# Multiple endocrine neoplasia type 1 (MEN1)

Source: https://onco.cc/cancers/men1-syndrome/  
OnCo record `men1-syndrome` (Cancer). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

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.

How 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).

Treatment 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.

## Fields

- Kind: Cancer
- Last checked: 2026-09-24
- Also known as: MEN1; Wermer syndrome; MEN1 (menin; parathyroid, pancreatic NET, pituitary)
- Tags: subtype-page; wave4; rare
- 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

## Sections of this record

The page is a hub with ten sections in reading order; large sections have their own page. The same plan as JSON: https://onco.cc/api/v1/cancers/men1-syndrome/sections.json

- Overview (on the hub): The TL;DR, the family this cancer belongs to, the organ, who gets it and what the state of the art is. https://onco.cc/cancers/men1-syndrome/#overview
- What it is (on the hub): Anatomy, the subtypes and how they differ, how it is staged, and where advanced disease spreads. https://onco.cc/cancers/men1-syndrome/#what-it-is [4 subtypes]
- Finding it (on the hub): How it shows itself, how it is confirmed, what screening exists, and the biomarkers clinicians test for. https://onco.cc/cancers/men1-syndrome/#finding-it [5 biomarkers]
- Treating it (on the hub): The standard of care by setting, the medicines, surgery and radiotherapy named in it, and the regimens behind them. https://onco.cc/cancers/men1-syndrome/#treating-it [1 setting]
- Evidence (on the hub): Trials recruiting now, the landmark trials, the key papers and what they mean, the latest literature, and the milestones year by year. https://onco.cc/cancers/men1-syndrome/#evidence [1 key paper]
- The science (on the hub): The molecular landscape: the targets and how often each appears, the pathways, the mechanics stages and the preclinical models. https://onco.cc/cancers/men1-syndrome/#science [1 target]
- Where you are (own page): Cases by country, the UK and NHS pathway and other country lenses, and the expert centres with trials on record. https://onco.cc/cancers/men1-syndrome/where-you-are/
- Living with it (on the hub): The decisions you may face, the aids that walk through them, the warnings on record, the first sixty days and the questions to ask. https://onco.cc/cancers/men1-syndrome/#living-with-it [7 questions]
- What is coming (own page): Everything in development, the open problems and what is being done about them, the roadmaps, and what changed on this record. https://onco.cc/cancers/men1-syndrome/coming/
- Data (own page): Every connected record, the notes, the JSON, Markdown and RDF twins, and where the record came from and when it was checked. https://onco.cc/cancers/men1-syndrome/data/ [5 connected records]

## Standard of care

- All manifestations: Treated by manifestation as the parent page describes, with germline testing of relatives and lifelong multidisciplinary surveillance. ([Multiple endocrine neoplasia syndromes (MEN1, MEN2, MEN4)](https://onco.cc/cancers/multiple-endocrine-neoplasia/), [Germline (hereditary) testing](https://onco.cc/technologies/germline-testing/), [MEN1 and hereditary neuroendocrine syndromes](https://onco.cc/terms/men1-hereditary-net/))

## Sources

- Wikipedia: https://en.wikipedia.org/wiki/Multiple_endocrine_neoplasia_type_1
- NCI: multiple endocrine neoplasia (MEN) syndromes: https://www.cancer.gov/types/multiple-endocrine-neoplasia
- Thakker 2012, JCEM: clinical practice guidelines for MEN1: https://doi.org/10.1210/jc.2012-1230
- Orphanet: multiple endocrine neoplasia type 1 (ORPHA:652): https://www.orpha.net/en/disease/detail/652
- Ye 2017, Clin Endocrinol: thymic neuroendocrine tumours in MEN1, meta-analysis: https://doi.org/10.1111/cen.13480
- Singh Ospina 2016, Clin Endocrinol: parathyroid carcinoma in 348 patients with MEN1: https://doi.org/10.1111/cen.12714

## Connected records

- cancers: [Glucagonoma](https://onco.cc/cancers/glucagonoma/), [Hyperparathyroidism-jaw tumour syndrome (CDC73-related parathyroid carcinoma)](https://onco.cc/cancers/hyperparathyroidism-jaw-tumour-syndrome/), [Lactotroph pituitary neuroendocrine tumour (prolactinoma)](https://onco.cc/cancers/lactotroph-pitnet/), [Lung neuroendocrine tumours (typical and atypical carcinoid)](https://onco.cc/cancers/lung-net/), [Multiple endocrine neoplasia syndromes (MEN1, MEN2, MEN4)](https://onco.cc/cancers/multiple-endocrine-neoplasia/), [Multiple endocrine neoplasia type 2 (MEN2A and MEN2B)](https://onco.cc/cancers/men2-syndrome/), [Pancreatic neuroendocrine tumours](https://onco.cc/cancers/pancreatic-net/), [Parathyroid carcinoma](https://onco.cc/cancers/parathyroid-carcinoma/), [Pituitary tumours (pituitary neuroendocrine tumours) and pituitary carcinoma](https://onco.cc/cancers/pituitary-tumours/), [Somatostatinoma](https://onco.cc/cancers/somatostatinoma/), [VIPoma](https://onco.cc/cancers/vipoma/)
- technologies: [Germline (hereditary) testing](https://onco.cc/technologies/germline-testing/)
- targets: [Menin](https://onco.cc/targets/menin/)
- terms: [Hereditary cancer syndromes](https://onco.cc/terms/hereditary-cancer-syndromes/), [MEN1 and hereditary neuroendocrine syndromes](https://onco.cc/terms/men1-hereditary-net/)
- key papers: [Clinical practice guidelines for multiple endocrine neoplasia type 1 (MEN1)](https://onco.cc/key-papers/paper-thakker-j-clin-endocrinol-metab/)

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JSON: https://onco.cc/api/v1/entities/men1-syndrome.json