How 'red hair' gene raises skin cancer risk!

London: Gene variants associated with red hair, pale skin and freckles may be linked to skin cancer, according to a new study which suggests that the burden of mutations associated with these variants is comparable to an extra 21 years of sun exposure in people without this form.

The findings by researchers from Wellcome Trust Sanger Institute and University of Leeds in the UK showed that even a single copy of a red hair-associated MC1R gene variant increased the number of mutations in melanoma skin cancer; 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, researchers said.

For the first time, they proved that gene variants associated with red hair, pale skin and freckles are linked to a higher number of genetic mutations in skin cancers.

The burden of mutations associated with these variants is comparable to an extra 21 years of sun exposure in people without this variant, researchers said.

Red-headed people make up between one and two per cent 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, they said.

"It has been known for a while that a person with red hair has an increased likelihood of developing skin cancer, but this is the first time that the gene has been proven to be associated with skin cancers with more mutations," said David Adams from Sanger Institute.

"Unexpectedly, we also showed that people with only a single copy of the gene variant still have a much higher number of tumour mutations than the rest of the population," said Adams.

"This is one of the first examples of a common genetic profile having a large impact on a cancer genome and could help better identify people at higher risk of developing skin cancer," he added.

Researchers analysed publically available data-sets of tumour DNA sequences collected from more than 400 people. They found an average of 42 per cent more sun-associated mutations in tumours from people carrying the gene variant.

Exposure to ultraviolet (UV) 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, researchers said.

While this may be one mechanism of damage, the study also showed 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 tumours.

This suggests that biological processes exist in cancer development in people with MC1R variation that are not solely related to UV light, researchers said.

The findings were published in the journal Nature Communications.