Scientists close in on new skin cancer gene

Cancer Research UK scientists have found the location of an important new gene which pre-disposes people to skin cancer, according to a study published today.

Researchers from the charity are part of the international team close to isolating the gene, which they have found to sit on a tiny part of chromosome 1 – one of the bundles of DNA containing our genes.

Inheriting a faulty version of the gene is thought to give people a much higher than average chance of developing malignant melanoma – the most dangerous form of skin cancer – and may be responsible for up to a third of inherited cases.

Scientists believe the study provides a valuable insight into the way in which melanoma develops, and in the future, will help doctors to identify, monitor and advise those more susceptible to the disease to help them reduce their risk.

The most important cause of melanoma is exposure to the sun, but scientists think that, in around 10 per cent of cases, inherited genes play a role.

Past research has already identified two genes – CDKN2A and CDK4 – which increase a person’s risk of melanoma when inherited in a faulty form. But scientists know other genes are likely to exist because CDKN2A and CDK4 only account for around 30 per cent of inherited cases.

“Sun exposure causes damage to the skin’s DNA and accumulation of this damage can lead to cancer. Some people may inherit an increased susceptibility to melanoma and for these individuals avoiding the sun’s rays becomes even more important,” says Dr Julia Newton-Bishop, part of the husband and wife team who worked on the study, from the Cancer Research UK Clinical Centre at St James University Hospital in Leeds.

“High risk genes for breast cancer have been identified and well researched and we are running an international effort to discover similar genes for melanoma – a disease that is becoming increasingly more common,” she adds.

The team searched for new risk genes by analysing genetic data from around 80 Australian, European and American families, with three or more cases of melanoma, that weren’t caused by a faulty version of either the CDKN2A or CDK4 genes.

They found that a number of the families had the particular stretch of DNA on chromosome 1 in common and had inherited it in a pattern that matched the inheritance of melanoma.

The team looked specifically at families where individuals had developed melanoma at an early age – a sign that the disease is inherited rather than being caused by damage to genes during a person’s lifetime. They found those families with the earliest age of onset were most likely to carry this particular region on chromosome 1.

“We’ve narrowed down the location of the melanoma gene to a tiny piece of DNA, which puts us one step away from finding the gene itself,” says Professor Tim Bishop, from the Cancer Research UK Clinical Centre in Leeds.

“We believe the gene we are close to finding is one of the major risk genes for melanoma and could be responsible for around 30 per cent of inherited cases,” he adds.

But Dr Newton-Bishop warns: “We need to find out much more about the gene we’ve located in this study and other risk genes before we can begin to use the information in a clinical setting.”

Researchers say the more immediate implications of the study will be to open up new lines of work that look at how damage to the gene affects the cell, leading to cancer. Understanding how this happens will help in the search for new treatments for the disease.

Cancer Research UK’s Head of Clinical Programmes, Dr Richard Sullivan, says: “There has been a great deal of focus on identifying high-risk genes for breast cancer but we have much less information about the genetic basis of skin cancer and this study and further work by the team will help to address this gap.

“In the future we should be able to test for key genes that increase the risk of melanoma, accurately identifying those with a high chance of developing the disease. Doctors could use such information to monitor high-risk people for the early signs of skin cancer and advise them on lifestyle changes to lower their risk.”

ENDS