Melanoma onset was delayed by applying sun protection factor 30 (SPF30) sunscreen prior to exposure to ultraviolet-B (UVB) light in a mouse model of the disease, according to data presented at the American Association for Cancer Research 2016 Annual Meeting.1
Sunscreen is known to prevent skin burns, but its effects on skin cancer had not been previously investigated in a systematic way.
“Over the past 40 years, the melanoma incidence rate has consistently increased in the United States,” said Christin Burd, PhD, an assistant professor in the Department of Molecular Genetics and the Department of Molecular Virology, Immunology & Medical Genetics at The Ohio State University Comprehensive Cancer Center – Arthur G. James Cancer Hospital in Cleveland.
“Sunscreens are known to prevent skin from burning when exposed to UV sunlight, which is a major risk factor for melanoma. However, it has not been possible to test whether sunscreens prevent melanoma because these are generally manufactured as cosmetics and tested in human volunteers or synthetic skin models.
“We have developed a mouse model that allows us to test the ability of a sunscreen to not only prevent burns but also to prevent melanoma,” continued Burd. “This is a remarkable accomplishment. We hope that this model will lead to breakthroughs in melanoma prevention.”
The researchers used mice that were genetically engineered to spontaneously develop melanoma approximately 26 weeks after the chemical 4-hydroxytamoxifen (4OHT) is applied to the skin and UVB light exposure occurs. The team then tested a number of sunscreens on these mice prior to exposure to UVB light. They found that all the SPF30 sunscreens delayed melanoma onset and reduced tumor incidence.
“There were some minor differences in melanoma prevention amongst the different SPF30-labeled sunscreens,” said Burd. “However, we later discovered that even though the sunscreens were all marketed as SPF30, some were actually predicted to have a higher rating. For this reason, it is hard to compare the melanoma-preventing capacity of the different sunscreens at this time.”
The researchers plan to continue their study, with the goal of isolating which specific sunscreen ingredients provide strongest protection against melanoma development. Burd stated that this will allow the development of smarter sunscreens that are both safe to use and proven effective in reducing skin cancer risk.
1. Holderbaum AM, Hennessey RC, James E. Gillahan JE, et al. In vivo modeling of NRAS-mutant melanoma reveals differential preventative efficacy amongst SPF30 sunscreens. Presentation at: American Association for Cancer Research 2016 Annual Meeting; April 16-20, 2016; New Orleans, LA. Abstract 900.