Having a family history of melanoma

Our natural risk of illness depends in part on our genes – the instructions that our bodies use to grow and repair themselves.

To decide the risk of illness such as melanoma, to family members, doctors look for signs of high-risk genes within the family.

Those signs are:

  • Several cases of melanoma within a family.
    The more cases of melanoma the more likely there will be a high-risk gene in that family. However, more than one case might occur by chance alone or because the family live somewhere with a high environmental risk (somewhere sunny like Australia). Some families may also have family members with cancer of the pancreas.
  • Three of more melanomas in a single family member.
    When a person develops multiple primary melanomas they may have a high-risk gene, but research has shown that in the absence of a family history of melanoma, most such people do not have a high risk gene such as CDKN2A: it is likely that many of these people have several low risk genes eg those associated with skin which tends to burn in the sun, and they have had quite a lot of sun exposure. In such a case, then the affected family members would be less likely to pass on a significant risk of melanoma to their children.
  • Melanoma occurring earlier than usual.
    Most cases of melanoma are in people aged 50 or older. In families with high-risk genes then melanoma occurs a little earlier on average.

Referral to a specialist

Families who are concerned that they may be at increased risk of melanoma are usually referred to specialist doctors for counselling. These doctors are often clinical geneticists or specialist dermatologists. They will take a family history and use this information to give advice about risk. If you are referred to such a service you can help by thinking about the sort of information they will want to know.


Questions to consider:

  • Who in the family has had cancer?
  • What type of cancer was it? (Occasionally other types of cancer can occur in families with high-risk melanoma genes.)
  • How old were they when they developed it?

Your family doctor or dermatologist may refer you to a clinical geneticist or specialist dermatologist if:

  • Two first-degree relatives have had melanoma. First-degree relatives are your sisters, brothers, parents or children.
  • You have one relative who has had a melanoma, and one of you has had two or more melanomas.
  • There are three or more people who have had melanoma in your family (ie first and more distant relatives).

What would the clinical geneticist or specialist dermatologist do?

1. Make a ‘family tree’ by talking to family members and reviewing medical records. This tree would show family relationships, noting the types of cancers people have had and at what age.

2. They would look for the nature of the family links between those who have had cancer. Two cases in sisters will be more relevant than two cases in distant cousins.

3. They will look for cancer at an early age and people who have had more than one cancer.

4. They will then look for patterns of type of cancer within the family eg several family members with the same sort of cancer is usually a stronger sign of a high-risk cancer gene than cases of different types of cancer.

5. Having assessed the family history, they will then estimate the chances of a gene being present within the family that could lead to melanoma, and the chances of the individual family member under investigation carrying that gene.

6. In some cases they may offer the family a gene test for two related genes called CDKN2A (or the p16 gene) or CDK4. If this test is negative, then patients may be offered additional tests for rarer susceptibility genes.

7. They would then suggest how to cope with and reduce their risk of developing a melanoma. Their advice would probably include sun protection measures and self-examination (see relevant sections in ‘Coping with a Diagnosis of Melanoma’).

Should I consider genetic testing?
Where the family history suggests that a high-risk melanoma gene may be present in a family then the clinical geneticist may offer gene testing. When testing a family member then the first person to be tested will always be a person who has had a melanoma. Often the geneticist would prefer to test someone who has had more than 1 melanoma, because if the family does have a high-risk gene then its more likely that such a person would be one to carry that high-risk gene.

What gene mutations can cause melanoma?

We know of several genes where mutations (changes or faults in our genes) can increase the chances of developing a melanoma. GenoMEL, the Melanoma Genetics Consortium, is doing further research in this area and more may be discovered in the future.

The most common gene is CDKN2A; it produces a protein called p16. Families carrying mutations in this gene have been discovered in Europe, the USA and Australia. In most ‘CDKN2A families’ in the UK, carrying the mutant gene appears only to increase the risk of melanoma. In the Netherlands, Sweden and the USA however, there also appears to be an increased risk of pancreatic cancer.

The more cases of melanoma there are in the family, the greater the likelihood that the family carries a high-risk mutation such as CDKN2A. Most of the families that we know possess a CDKN2A mutation have more than two cases of melanoma.

We have put information about genetic counselling in the section for melanoma health care teams on this web site. This is written for medically trained people but some families might find the information helpful.

The second most frequent gene (but still very rare) is a gene called CDK4 and in the UK melanoma families tested for CDKN2A mutations are usually also tested for CDK4 mutations. The GenoMEL consortium has published a paper on families with CDK4 mutations and a plain language summary is found in the plain language section of this website.

Since 2014 new mutations in even rarer genes have been found for the first time, in genes called TERT and POT1. So little is known about these genes as yet in terms of what they mean for families in terms of risk, that gene testing is not widely available as yet.

Gene Testing

What about gene testing?

There is a test for mutations in the CDKN2A gene and GenoMEL uses such a test in its research. This work is vital to understanding melanoma and finding better ways of preventing and treating it.

Testing is also available clinically (as part of individual treatment) in several countries including the USA.

Some feel that routine testing of family members might be premature. Why?

  • A negative test result might only mean a family possesses other high-risk genes for melanoma that we have yet to identify.
  • With the information we currently have it is difficult to say exactly what the chances of developing a melanoma are with a positive test in different regions of the world.
  • A positive test would not really change a person’s treatment or care. Patients should still see their specialist regularly and be advised to practice sun protection.
  • A positive test might have an impact on insurance premiums in the future.

Testing may well be helpful for some families and not for others: going to see a Clinical Geneticist is therefore about counselling to enable you to make your own mind up as to whether a test is right for you.