Sunscreen alone does not provide complete protection against skin cancer

As exposure to ultraviolet light from the sun is a major risk factor for melanoma, a serious form of skin cancer, wearing sunscreen to protect against the damage that sun can cause to the skin is extremely important. However, recent research carried out by the University of Manchester's Cancer Research UK Institute and the Institute of Cancer Research,suggests that sunscreen alone is not enough to protect against the disease.

To reach their findings, the research team analysed the effects of UV light on 2-month-old mice with an abnormal BRAF gene, which is known to increase the risk of melanoma.

The researchers found that on unprotected skin, UV light directly damages the DNA of pigment cells in the skin, which raises the risk of melanoma. Specifically, the team discovered that exposure to UV light leads to abnormalities in a gene called p53, which usually works to prevent DNA damage from UV radiation.

After applying sunscreen to the skin of the mice, the team found it significantly reduced the level of DNA damage caused by UV radiation, which slowed development of melanoma. However, the researchers also found that sunscreen failed to offer total protection from UV light and that the radiation was still able to cause abnormalities in the p53 gene, just at a lower rate.

Commenting on the findings, study author Professor Richard Marais, a scientist at Cancer Research UK, said:

"UV light has long been known to cause melanoma skin cancer, but exactly how this happens has not been clear. These studies allow us to begin to understand how UV light causes melanoma.

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."

Dr. Julie Sharp, head of health information at Cancer Research UK, notes that although sunscreen if applied properly can protect against UV radiation, people tend to assume that they are safe from harm once they have put it on and spend longer in the sun. As a result, overall exposure to UV light is increased.

She comments: "This research adds important evidence showing that sunscreen has a role, but that you shouldn't just rely on this to protect your skin. It's essential to get into good sun safety habits, whether at home or abroad, and take care not to burn - sunburn is a clear sign that the DNA in your skin cells has been damaged and, over time, this can lead to skin cancer."

The study is published in the journal Nature.

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