With summer here again, many people will be jetting off to sunny locations to top up their tans. Public health campaigns have had a lot of success in encouraging sunbathers to wear sunscreen, to cut down their UV exposure and protect themselves from skin cancer. However, newly published research has shown that sunscreen alone can only delay, not prevent, melanoma, a particularly dangerous skin cancer type.
Melanoma is the most malignant form of skin cancer. In the US it accounts for less than 2% of all skin cancer cases, but causes the vast majority of skin cancer deaths. Melanoma incidence rates in the US have been rising over the last 30 years, and it is estimated that this year alone over 76,000 new US cases of melanoma will be diagnosed. Melanoma is also a problem in other countries around the world, for example it’s the fifth most common cancer in the UK with over 13,000 new cases each year. Risk factors for melanoma and skin cancer in general include sun sensitivity, a history of excessive sun exposure, and sunburn. The general public has been encouraged to wear sunscreen to prevent skin cancer, and many think this alone is enough to protect their skin. A new study published this month in Nature has shown that this is not the case.
The new study looked specifically at mice with a V600E substitution in BRAF, an acquired mutation found in around half of early stage human melanomas. Part of the study compared melanoma rates in these mice following repeated exposed to UV light, either with or without sunscreen (UVA superior, UVB SPF 50). For mice without sunscreen, all developed melanoma within 7 months, with an average of 3.5 tumors each. For the mice protected with sunscreen, development of melanoma was delayed but did still happen in all of the mice. Tumors developed within 15 months, with an average of 1.5 tumors each.
The study also identified the novel mechanism by which melanomas were occurring – mutations in the Trp53 protein. The TP53 gene is known to play a role in human non-melanoma skin cancer, but up to now it had not been thought to be a major player in human melanoma. This study showed that Trp53 mutations acquired through UV damage cooperated with the BRAF V600E mutation in mice to promote melanoma. Sunscreen was shown to reduce the number of mutations in Trp53, but again did not prevent them completely.
These results now need to be clinically validated in humans, particularly in those who have developed the BRAF mutation. In the meantime, Crown Bioscience agrees with the authors of this study that sunscreen should be combined with other sun avoidance strategies such as wearing a hat, loose clothing, and avoiding sun exposure at the hottest times of the day.
Crown Bioscience supports melanoma research through the use of our clinically relevant Xenograft and Patient-Derived Xenograft models available for drug discovery and translational sciences. Our comprehensive and easily searchable online databases, HuBase™ and XenoBase™, allow researchers to quickly find CDX and PDX models with specific mutations, such as BRAF V600E, for targeted research programs. Contact us today at firstname.lastname@example.org to discover how we can transform your melanoma and targeted therapy research.