“Morning after” sun cream may prevent skin cancers

The cream uses a bacterial enzyme, T4 endonuclease, to identify, snip away, and repair fused pyrimidine base pairs in DNA, which frequently result from exposure to ultraviolet light. In a preliminary study involving 30 patients with xeroderma pigmentosum, the researchers found that the lotion reduced the incidence of basal cell carcinomas by 30% and of actinic keratoses by 68%, compared with placebo (Lancet 2001;357:926-9).