SHIELDING the skin from the sun rays that cause burning may provide little protection against cancer, a new study suggests today.
Scientists have discovered that UVA rays, which do not burn, are potentially far more damaging to skin cell DNA than was previously realised.
UVA, responsible for the ageing effects of the sun, penetrates deeper than the shorter wavelength UVB rays that cause sunburn.
Because it is less strongly absorbed by DNA than UVB, it has been considered less of a cancer risk.
But the research from the university of Sydney, Australia, has found mutation "fingerprints" in skin tumours that show this belief is mistaken.
The changes, bearing the hallmark of UVA damage, were found in the deep basal keratinocyte cell layer.
Developing skin cells migrating out from this region might be highly vulnerable to cancer, researchers believe.
The scientists said:
"The importance of protecting the population not just from UVB but also from UVA irradiation has profound implications on public health worldwide."