People in the UK have more DNA-damaged facial skin from the sun than those living in Singapore, British researchers reported last night.
This study, which looked at keratinocyte cancers, could help to explain why there is a higher risk of developing the most common skin cancers in the UK.
Led by the Wellcome Sanger Institute and collaborators at the Skin Research Institute of Singapore (SRIS), the research compared the mutational landscape of normal facial skin between individuals from the UK and Singapore.
This showed that Northern European skin types in the UK have four times the burden of DNA mutations than the average skin type found in Singapore and that most of the DNA mutations accumulated in Northern European skin types in the UK are due to UV light. In Singapore mutations are mainly due to usual ageing processes.
The findings, published in Nature Genetics, may help in developing personalised approaches to sun protection and skin cancer prevention in different populations.
The team collected tissue samples from patients undergoing routine surgery to remove excess eyelid or eyebrow skin and sequenced the outermost layer of skin to identify genetic alterations, focusing on 74 genes commonly mutated in cancers.
They analysed more than 400 samples and compared tissue from five donors in Singapore with published sequencing data from six UK donors.
The mean donor age from Singapore was 62 years old and 68 in the UK.
Eyelid skin in the UK cohort had four times as many cancer-associated DNA mutations, particularly those affecting known cancer genes, such as TP53, and 15% of UK skin cells had damage to the p53 protein compared to just 5% of Singaporean skin cells.
An abnormal number of chromosomes were detected in 13% of cells in UK skin, compared to 1% of cells in Singapore.
Nearly every cell in the UK donor skin, from individuals aged over 60, had a mutation in a cancer-associated gene.
First study author Dr Charlotte King, of the Wellcome Sanger Institute, said: “These findings help us understand why the UK has such a high incidence of keratinocyte skin cancers.
“We hope our study encourages others to look at further diverse populations – across the spectrum of cancer risk – for clues on how we can better prevent this common cancer. Pigmentation in the skin can protect cells from UV rays, but other differences, like how the body copes with inflammation, may explain variation in cancer risk from person to person. Studying populations at a lower cancer risk can teach us about protective mechanisms that already exist in nature.”
King C, Lane B, Jones PH et al. Somatic mutations in facial skin from countries of contrasting skin cancer risk. Nature Genetics 3 August 2023; doi: 10.1038/s41588-023-01468-x.
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