Genes linked to red hair and freckles are closely linked to mutations that cause melanoma, British researchers reported last night.
The findings help explain the known link between red hair, pale skin and risk of skin cancer.
The researchers say the genetic susceptibility is more than just vulnerability to ultra-violet light.
Researcher Dr David Adams, of the Wellcome Trust Sanger Institute, Cambridge, UK, explains: "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."
About 6% of the UK’s population has red hair, due to carrying two copies of a variant of the MC1R gene. This affects the type of melanin pigment produced by the body.
The team analysed large datasets of tumour DNA sequences taken from over 400 patients. There were approximately 42% more sun-associated mutations in tumours from people carrying this gene variant.
They calculate that the burden of mutations associated with these variants is comparable to an extra 21 years of sun exposure. Full details appeared in Nature Communications yesterday (12 July).
Dr Adams added: "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. 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."
Co-author Professor Tim Bishop of Leeds University, UK, added: "This study has significant implications for understanding how skin cancers form. The tumours were sequenced in the USA, from patients all over the world and the data was made freely accessible to all researchers."
Robles-Espinoza, C. D. et al. Germline MC1R status influences somatic mutation burden in melanoma. Nature Communications 12 July 2016 doi: 10.1038/NCOMMS12064
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