Courtesy, TheGuardian.com 

With summer here, it is important to be sun-safe, protecting your skin from harmful, damaging rays.

 A study in mice finds that SPF 50 cream only reduces DNA damage, increasing length of time before melanoma develops.

High-factor sun cream cannot be relied on to protect against the deadliest form of skin cancer, research has suggested.

The study by Cancer Research UK found that while high-factor cream can reduce DNA damage caused by the sun and slow the onset of malignant melanoma, it does not give complete protection.

It proves that public health campaigns are right to promote a combination of protection methods such as hats and shade alongside sun cream, scientists said.

During the study, mice who were predisposed to melanoma took about 30% longer to develop cancer when coated in SPF 50 sun cream than when they were not. The research, published in the journal Nature, revealed that UV light directly damages DNA in the skin's pigment cells, which increases the chance of developing the disease.

Scientists discovered that UV light also causes faults in the gene that helps to protect against sun damage.

Prof Richard Marais, author of the study and a scientist with Cancer Research based at the University of Manchester, 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.

"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."

Dr Julie Sharp, head of health information at Cancer Research UK, said people exposed to sunlight must wear a cream with good UVA protection.

"We've known for some time that sunscreen, when applied properly, can help protect our skin from the harmful effects of the sun's rays," she said. "But people tend to think they are invincible once they have put it on and end up spending longer out in the sun, increasing their overall exposure to UV rays.

"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.

"When the sun is strong, pop on a T-shirt, spend some time in the shade and use a sunscreen with at least SPF 15 and good UVA protection."

Malignant melanoma is the fifth most common cancer in the UK, with more than 13,000 people diagnosed with the disease every year. Cancer Research UK said the number of cases is increasing, which has led it to make skin cancer a key focus of research.