More accurate prediction models of skin cancer risk can be designed by combining data on individuals’ lifetime sun exposure and their genetics, according to a study presented at the American Society of Human Genetics (ASHG) 2018 Annual Meeting in San Diego, Calif.
The investigation was conducted by researchers from 23andMe Inc., a company that provides personal genetic testing for individuals interested in learning more about their ancestry. Genetic and survey data from 210,000 research participants of European descent were analyzed to identify correlations between previously known and potentially novel skin cancer risk factors and the occurrence of three forms of skin cancer: melanoma, basal cell carcinoma (BCC), and squamous cell carcinoma (SCC).
Investigators concluded that although insignificant as independent variables, multiple risk factors can be combined into statistical models that are more informative.The best-performing models incorporated a genetic risk score composed of data on up to 50 genetic variants, along with: family history, body mass index (BMI), skin pigmentation and sensitivity, number of moles, estimated current sun exposure, and sunbathing frequency before the age of 30.
Researchers used data obtained with consent from users of 23andMe.
Photo by Gustavo de Cunha Pimenta via https://goo.gl/UieNBG.
Notably, researchers reported that genetic factors alone accounted for 8.3 to 15.2% of the variance explained in skin cancer risk. Although the three skin cancers have different physiology, frameworks did not find fundamental differences between the three cancer types. They also did not reveal strong interaction between genetic and environmental risk factors.
That being said, while the self-reported nature of the survey data allowed researchers to collect a large dataset, it also presented some challenges.
“Measuring lifetime exposure is generally challenging,” said Dr. Pierre Fontanillas, PhD, senior statistical geneticist at 23andMe Inc. in Mountain View, Calif., in a press release. “It is particularly hard to capture sun exposure and when in life it happened, and it may be that some of the other correlates we found, like higher BMI, reflect a lack of outdoor activity rather than being directly correlated with risk of skin cancer.”
In future studies, the researchers will replicate the trial in sample populations with non-European heritage. They are also exploring alternative techniques of calculating genetic risk score and measuring sun exposure, with the goal of developing risk estimates accurate enough to be used by clinicians and patients.