The type of skin pigment found in red-haired and fair-skinned people may contribute to the development of melanoma, a finding which could lead to new skin cancer prevention methods, a study has found.
The researchers at the Massachusetts General Hospital say the elevated risk of melanoma among people with red hair and fair skin may be caused by more than just a lack of protection against UV radiation.
In their study for additional contributors to melanoma development, the team used strains of mice that were nearly identical genetically except for the gene that controls the type of melanin produced.
One group of dark-coloured mice had the typical variant leading to a predominance of dark melanin.
Another group of mice had a "red hair-fair skin" version, the same variant that produces red hair and fair skin in humans.
The researchers used a method devised by co-authors at the University of California, San Francisco and Yale University to activate the melanoma-associated form of the BRAF oncogene in patches of the animals' skin pigment cells, with the expectation that an additional environmental stress like UV radiation would be needed to induce melanoma formation.
They were surprised to find that within months, half of the red mice had developed melanomas, while only a few dark mice had.
"We've known for a long time that people with red hair and fair skin have the highest melanoma risk of any skin type," said David Fisher, senior author of the paper in the science publication Nature.
"These new findings do not increase that risk but identify a new mechanism to help explain it.
"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."