New research suggests that a pigment in redheads' skin may play an active role in the development of skin cancer.
It is well known that redheads are three times more prone to skin cancer than those with a darker skin type, as they have less protection against the sun's rays.
However, the findings of a recent study published in Nature have revealed the melanoma risk to redheads also applies to areas of their skin not exposed to sunlight.
"We've known for a long time that people with red hair and fair skin have the highest melanoma risk of any skin type. These new findings do not increase that risk but identify a new mechanism to help explain it," said David Fisher, the paper's senior author, in a statement.
"This may provide an opportunity to develop better sunscreens and other measures that directly address this pigmentation-associated risk while continuing to protect against UV radiation, which remains our first line of defence against melanoma and other skin cancers."
In tests, the researchers found that mice who had their 'redhead' pigment pathway removed were much less likely to develop cancer, indicating that the pigment itself was leading to melanoma.
"Right now we're excited to have a new clue to help better understand this mystery behind melanoma, which we have always hoped could be a preventable disease," Dr Fisher said, in a statement.
"The risk for people with this skin type has not changed, but now we know that blocking UV radiation –- which continues to be essential –- may not be enough.
"It will be important for these individuals to be aware of changes in their skin and never hesitate to have something checked by a dermatologist, even if they have scrupulously protected themselves from sun exposure, which we continue to encourage.
"About six out of seven melanomas will be cured if they are found early, so we need to heighten awareness and caution."