Small melanin particles cause skin cancer
Mar 24, 1999
Melanoma skin cancer is one of the most common forms of cancer contracted today. Although Ultraviolet B (UVB) radiation is known to cause the disease, little is understood of the effects of Ultraviolet A (UVA) radiation. John Simon of Duke University in the US has measured the absorption and emission of light from different sizes of natural and synthetic eumelanins - brown-black pigments on the surface of the skin - that are the main UVA receptors. He found that small particles of eumelanin (below 100 molecular weight) are more susceptible to absorbing UVA radiation than large particles.
The radiation causes the eumelanin to generate large quantities of free oxygen radicals, which in turn damage cell DNA and hence may lead to cancer. His research was reported yesterday at the annual American Physical Society meeting in Atlanta, Georgia.