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son dark, thick, oily skin gets fewer wrinkles than badly sun-damaged fair skin.

Even with frequent applications of sunscreen, sunbathers may be at risk for developing melanoma (the most serious form of skin cancer). In fact, skin cells can undergo changes not just by exposure to the sun's ultraviolet-B (UV-B) light (rays between 280 and 320 nanometers) but also light with longer wavelengths, including ultravio-let-A (UV-A) light.

In the past scientists had linked melanoma to damaged DNA because those who inherit a defect in their ability to repair DNA are more than 1,000 times more likely than others to get this type of cancer. Because DNA absorbs only UV-B energy, many researchers believed that only this type of light caused the damage. Others suspected UV-A light but lacked hard evidence of a link between the light and cancer.

While studying light exposure with fish susceptible to the development of melanoma, scientists at Brookhaven National Laboratory in Upton, New York, found that exposure to a wavelength of 365 nanometers (UV-A used in black lights) resulted in tumors in 38 of 85 fish tested. Of the 61 fish treated with violet light (405 nanometers), 18 developed melanoma; only one of 20 control fish kept in subdued yellow light got cancer. It is believed that melanin absorbs light, setting off a chemical reaction that produces compounds damaging to DNA. (See also sunblock; sunburn; sun PROTECTION FACTOR.)

How To Prevent Skin Cancer

How To Prevent Skin Cancer

Complete Guide to Preventing Skin Cancer. We all know enough to fear the name, just as we do the words tumor and malignant. But apart from that, most of us know very little at all about cancer, especially skin cancer in itself. If I were to ask you to tell me about skin cancer right now, what would you say? Apart from the fact that its a cancer on the skin, that is.

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