Red hair and freckles directly linked to skin cancer risk

An inherited “ginger gene” associated with red hair, pale skin and freckles is directly linked to the genetic risk of developing skin cancer, new evidence has shown for the first time.

The MC1R gene variant can boost the risk of skin cancer by the equivalent of 21 extra years of sun exposure, say scientists.

Red-haired people all have two copies of the variant, which causes a strong tendency to burn in the sun.

But even a single copy of the variant, found in many people without red hair and freckles, increases the number of gene mutations associated with malignant melanoma, the deadliest form of skin cancer, research shows.

Redheads are disproportionately represented in Ireland, making up more than 6 per cent of the population, compared with 1 per cent to 2 per cent of the rest of the world.

The MC1R variant affects the type of melanin skin pigment humans produce, leaving those who have it especially vulnerable to damage from the sun’s ultraviolet (UV) rays.

Lead researcher Dr David Adams, from the Wellcome Trust Sanger Institute in Hinxton, Cambridgeshire, said: "It has been known for a while that a person with red hair has an increased likelihood of developing skin cancer, but this is the first time that the gene has been proven to be associated with skin cancers with more mutations.

“Unexpectedly, we also showed that people with only a single copy of the gene variant still have a much higher number of tumour mutations than the rest of the population.

“This is one of the first examples of a common genetic profile having a large impact on a cancer genome and could help better identify people at higher risk of developing skin cancer.”

The scientists analysed datasets of skin tumour DNA sequences collected from more than 400 people.

They found an average of 42 per cent more sun-associated mutations in tumours from people carrying the MC1R gene variant.

MC1R gene

Prof Tim Bishop, joint lead author and director of the Leeds Institute of Cancer and Pathology at the University of Leeds, said: "This is the first study to look at how the inherited MC1R gene affects the number of spontaneous mutations in skin cancers and has significant implications for understanding how skin cancers form.

“It has only been possible due to the large-scale data available. The tumours were sequenced in the US, from patients all over the world and the data was made freely accessible to all researchers.

“This study illustrates how important international collaboration and free public access to datasets is to research.”

UV rays, either from sunlight or artificially generated for sunbeds, damage DNA.

People with red hair have a skin pigment that is thought to allow more of the rays to penetrate their DNA, potentially increasing the risk.

The new study, published in the journal Nature Communications, confirmed that the MC1R gene variant raised the number of spontaneous mutations in the skin caused by UV rays.

Unexpectedly, it was also found to boost levels of other skin tumour mutations not related to UV exposure - suggesting involvement of the variant in cancer processes not driven by sunlight.

Dr Julie Sharp, head of health and patient information at the charity Cancer Research UK, 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 4 or more stars, put on plenty and reapply regularly.”

PA