{"id":"paper-thakker-j-clin-endocrinol-metab","kind":"paper","name":"Clinical practice guidelines for multiple endocrine neoplasia type 1 (MEN1)","route":"/key-papers/paper-thakker-j-clin-endocrinol-metab/"}]}}