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Facts for people and families with Multiple Endocrine Neoplasia type 1

This fact sheet contains general information about Multiple Endocrine Neoplasia type 1 (MEN type 1). Each person should be referred to a genetic service for further information and advice. 

Key Points

  • MEN type 1 is due to faults (mutations) in the MEN1 gene.
  • People with MEN type 1 have an increased chance of developing tumours in their endocrine glands. These tumours are usually benign (non-cancerous), but sometimes they are malignant (cancerous).
  • Family members (including children) can be referred to a genetic service where experts can provide information, advice and support about their chance of developing cancer and the option of genetic testing.
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The MEN1 gene is a ‘tumour protection’ gene that helps to protect against tumours developing in the body, particularly within the endocrine glands which are involved in making hormones. If a tumour develops in an endocrine gland, extra hormones may be released into the blood causing many different symptoms throughout the body.

Everyone has two MEN1 genes (one from their mother, and one from their father). If one of the genes is not working, this is known as having a faulty MEN1 gene, or having a MEN1 mutation. People with a faulty MEN1 gene are known to have Multiple Endocrine Neoplasia type 1.

Cancer

People with MEN type 1 have:

  • about a 90% chance of developing a neuroendocrine tumour (NET) of the stomach, duodenum or pancreas (called a gastroduodenopancreatic NET or GDP-NET) over their lifetime. These tumours may be malignant.
  • about a 20% chance of developing a NET of the lungs (called a bronchopulmonary NET) over their lifetime. They also have a small chance (about 2%) of developing a NET of the thymus gland (called a thymic NET). These tumours may be malignant. 

Benign tumours

People with MEN type 1 have:

  • a 90–95% chance of developing tumours in the parathyroid glands (called parathyroid adenoma or hyperplasia) over their lifetime. These tumours cause hyperparathyroidism (high parathyroid hormone [PTH] and calcium levels in the blood).
  • a 30–40% chance of developing a tumour in the pituitary gland (called pituitary adenoma) over their lifetime.
  • a 25–40% chance of developing a tumour in the adrenal gland (called adrenocortical tumour) over their lifetime.
  • about an 8% chance of developing a tumour in the membranes around the brain and spinal cord (called a meningioma) over their lifetime.
  • Not everyone with MEN type 1 will develop a tumour and/or cancer.
  • To find tumours and cancer early, people with MEN type 1 should have a blood test to check their hormone levels and a physical examination with a doctor every year from age 10 years. 
  • To find tumours and cancer early, people with MEN type 1 should have imaging to check their brain at age 10 years. This imaging should then be done every four years from age 20 years. Imaging to check the pancreas, duodenum, chest and adrenal glands should be done every 2 years from age 20 years. This involves having MRI scans.

Family members (including children) of someone with a faulty MEN1 gene can have genetic testing to check who has the faulty gene and who does not. Their doctor can refer them to a genetic service to find out more about their chance of developing cancer and what genetic testing involves.

If a person does have the faulty MEN1 gene:

  • they can pass it onto their children
  • each child has a 50% (1 in 2) chance of being born with it. Pregnancy planning options are available to people who want to prevent the faulty gene from being passed on.

If a person does not have the faulty MEN1 gene: 

  • they have the same chance of developing tumours and/or cancer as the general population (unless there are other factors that increase this risk)
  • they cannot pass it on to their children.
People who decide not to have genetic testing should still get advice about managing their chance of developing cancer.

Version 3

Date Summary of changes
17/05/2022

Consumer information sheet reviewed in line with risk management protocol (ID 192). Approved for publication with the following changes made: 

What is the risk of cancer and tumours for people with MEN type 1?

  • Cancer:
    • 'about a 30-70% chance of developing a neuroendocrine tumour of the stomach, duodenum or pancreas...' changed to 'About a 90% chance...'
    • Added 'about a 20% chance of developing a NET of the lungs (called a bronchopulmonary NET) over their lifetime. They also have a small chance (about 2%) of developing a NET of the thymus gland (called a thymic NET). These tumours may be malignant.'
  • Benign tumours:
    • 'about a 40% chance of developing a tumour in the pituitary gland...' changed to 'a 30-40% chance...'

Version updated to V.3. To be reviewed alongside ID 192 when next due for review.

Version 2

Date Summary of changes
04/06/2019

Reviewed in parallel with associated GT and RM protocols. Approved for publication with the following changes made:

  • All abbreviations of multiple endocrine neoplasia type 1 changed from 'MEN1' to 'MEN type 1'
  • All mentions of 'gastroenteropancreatic NET' and 'GEP-NET' changed to 'gastroduodenopancreatic NET' and 'GDP-NET'.

Key points section: 

  • 'occasionally' changed to 'sometimes' in second bullet point.

What is a faulty MEN1 gene? section:

  • Description updated with minor changes.

What is the risk of cancer and tumours for people with MEN type 1? section:

  • Risk of NET updated from 'about a 30-80%' to 'a 30-70%', 'bowel' changed to 'duodenum'. Slight update to wording of sentence regarding NETs in other areas of the body.
  • 'About a 90-95%' changed to 'a 90-95%' chance of parathyroid adenomas.
  • Risk of pituitary adenomas updated from '30-40%' to '40%'.
  • Risk of adrenocortical tumours updated from 40% to 25-40%
  • Risk of meningiomas updated from '5-8%' to '8%'.

How can this increased risk of tumours and cancer be managed? section:

  • Recommendation on brain imaging updated to align with RM protocol (ID 192).

Version changed to V.2. To be reviewed again alongside protocol ID 192 when next due for review.

Version 1

Date Summary of changes
27/04/2018 Developed in conjunction with consumer information sheet working group and presented at the November 2017 cancer genetics reference committee meeting. Discussions continued over email and document approved for publication. V.1. 

This cancer genetics fact sheet is a guide only and cannot cover every possible situation. The information provided is not intended to replace discussion with a health professional, and should not be interpreted as medical advice. While eviQ endeavours to link to reliable sources that provide accurate information, eviQ and the Cancer Institute NSW do not endorse or accept responsibility for the accuracy, currency, reliability or correctness of the content of linked external information sources. Use of this document is subject to eviQ's disclaimer available at www.eviQ.org.au/copyright  

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https://www.eviq.org.au/p/3447

19 Apr 2024