The risks of sun exposure are getting skin deep.

Researchers at New York University's Langone Medical Center have unveiled a new study that concludes "UVA radiation damages the DNA in human melanocyte cells, causing mutations that can lead to melanoma." Melanocytes are the cells in our skin that contain pigment that protects us from the sun.

"For the first time, UVA rays have been shown to cause significant damage to the DNA of human melanocyte skin cells," says Moon-shong Tang, PhD, professor of environmental medicine, pathology and medicine at NYU School of Medicine. "And because melanocytes have a reduced capacity to repair DNA damage from UVA radiation, they mutate more frequently, potentially leading to the development of melanoma."

Lightly and darkly pigmented melanocytes were exposed to UVA radiation and assessed DNA damage and the capacity of these cells to repair damaged DNA. DNA damage was detected in all melanocyte cells and these cells were unable to repair the damage. Normal skin cells were also exposed to UVA light but no damage to their DNA was observed.

The study also revealed why melanoma can also develop in areas never exposed to sun -- think between your toes. Because melanocytes generally have a limited capacity to repair any DNA damage, they have a higher mutation frequency rate and are more susceptible to the development of melanoma-even without the effects of the sun.

"Melanoma, the deadliest form of skin cancer, continues to increase at a rate of 3 percent a year," says Dr. Tang. "This research highlights the necessity of limiting UVA radiation by avoiding excessive sunlight, tanning and sunbeds."

In case you haven't heard it enough this summer, try to stay out of the sun during peak hours (10am to 4pm), wear a hat and sunglasses, and always use sunscreen.

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