It’s not just sun exposure that makes fair-skinned people more vulnerable to melanoma skin cancer. Researchers have found the type of skin pigment predominantly found in light-skinned blonds and redheads may itself boost the risk of developing deadly melanoma — regardless of their exposure to ultraviolet radiation from sunlight.
The surprising findings, published in the journal Nature by Massachusetts General Hospital scientists, suggest simply using sunscreen and avoiding sunburn may not be enough to protect such individuals from skin cancer. It could also pave the way for more effective sunscreens and other approaches to reduce the risk of melanoma and other skin cancers in those most at risk.
"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 … identify a new mechanism to help explain it," said lead researcher Dr. David Fisher, chief of the MGH Department of Dermatology.
"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 defense against melanoma and other skin cancers."
Fisher and his colleagues noted two main types of the pigment melanin are found in human skin: a dark brown or black form called eumelanin, predominantly in individuals with dark hair or skin; and a lighter pigment called pheomelanin, predominantly in individuals with red or blond hair, freckles, and fair skin.
Red/blond melanin is known to be less effective than dark melanin in shielding against UV damage, but the MGH study found the higher rate of melanoma in fair-skinned individuals is not fully explained by limited UV protection. In fact, researchers said, such individuals face higher melanoma risks in areas of the skin that are not exposed to sunlight at all. What’s more, available sunscreens are not as effective in protecting against melanoma in fair-skinned people.
Although the MGH study involved mice, Fisher said the findings have significant implications for fair-skinned people.
"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," he added. "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."
The study was funded, in part, by the National Institutes of Health.