New research reveals natural sunlight prevents skin cancer, limits growth of cancer cells

• TUESDAY, Feb. 1 (HealthDayNews) -- In a perplexing finding, a new study suggests that exposure to sunlight may help people with melanoma live longer.
• And a second study found sunshine confers yet another cancer benefit: It may reduce the risk of developing non-Hodgkins lymphoma.
• "Sunlight is one of only 60 agents designated by the World Health Organization as an established human carcinogen," said Kathleen Egan, an associate professor of medicine at Vanderbilt University School of Medicine and lead author of an editorial accompanying the studies in the Feb. 2 issue of the Journal of the National Cancer Institute.
• The answer is that it might not be the sunlight per se that is responsible, but some other capacity of sunlight, specifically its role in vitamin D synthesis, Egan explained.
• People who scored high on three measures of sun exposure -- sunburn, high intermittent sun exposure and solar elastosis (a measure of skin damage due to the sun) -- and had high skin awareness were less likely to die.
• "It's possible that people who have genetic factors in the vitamin D receptor gene or other genes in that pathway are less able to metabolize vitamin D through sunlight or milk, and therefore have a much higher susceptibility to developing melanoma under low levels of sun exposure," she said.
• Regardless, the findings should not be seen as an invitation to bake in the sun. "It's clear and undeniable that the incidence of melanoma overall is higher in those with a history of childhood sunburn, of intermittent sun exposure, and of sun damage," Jamal said.
• The second study found that exposure to ultraviolet (UV) radiation reduced risk for non-Hodgkins lymphoma.
• The study authors, based in Sweden, looked at the history of UV exposure and other risk factors for lymphoma in 3,000 lymphoma patients and a similar number of controls.