We have known for a while that people with red hair, fair skin and freckles were at greater risk for skin cancer. Now new research not only tells us why, but is also warning us that our red-haired friendshave a much higher risk for melanoma, the deadliest form of skin cancer.
The research, published in Nature Communications, showed that even a single copy of a red hair-associated MC1R gene variant increased the number of mutations in melanoma, the most serious form of skin cancer. Many non-red haired people carry these common variants and the study shows that everyone needs to be careful about sun exposure.
Red-headed people make up between one and two percent of the world’s population. They have two copies of a variant of the MC1R gene which affects the type of melanin pigment they produce, leading to red hair, freckles, pale skin and a strong tendency to burn in the sun.
The study unexpectedly showed that people with only a single copy of the gene variant still have a much higher number of tumor mutations than the rest of the population.
The researchers, from the Wellcome Trust Sanger Institute and University of Leeds, analyzed publicly available data-sets of tumor DNA sequences collected from more than 400 people. They found an average of 42 per cent more sun-associated mutations in tumors from people carrying the gene variant.
Exposure to ultraviolet light from either sunlight or sunbeds causes damage to DNA and it has been thought that the type of skin pigment associated with red-heads could allow more UV to reach the DNA. While this may be one mechanism of damage, the study also revealed that the MC1R gene variation not only increased the number of spontaneous mutations caused by ultraviolet light, but also raised the level of other mutations in the tumors. This suggests that biological processes exist in cancer development in people with MC1R variation that are not solely related to ultraviolet light.
The research explains why red-haired people have to be so careful about covering up in strong sun. It also underlines that it isn’t just people with red hair who need to protect themselves from too much sun. People who tend to burn rather than tan, or who have fair skin, hair or eyes, or who have freckles or moles are also at higher risk.