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MAX and TMEM127 mutation: which tumours and how much risk | CION Cancer Clinics
A fault in MAX or TMEM127 mainly raises the chance of a phaeochromocytoma, an adrenal tumour that makes stress hormones. Most never spread, but the hormones can push blood pressure dangerously high. This page sets out which tumours are linked to each gene, how the two genes differ, why exact figures are hard to give, and what the page cannot tell you. At CION Cancer Clinics, our oncologists explain what a gene result means for you and your family, and plan the checks that follow.
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Medically reviewed by Dr. Naresh GunduConsultant Medical Oncologist · MBBS, DNB (Internal Medicine), DM (Medical Oncology, AIIMS) · last reviewed September 2026, next review due September 2027
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On this page
- Which tumours does a MAX or TMEM127 fault cause?
- How strong is the link for each tumour?
- How would a tumour show itself in a carrier?
- What do the risk words on a MAX or TMEM127 report mean?
- How does the risk differ between MAX and TMEM127?
- What do families believe about these genes that is not true?
- What can this page not tell you?
- Common questions about MAX, TMEM127 and tumour risk
The short answer
Which tumours does a MAX or TMEM127 fault cause?
The main tumour linked to both genes is a phaeochromocytoma, a growth in the adrenal gland that makes stress hormones. Less often, the same kind of tumour grows outside the adrenal gland, where it is called a paraganglioma. Most of these tumours never spread, but they still need finding, because the hormones they release can be dangerous.
Why a tumour that is rarely cancer still matters
These tumours release adrenaline and noradrenaline in bursts. That can push blood pressure very high, strain the heart and cause a stroke. A small share can also spread to other parts of the body. For that reason doctors now treat every one of these tumours as having some ability to spread, even though most never do.
Why nobody can give you an exact figure
Both genes were linked to these tumours only in the last couple of decades, and few families have been studied. Most of those families were found because someone already had a tumour, which tends to make the risk look higher than it really is. Honest answers here are ranges and tendencies, not firm numbers.
How the two genes differ
MAX faults tend to cause tumours earlier in adult life, often in both adrenal glands. TMEM127 faults tend to cause a single tumour later in life, and many carriers never develop one at all.
A fault in either gene raises risk. It is not a diagnosis of cancer.Tumour by tumour
How strong is the link for each tumour?
One link is well established. The others rest on small numbers of families and are decided case by case.
Phaeochromocytoma
The established link for both genes. With MAX, tumours often affect both adrenal glands, sometimes years apart. With TMEM127, one gland is usually affected, and the tumour is often found in middle age.
Often shows as
- Bouts of pounding headache and sweating
- A racing heart for no clear reason
- High blood pressure that is hard to control
Paraganglioma
The same kind of tumour, growing along nerve tissue in the belly, chest or neck. It is much less common with these two genes than with the SDH genes, but it has been reported with both.
A tumour that spreads
Only a small share of these tumours spread. In the families studied so far, spread has been reported more often with MAX than with TMEM127, but the numbers are small. Long follow-up after surgery is advised for both.
Other tumours reported
A few MAX carriers have had pituitary tumours. A few TMEM127 carriers have had kidney cancer. These links are not firm, so extra checks for them are added only if your family history points that way.
Tell your counsellor about every tumour in the family, even one that seems unrelated.Not sure whether this applies to you?
Ask an oncologistFrom silent to found
How would a tumour show itself in a carrier?
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At first there is nothing to feel
A small tumour can sit in the adrenal gland for years without causing a single symptom. This is why a carrier who feels well is still offered checks.
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Hormone levels start to rise
The tumour begins to release more stress hormone than normal. A blood or urine test for metanephrines can pick this up before any symptom appears.
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Spells or high blood pressure
Some people notice sudden bouts of headache, sweating, a racing heart, paleness or a feeling of panic. Others simply have blood pressure that stays high despite medicines.
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A scan shows the tumour
A CT or MRI of the belly shows where the tumour is and how big. Some tumours are first seen by chance on a scan done for something else.
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Treatment, then follow-up
Surgery removes the tumour after the blood pressure is brought under control with tablets. Checks then continue, because a carrier can grow a new tumour on the other side.
On your report
What do the risk words on a MAX or TMEM127 report mean?
- Phaeochromocytoma
- A tumour of the inner part of the adrenal gland, which sits on top of the kidney. It makes stress hormones.
- Paraganglioma
- The same kind of tumour growing outside the adrenal gland, in the belly, chest or neck.
- Bilateral
- Affecting both sides of the body. With MAX, tumours in both adrenal glands are common.
- Metastatic
- A tumour that has spread from where it started to another part of the body, such as bone, liver or lymph nodes.
- Penetrance
- How often a fault actually leads to a tumour across everyone who carries it. For TMEM127 it appears to be low.
- Catecholamines
- The family of stress hormones, including adrenaline and noradrenaline, that these tumours make.
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Side by side
How does the risk differ between MAX and TMEM127?
MAX
TMEM127
Tumours often in both adrenal glands
Usually one adrenal gland
Often found in early adult life
Often found in middle age
Spread reported more often, though still uncommon
Spread is rarely reported
A few pituitary tumours reported
A few kidney cancers reported
Commonly believed
What do families believe about these genes that is not true?
