What is Ultraviolet Radiation? Ultraviolet (UV) radiation is a type of energy produced by the sun and is the main environmental and modifiable cause of melanoma and other skin cancers. There are three types of UV radiation. UVC is the most dangerous type of UV radiation, but fortunately, the sun’s UVC is absorbed by our atmosphere before it reaches the earth’s surface. UVB penetrates the top layer of the skin and is the primary cause of sunburns. UVB is the main cause of melanoma, as well as basal cell and squamous cell skin cancers. UVA radiation penetrates more deeply into the skin, causes photoaging (wrinkling and leathering), and increases oxidative stress, which indirectly causes mutations—increasing your risk for developing melanoma and other skin cancers.
How are Tanning and Burning Related to UV Damage? When ultraviolet (UV) rays of the sun penetrate your skin’s top two layers—the epidermis and dermis— the UV rays cause DNA damage to the cells in both layers. Melanocytes live at the basal layer of your skin, the deepest part of the epidermis, and when they get hit with UV light, your melanocytes respond by making little melanin packets—little umbrellas—and send those packets out to protect other skin cells. The melanin serves as a shield for your skin, trying to help it avoid further damage. Your skin produces melanin (and darkens, or “tans”) as a means of self-protection: Your skin tans to protect itself from burning. You burn when your skin cannot produce enough melanin to prevent UV rays from injuring the skin’s surface and capillaries. The amount of damage has exceeded what the cells can take. Every burn increases your risk of developing melanoma. In fact, your risk for melanoma doubles if you’ve had more than five sunburns, and just one blistering sunburn in childhood or adolescence more than doubles your chances of developing melanoma later in life. The darkening of your skin—whether tanned or burned—is objective evidence of DNA damage. The more you damage your DNA, the greater your risk of developing melanoma. page 3
