Genes show how much sun exposure could lead to melanoma
Researchers at QIMR Berghofer in Australia have found 22 different genes which could help determine how much sun exposure it will take before a person develops melanoma. Results of the study were published online ahead of print in the British Journal of Dermatology (Nov. 21, 2019).
For those at high genetic risk, sun exposure in childhood is a strong contributing factor while people at low genetic risk develop melanoma only after a lifetime of exposure to sunlight.
Australia has the highest rates of skin cancer in the world. Each year more than 12,000 Australians are diagnosed with invasive melanoma.
Dr. David Whiteman, the study’s lead author, and head of QIMR Berghofer Medical Research Institute’s Cancer Control Group said the study used data from QSkin, the world’s largest genetic study of skin cancer, to explore how genes and sun exposure affected a person’s chances of developing melanomas.
“The study findings suggest that people with genes that predispose them to skin cancer only need modest levels of exposure to Australia’s sunny climate to develop this disease,” Dr. Whiteman said in a press release.
“Our data show that people who are born and grow up in Australia have a 50 per cent increased risk of melanomas, while those migrating to Australia as adults, who have the same genes are less likely to develop the deadly disease.”
The study confirmed that sun damage leading up to the age of 20 is more harmful for those with a higher genetic risk since it is enough to trigger melanomas and they do not require long, cumulative exposure.
Dr. Whiteman notes that those who do not carry the higher risk genes associated with skin cancer can still develop melanomas—they require more exposure to sunlight over the course of their lifetime.
According to QSkin study project manager, Dr. Catherine Olsen, the researchers looked at genetic and behavioural factors in the data to determine melanoma risk. The QSkin data included information such as place of birth, age at migration, sunburns and hours spent in the sun. Additionally, researchers took into consideration histories of squamous cell carcinoma, basal cell carcinoma and sunspots.
The study followed the subjects from 2011 and learned about their melanoma diagnoses from the cancer registry allowing the researchers to work out risks.
Dr. Olsen is hoping the study’s results will encourage more to sign up to participate in QIMR Berghofer’s QSkin genetics study, which aims to better understand the role genes play in the disease.
“We want to dig deeper into what genes are involved in skin cancer, and that’s why we want more recruits for QSkin,” said Dr. Olsen. “More than 5, 000 people have recently signed up to provide DNA for the study but our goal is 20,000 Australians by this time next year.
“While this study provides an insight into the development of melanoma and may help in identifying people who would benefit from targeted sun protection messaging, more still needs to be done to understand this disease that affects more Australians than any other population in the world.”