Study finds risk of melanoma related more to propensity for moles than exposure to sunlight

An international team of researchers from several countries, including Australia, Canada and the United States, identified two genes that dictate the number of moles an individual will get, raising the risk of skin cancer. As Tim Spector, professor of genetic epidemiology at King's College London, explains: "The number of moles you have is one of the strongest risk factors for melanoma - stronger than sunshine. This paper shows that we found two important genes that control the number of moles you have. Those genes also give you an extra risk of melanoma."

As a result of their findings, the researchers believe that the warnings about the risk of sunbathing are overstated, emphasizing that that only a small percentage of melanoma cases are caused by sunlight. Says Dr. Veronique Bataille, a researcher at King's College, London, and dermatologist at West Hertfordshire NHS Trust: "As a dermatologist working in the melanoma field for nearly 20 years, I feel quite strongly that there is always an overemphasis on sunshine. You often read that nearly all melanomas are caused by sunshine - which is not supported by the evidence. The more research we do, the more we realize that sunshine is a small part of the puzzle." And she adds, "In any population you study across the world, if you are ‘moley' it is a very steady risk factor for melanoma, and it doesn't make any difference whether you live in Glasgow or Sydney or LA. Let's keep sunshine in the picture because it does make you age and causes wrinkles - we have never denied that. But let's move away from scaring people by saying they are going to die because they go in the sun."

In addition, the researchers believe that the "obsession" with the dangers of sun exposure has caused serious vitamin D deficiencies, leading to an increase in deaths from other cancers, osteoporosis, depression and premature aging. They suggest that health warnings would be more beneficial if they were aimed at people who have more than 100 moles and if those warnings focused on the importance of checking moles regularly for changes in shape, size and/or color. While melanoma is relatively rare, accounting for just 10 percent of all skin cancer cases, it causes the majority of skin cancer-related deaths. Over the past three decades, the worldwide incidence of the disease in populations of European descent has risen faster than any other type of cancer, with the World Health Organization estimating that globally, there are 132,000 new cases of melanoma each year.

News Release: Sun warnings overstated as science finds new clue to skin cancer http://www.timesonline.co.uk/tol/news/uk/health/article6690007.ece July 12, 2009