Scientists are a step closer to understanding why people with the genes for red hair have a greater risk of developing the potentially deadly skin cancer melanoma.
Research has revealed that patients with the genes for red hair have more mutations in their skin cancer than those without.
“We have known for a while that there is an association between these [genetic] variants that cause red hair and increased risk of melanoma,” said David Adams, a co-author of the research from the Wellcome Trust Sanger Institute. “What this really does is show at least a contributing factor to that is more mutations.”
Red hair, fair skin and a sensitivity to the sun are down to variations in a gene called MC1R that affects the production of pigments, called melanins, in the skin.
“People with red hair have a different type of melanin than people who don’t have red hair - and the type of melanin that redheads have is less able to protect them from the sun,” said Adams.
About 6% of the UK population have two copies of the MC1R gene variant and hence have red hair, while around 25% of the UK population have only one copy and are typically not redheads. But the new research reveals that patients in both groups show the same number of mutations in their skin cancer.
The scientists say the findings suggests people with just one copy of the gene might be more susceptible to the damaging effects of sunlight than previously thought.
Writing in the journal Nature Communications, an international team of researchers describe how they analysed existing genetic data and samples from 405 melanoma patients.
The scientists found that melanoma patients with redhead gene variants had a greater number of mutations in their skin cancer than those without, with 42% more sun-associated mutations alone.
But while previous research has shown that the chance of developing melanoma is linked to the number of copies of the redhead gene variants a person has, the new study has thrown up a puzzle.
“We don’t understand why persons with two MC1R variants are more likely to develop melanoma than those with only one variant, because our [new] data suggest they accumulate mutations at the same rate,” said Tim Bishop, co-author of the study from the University of Leeds.
The findings, he says, have important implications. While redheads might already dodge the sun’s rays, those with only one copy of gene may not realise that they are at risk from the sun’s damaging effects.
Adams agrees. “I think there is a general public health message here that there’s a high proportion of the population who need to be careful in the sun,” he said.
Dr Julie Sharp, head of health and patient information at Cancer Research UK, which co-funded the research, said: “This important research explains why red-haired people have to be so careful about covering up in strong sun. It also underlines that it isn’t just people with red hair who need to protect themselves from too much sun. People who tend to burn rather than tan, or who have fair skin, hair or eyes, or who have freckles or moles are also at higher risk.
“For all of us the best way to protect skin when the sun is strong is to spend time in the shade between 11am and 3pm, and to cover up with a t-shirt, hat and sunglasses. And sunscreen helps protect the parts you can’t cover; use one with at least SPF15 and four or more stars, put on plenty and reapply regularly.”
