#skincancer and #genetics - the role of the sun damage in DNA mutations.

A previously unknown oncogene that is activated by ultraviolet (UV) light has been implicated in a considerable proportion of squamous cell carcinomas (SCCs) and in some melanomas as well, a new study shows. The research was published online September 7 in Nature Genetics.

A team from the Stanford University School of Medicine and from the Veterans Affairs Palo Alto Healthcare System, Palo Alto, California, identified recurrent point mutations concentrated at an UV signature "hotspot" in KNSTRN, a gene involved in helping cells divide their DNA equally during cell division, in 17-19% of SCCs. The same KNSTRN mutation was identified in approximately 5% of all melanomas sequenced as well. Mutations at this UV hotspot are not found in any of the other cancers investigated — they occur only in skin cancers, senior author Paul Khavari, MD, PhD, professor of dermatology, Stanford University School of Medicine, said in a briefing.

This study highlights the importance of sun protection because it makes it clear that a single mutation in a single gene can start a process of catastrophe for the genome, which has real implications for how careful people should be about the sun, even more than ever suspected. Analysis of mutation type showed that the majority of tumors had mutational profile characteristics of exposure to ultraviolet light. Once the DNA is damaged, it needs to be repaired, and that repair process is not always perfect. The wrong repair  can lead to mutations, which can result in cancer later.