A gene variant carried by people with red hair, pale skin and freckles may boost skin cancer risk even without exposure to the sun's rays, researchers said Tuesday.
The risk, rather surprisingly, is also higher for people who possess the genetic DNA signature but not the telltale physical traits, reported the international team.
The findings, published in the journal Nature Communications, are based on a genetic analysis of skin cancer tumors from more than 400 people.
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It revealed that tumors from people with a redhead variant of the MC1R gene had 42 percent more mutations -- the equivalent of 21 years of additional Sun exposure in people without it.
Though most gene mutations are innocuous, the more that occur, the more likely a normal human cell will be to change into a cancer cell.
The findings suggested that people with an MC1R variant are more susceptible to mutagenic processes, such as UV exposure for example, that can trigger skin cancer, known as melanoma.
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"This work is significant because its conclusions apply to a high proportion of the population, those people that carry at least one copy with a genetic variant in MC1R," study co-author David Adams of the Wellcome Trust Sanger Institute told AFP.
In some countries, such as England and Ireland, this could be as much as a third of the population -- though only about one or two percent of all people have red hair.
Many of those at risk will not even know that they carry the variant, said the researchers.
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