The MC1R gene variant is associates with red hair, pale skin and freckles. We are all aware of the damage over exposure to the sun can cause and the need to be careful about sun exposure. Pale-skinned people have to be extra careful as they have a strong tendency to burn in the sun. Many non-red haired people carry a single copy of the MC1R gene variant, but red haired people have two copies. The gene affects the type of melanin pigment produced and two copies leads to freckles, pale skin and red hair.
In a study done at the Wellcome Trust Sanger Institute and University of Leeds, researches have for the first time linked these gene variants to a higher number of genetic mutations in skin cancers. Melanoma is the most serious form of skin cancer and even a single copy of the MC1R gene variant increases the number of mutations that can occur in this cancer.
Although it has been known for quite some time that an increased likelihood of developing skin cancer is present in a person with red hair, this is the first time that it has been proven that the gene is associated with more mutations of skin cancers. The effect on people with the variant is comparable to an additional 21 years of sun exposure in a person without the gene variant.
Joint lead researcher of the study, Dr David Adams, notes that even people with only a single copy of the gene variant have more tumor mutations than people without. Between one and two percent of the world’s population are redheaded, but this unexpected finding means that the number of people affected is far higher than originally thought.
Adam thinks the study could go a far way in better identifying people with a higher risk of developing skin cancer. As the research is one of the first examples of a common genetic profile, it is likely to have a large impact on this specific cancer genome.
The research underlines that people who have freckles or moles, fair skin, eyes or hair and tend to burn rather than tan are also at higher risk, Dr Julie Sharp, head of health and patient information at Cancer Research UK, observes. This group needs to be as careful about covering up in strong sun as red-haired people.
Damage to DNA is caused not only by exposure to ultraviolet light from the sun, but also from sunbeds. With redheads, their type of skin pigment could allow more UV to reach the DNA. The study also revealed that although this is one mechanism of how the damage is caused, the MC1R gene variation also raises the level of other mutations in the tumors, in addition to an increase in the number of spontaneous mutations. From this, it can be concluded that biological processes exist in cancer development in people with the MC1R gene variation that are related to sources other than ultraviolet light.
According to Professor Tim Bishop, Director of the Leeds Institute of Cancer and Pathology at the University of Leeds, this study has significant implications for understanding how different skin cancers form. Tumor DNA sequences collected from more than 400 people show that approximately 42% more tumor mutations are found in people carrying the MC1R gene variant, whether they are red-haired or not.
At the end of the day, we still all need to protect ourselves from the sun, whether we have the gene variant or not.
The research was published in the journal Nature Communications.