Moisturizers increase skin cancer in UV-radiation treated mice

Several common moisturizing creams can increase the formation of nonmelanoma skin tumours when applied to UV-radiation treated mice, according to research published online this week in the Journal of Investigative Dermatology.  Mouse skin is quite different from human skin, but the research could help to explain the incidence of some types of skin cancer in patients.

Allan Conney and colleagues from the Susan Lehman Cullman Laboratory for Cancer Research, University of New Jersey, USA, used a hairless, albino mouse model for sunlight-induced non-melanoma skin cancer in humans. They exposed the mice to UV radiation to mimic exposure to the sun and then, after stopping UV treatment, applied 4 different brands of moisturizers to the animals.

Mice treated with each of the four brands had an increased rate of tumour formation, in non-melanoma skin cancer, the least aggressive type. There were also more tumours per animal than in UV-treated mice that were not moisturized.

The team honed in on several ingredients that they believed might enhance tumourigenisis in the skin.  A new moisturizer prepared without these ingredients did not have the same effect of increasing the rate of skin cancer in the UV-exposed mice.

Though the research may initially appear alarming, the authors indicate that the significance of these findings has not been established in humans, a sentiment echoed by former Cancer Research UK head Prof Gordon McVie:

“If the animals were given daily moisturizing creams or ointments after the end of ultraviolet light exposure, more got skin cancers. This has no relevance to causation of human skin cancer, and does not prove in any way whatever that moisturizing creams are cancer-causing in humans. Many more studies now require to be done to follow up this unplanned and inexplicable test result”

Article: Tumorigenic Effect of Some Commonly Used Moisturizing Creams when Applied Topically to UVB-Pretreated High-Risk Mice

Authors: Yao-Ping Lu, You-Rong Lou, Jian-Guo Xie, Qingyun Peng, Weichung J. Shih, Yong Lin and Allan H. Conney

DOI:10.1038/jid.2008.241