People with red hair are more susceptible to developing skin cancer, new research suggests.
Researchers have discovered that gene variants associated with red hair, pale skin and freckles are linked to a higher number of genetic mutations in skin cancers.
The effect equates to an extra 21 years of sun exposure in people with red hair, experts said.
People with red hair make up between 1-2% of the world’s population and about 6% of the UK population.
They have two copies of a variant of the MC1R gene which affects the type of melanin pigment they produce. This leads to red hair, freckles, pale skin and a tendency to burn in the sun.
They analysed data-sets of tumour DNA sequences from more than 400 people and discovered an average of 42% more sun-associated mutations in tumours from people carrying the MC1R gene variant.
They also found that even a single copy of a red hair-associated MC1R gene variant increased the number of mutations in melanoma skin cancer, the most serious form of skin cancer.
However researchers said many people carry these common variants, regardless of whether they have red hair or not, so everyone needs to be careful when out in the sun.
Dr David Adams, joint lead researcher at the Wellcome Trust Sanger Institute, 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.”
Dr Julie Sharp, head of health and patient information at Cancer Research UK, hailed the research as “important”.
She said 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,” she said.
“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.”
The research was published in the journal Nature Communications.