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Alack of natural protection against ultraviolet (UV) radiation in people with red hair and fair skin has long been considered a risk factor for melanoma. However, according to researchers at Massachusetts General Hospital (MGH) in Boston, another factor may contribute to the disease: the red/blond pigment itself.1

The finding helps explain a mechanism that may lead to the disease in people with this skin pigment, called pheomelanin, says David Fisher, MD, PhD, chief of the department of dermatology at MGH and senior author of the study. Pheomelanin is less effective than dark melanin in blocking UV damage. According to the study authors, additional research has shown that increased nonmelanoma skin cancer risk is limited to areas that have been exposed to the sun, but melanoma risk can be associated with areas of the skin that are not sun-exposed.

Oxidative Damage May Be Underlying Cause

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  2. Oxidative Damage May Be Underlying Cause
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In the MGH study, investigators compared 2 groups of mice: 1 with the dark-skin pigment and the other with the red-hair/fairskin type. They then activated the melanoma-associated form of the BRAF oncogene in patches of the animals' skin pigment cells, assuming that UV radiation would need to be used to induce melanoma. Instead, they found that within months, onehalf of the mice with the red-hair/fairskin type had developed melanomas whereas only a few of the mice with the dark-skin pigment had.

Because no UV radiation was involved, researchers began to wonder whether the pheomelanin pigment itself might be carcinogenic. As a result, they tested a group of red-haired/fairskinned mice in which all pigment production was genetically disabled (“albino redheads”). They found that removing that pigment pathway protected the mice from melanoma formation. They later discovered elevated levels of a type of DNA damage typically produced in the skin of mice with pheomelanin but not in albino redheads, which supports the theory that oxidative damage may be the underlying cause of red pigment-associated melanoma.

Dr. Fisher says more research is needed to determine safe and effective ways to apply this knowledge to improve melanoma protection, but that antioxidant treatments may potentially help reduce risk.

Reference

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  2. Oxidative Damage May Be Underlying Cause
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