November 1, 2012
Pigment Of Red Haired And Fair Skinned People Adds To Melanoma Risk
Connie K. Ho for redOrbit.com — Your Universe Online
Researchers from Massachusetts General Hospital (MGH) Cutaneous Biology Research Center (CBRC) and Cancer Center recently discovered that a kind of pigment found in individuals with red hair and fair skin may affect the development of melanoma.
The scientists explained how various forms of the pigment melanin could be found in the skin. While eumelanin, a black or dark form of melanin, could be found in people with darker hair or darker skin, pheomelanin, a lighter pigment of blond-to-red, could be found predominantly in people who had freckles, light skin and red hair. While red/blond melanin is thought to not be as protective against Ultraviolet (UV) rays as dark melanin, it is thought that products like sunscreen are less effective against protecting the body from melanoma as opposed to other forms of skin cancer.
"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 do not increase that risk but identify a new mechanism to help explain it," remarked the study´s senior author Dr. David Fisher, the director of the CBRC, in a prepared statement. "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."
In the study, the researchers utilized two groups of mice who were genetically identical except for a gene that managed the type of melanin produced. One group had the gene that led to a predominance of dark melanin. The other group of mice had the gene that was related to light skin and red hair in humans. With a method that activated the melanoma-related form of the BRAF oncogene in parts of the skin pigment cells of the mice, the researchers found that half of the red mice had developed melanoma while fewer dark mice had developed the cancer
Based on the findings, the scientists started to probe whether the red pigment could be carcinogenic. When they removed the red-pigment pathway from the mice, they found that this protected the mice from forming melanoma and that somehow an element of the pigment was causing the formation of melanoma. They then looked more carefully at the skin of red and albino mice, and determined that the melanoma risk was associated with the generation of unstable oxygen-containing molecules that damaged cells—these molecules are known as reactive oxygen species (ROS).
The team of investigators believes that more research is needed to find effective and safe ways to reduce melanoma risk related to the red pigment.
"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," continued Fisher, who serves as chief of the MGH Department of Dermatology, in the statement. "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 results of the study were recently published in an article that received advanced online publication in the journal Nature.