This was in “The Australian” this morning. It reinforces how the development of melanoma is a complex relationship between UV exposure and a person’s genetic background. Your patients may ask you about this today.
Gene sees risk of melanoma double
- BY:ADAM CRESWELL, HEALTH EDITOR , November 14, 2011 12:00AM
AUSTRALIAN researchers have identified a gene mutation carried by an estimated 200,000 Australians that more than doubles the person’s risk of developing the potentially fatal skin cancer melanoma.
The mutation, which occurs in a gene previously suspected but not proven to play a role in melanoma growth, increases a person’s lifetime risk of developing the disease from 4 per cent to about 10 per cent.
Experts hope the findings about the MITF gene, published today in the prestigious international journal Nature, will lead to other genes being identified that act together and account for one-third or more of melanoma cases.
The ultimate goal – which remains several years away – will be the development of a test that can identify which Australians are at highest melanoma risk so they can be more vigilant, and possibly treatments that can prevent the disease, or slow or halt it once it has developed.
Australia has the highest incidence rates in the world for melanoma, along with New Zealand. Melanoma accounts for more than 10,000 new cases and 1200 deaths each year, making it the fourth most common cancer in Australia, and the most common in those aged 15-44, along with breast cancer.
The new study, co-authored by 47 researchers from Australia, the US and Britain, found the MITF mutation was present in about 1 per cent of the population. It was typically found in people with eye colour other than blue, and was not associated with skin colour, hair colour or freckling – all factors that are already known to raise melanoma risk.
The extra melanoma risk the mutation confers is thought to be comparable to that faced by redheads, who generally have white-ish skin that burns easily.
One of the 31 Australian co-authors of the paper, Graham Mann, research program leader at the Westmead Millennium Institute and Melanoma Institute of Australia at the University of Sydney, said while the 10 per cent risk was a “moderate” increase, more work was expected to reveal other gene combinations that would put affected people at 30 to 40 per cent risk of the disease.
“The idea with all of this work is to understand, first, the genetic changes, and to identify the people with the highest risk of melanoma,” Professor Mann said.
Once identified, such people could then watch their skin more closely, to catch melanoma when it first appeared, he said.
The researchers made the findings by sequencing the entire genome of someone from a family that had recorded eight melanoma cases and which had tested negative for the only other two genes previously linked to melanoma, CDKN2A and CDK4.
When this process pointed the finger of suspicion at MITF, the researchers then sequenced the remaining seven people from the same family still available for study, and found the MITF mutation in three out of seven that had developed melanoma.
Cancer Council Australia’s Terry Slevin said the findings were “a worthwhile and a potentially useful discovery”, with the next step being to develop a reliable test that identifies who has the higher risk in the families where melanoma is common.