"It is not cancer, so there is nothing to worry about."
Most of these tumours never spread, but the hormones they make can cause a dangerous rise in blood pressure. Finding one early matters for that reason alone.
"TMEM127 is mild, so carriers need no checks."
Many TMEM127 carriers never develop a tumour, but some do. Checks are usually lighter than for higher-risk genes, not absent. Your endocrinologist sets the plan.
"The tumour was removed, so the risk is over."
The fault is in every cell. A carrier can grow a new tumour in the other adrenal gland years later, which is why follow-up continues after surgery.
"Only people with high blood pressure need to worry."
Some tumours make little hormone and cause no symptoms at all until they are large. A normal blood pressure reading does not rule a tumour out.
Being straight with you
What can this page not tell you?
It cannot give you a personal risk figure. The studies behind both genes are small, and the exact change you carry, your age and your family history all shape the answer. What your specific variant means is a question for the counsellor who ordered the test.
It cannot read a tumour report
This page covers inherited faults, present in every cell from birth. A test run on a tumour to choose treatment answers a different question. It is covered on our targeted therapy pages.
Who this does not apply to
Relatives who have tested negative for the family's exact fault do not carry this risk and need no special checks. Most people with high blood pressure do not have one of these tumours, and do not need genetic testing. Your doctor will say if your pattern of symptoms is worth looking into.
Questions we are asked
Common questions about MAX, TMEM127 and tumour risk
Is a phaeochromocytoma a cancer?
Most do not spread and are removed by surgery without further treatment. A small share do spread, and there is no reliable way to tell in advance which ones will. That is why doctors treat every one with care, and why follow-up continues for years after the operation.
Which is more serious, a MAX or a TMEM127 fault?
In the families studied so far, MAX has tended to cause tumours earlier, more often in both glands, and with spread reported a little more often. TMEM127 tends to be milder. Both are based on small studies, so your own plan depends on your family, not on the gene name alone.
Can a child get one of these tumours?
It is uncommon, particularly with TMEM127. MAX tumours can appear in young adults and, rarely, earlier. When to begin checks for a child who carries the fault is decided with your counsellor and endocrinologist, based on the gene and on the ages seen in your family.
Does it matter which parent passed the MAX fault on?
Early reports suggested MAX tumours appear mainly when the fault came from the father. The studies are small and the pattern is not firm. For now, relatives on both sides are offered testing and checks in the same way.
What symptoms should a carrier never ignore?
A sudden severe headache with a pounding heart, heavy sweating, chest pain or a feeling of panic. These can mean a burst of hormone from a tumour. Go to the nearest emergency department the same day and tell the doctor you carry a MAX or TMEM127 fault.
Is it safe to have an operation or get pregnant as a carrier?
Usually yes, with one precaution. An undetected tumour can cause a dangerous spike in blood pressure during surgery, childbirth or some scans. Tell every doctor about your result first, so a hormone test can be done beforehand.
My report says variant of uncertain significance. What now?
An uncertain result is not a positive result. The laboratory found a change but does not yet know whether it matters. It should not lead to checks for relatives or to surgery. Ask how you will be told if it is ever reclassified.
Should everyone with a phaeochromocytoma be tested?
Many specialists now offer genetic testing to everyone with one of these tumours, because they are among the tumours most often inherited. MAX and TMEM127 are usually tested on the same panel as RET, VHL, NF1 and the SDH genes.
Your Specialists
Meet CION's oncologists. Bring your family history or genetic report to them.
Our medical oncologists see people with a strong family history of cancer, arrange genetic counselling and testing where it fits, and plan the checks that follow.
Medical Oncologist
Dr. C. Raghavendra Reddy
MBBS(Gold Medal), DNB(General Medicine), DM(Medical Oncology)(Gold Medal)
Medical Oncologist
Dr. Bharati Devi Gorantla
MBBS, MD(General Medicine), DM(Medical Oncology)(Adyar,Chennai), ECMO, MRCP SCE(UK)
Medical Oncologist
Dr. Owais Mohammed
MBBS, MD (General Medicine), DrNB (Medical Oncology), ECMO, MRCP SCE (Medical Oncology) (UK)
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Sources
- GeneReviews (NCBI) — Hereditary Paraganglioma-Pheochromocytoma Syndromes
- MedlinePlus Genetics — Hereditary paraganglioma-pheochromocytoma
- MedlinePlus Genetics — MAX gene
- MedlinePlus Genetics — TMEM127 gene
This page is general information, not a prescription. Do not change or stop any treatment based on what you read here. If anything is worrying you, contact your own treating team — or call our helpline and we will help you reach the right specialist.
Keep reading
Related pages
MAX and TMEM127: what the genes doHow these brake genes work, before the risksMAX and TMEM127 positive: what happens nextThe first tests and scans after a positive resultTesting the family for MAX and TMEM127Which relatives to test, and in what orderWhy every paraganglioma case is testedWhy testing is offered to everyone with this tumour
Talk to us
Want your MAX or TMEM127 result explained?
Bring the report and any earlier scans or hormone tests. A counsellor will explain what the result means for you and your relatives, in Telugu if you prefer. One helpline serves every CION centre.