Sunscreens do Not Offer Complete Protection Against Melanoma

A new study states that sunscreens do not offer complete protection against melanoma.

One of the most dangerous forms of skin cancer - melanoma - begins in the cells and produces melanin pigment. It develops from moles. Melanoma kills an estimated 8,790 people in the U.S. annually. The American Cancer Society estimates that at present, about 120,000 new cases of melanoma are diagnosed in the U.S. every year.

Researchers at the Neurosciences Institute, Joint Center of the University Miguel Hernández (UMH) based their finding on the study conducted on mice. They demonstrated that sunscreen, even with sun protection factor (SPF) 50, fails to offer complete protection against the development of melanoma. They claim that sunscreen offers protection only against the immediate radiation damage, which includes sunburns. But surprisingly, the radiation still penetrates and damages the DNA and causes cancer.

Using genetically-modified mice that were susceptible to melanoma, they discovered that the UV light triggers mutations in the DNA of melanocytes in a particular gene called p53.

P53 is a gene that is known as the protector of the genome as it is the key in identifying and repairing damage that accumulates in cells that is produced by UV light and is a barrier against cancer.

"UV light targets the very genes protecting us from its own damaging effects, showing how dangerous this cancer-causing agent is. Very importantly, this study provides proof that sunscreen does not offer complete protection from the damaging effects of UV light," said Professor Richard Marais, study author and Cancer Research UK scientist, based at the University of Manchester. "This work highlights the importance of combining sunscreen with other strategies to protect our skin, including wearing hats and loose fitting clothing, and seeking shade when the sun is at its strongest."

Sunscreen lowered the DNA damage and delayed the development of the skin cancer, but could not protect p53 gene against the harms that is caused by UV light.

"Several epidemiological studies have shown an association between sun exposure and the increased risk of melanoma. However, the molecular mechanism that causes this to happen was not clear," researchers explain.

The finding was documented in Nature.