It’s well-known that red-haired, fair-skinned people are more susceptible to melanoma because the melanin in their skin is not able to protect them from ultraviolet radiation the way darker melanin does. However, recent research found that even skin not exposed to the sun is at greater risk for melanoma in redheads.
How is melanin different in redheads?
Melanin is a substance produced by the body that gives color to hair, skin and the iris of the eye. It’s long been known to help protect the skin from the sun. However, there are two types of pigment melanin, which we inherit in different proportions, that make up our hair, skin and eye color. Eumalinin is dark brown or black melanin, which is predominant in people with dark hair or dark skin.
Pheomelanin, which is lighter-blond-to-red melanin, is predominant in people with red hair, freckles and fair skin. It’s not a surprise that people with predominant eumalinin are better protected from UV radiation than those with predominant pheomelanin. But researchers found that there may be more to the story than just weaker UV protection in people with pheomelanin.
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How was the study done?
Researchers looked at two groups of mice with almost identical genes, except the gene that controls melanin. The first group had dark melanin and the second group had the “redhead” melanin. Each group underwent a previously discovered method of activating an oncogene associated with melanoma in patches of skin pigment cells in the mice. Researchers expected to find that melanoma would form only if the mice were exposed to UV radiation. They were wrong.
What did they find?
They found that within a few months, half of the “redhead” mice had developed melanoma compared to very few of the dark mice. They double-checked that none of the mice had been exposed to UV radiation and confirmed that they had not.
They then took the study a step farther by disabling the pigment production in the “redhead” mice, which created a strain of “albino redheads.” They found that the incidence of melanoma in these mice dropped dramatically.
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What does this mean?
The findings suggest there is something in the “redhead” pigment itself that encourages melanoma to develop. Researchers hypothesize that the pigment generates reactive oxygen species (ROS), which are unstable oxygen-containing molecules that cause cell damage, and it’s the oxidative stress that increases melanoma risk. They examined the skin of both the “redhead” mice and “albino redhead” mice, and found that the “redhead” mice had high levels of DNA damage produced by ROS, but the “albino redheads” did not. This could lead to potential antioxidant treatments to further protect redheads from melanoma. Researchers noted that the risk of melanoma for redheads has not changed, but that blocking UV radiation may simply not be enough protection.
n.p. (2012, November 2). "Skin Cancer Risk Among Redheads Higher Even Without Sun." Medical News Today. Retrieved from http://www.medicalnewstoday.com/articles/252365.php
Published On: November 12, 2012