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Science Behind the Cancer

How does sunlight affect the skin?

So you have most likey heard that exposure to ultraviolet light is the primary reason for the formation of skin cancers. But what exactly is UV light?

By Jonathan S Urie [CC BY-SA 3.0 (], via Wikimedia Commons


According to the World Health Organization, "Ultraviolet (UV) radiation is part of the electromagnetic spectrum emitted by the sun. Whereas UVC rays (wavelengths of 100-280 nm) are absorbed by the atmospheric ozone, most radiation in the UVA range (315-400 nm) and about 10% of the UVB rays (280-315 nm) reach the Earth’s surface. Both UVA and UVB are of major importance to human health.

"Small amounts of UV are essential for the production of vitamin D in people, yet overexposure may result in acute and chronic health effects on the skin, eye and immune system."




"Ultraviolet Radiation." Ultraviolet Radiation and the INTERSUN Programme. World Health Organization. Web. 12 June 2016.



Melanin is what you see when you tan, but it is important to note that this tan is your body's response to skin damage. According to the Skin Cancer Foundation, "In some studies, investigators induc[ed] tanning with topical applications of DNA fragments...The current thinking is that tanning is a biological signal by the skin that reflects the presence of DNA impairment."

UVA: long rays, penetrate glass, levels constant all year, reach deep layers of skin.

UVB: short rays, don’t penetrate glass, levels higher in summer, affect top layers of skin.

Thankfully, the human body does have ways to block the damaging effects of the sun. Melanin, a pigment in the skin, helps to prevent damage from UVB.

Cancer is born when the UV radiation causes a genetic mutation by damaging your DNA. This damaged DNA leads to abnormal cells. These cells have uncontrolled division which generates cancerous growth.


Skin Cancer


  • In 2009, more than 1 million people were diagnosed with skin cancer, making it the most common of all cancers.1-4 More people were diagnosed with skin cancer in 2009 than with breast, prostate, lung, and colon cancer combined.2 About 1 in 5 Americans will develop skin cancer during their lifetime.15

  • One American dies of melanoma almost every hour.2

  • Melanoma is the second most common form of cancer for adolescents and young adults (15-29 years old).16

  • For people born in 2009, 1 in 58 will be diagnosed with melanoma.17—nearly 25 times the rate for people born in 1935.18

The mission of this website is to educate about skin cancer and provide skin protection information in a relevant and interesting manner to 15-29 year-olds.  

Students are Sun Safe

Skin Cancer Institute Logo

​Project SASS

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