Moisturizers Up Skin Cancer in Mice

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Moisturizers Up Skin Cancer in Mice

4 Commonly Used Moisturizing Creams Promote Tumors in UV-Exposed Mice

By Daniel J. DeNoon

WebMD Health News

Reviewed by Louise Chang, MD

 

Aug. 14, 2008 -- Four commonly used moisturizers promoted skin cancers

in mouse studies.

 

Mice are not men. But the unexpected finding suggests that these --

and perhaps other products -- may not be as safe as they're thought to

be.

 

The moisturizers tested in the study were Dermabase, Dermovan (a

wholesale-only product discontinued in 2006), Eucerin Original

Moisturizing Cream, and Vanicream.

 

In a mouse model of sun-related skin cancer, frequent application of

each product resulted in more skin tumors and faster tumor growth,

says study leader Allan H. Conney, PhD, director of the Susan Lehman

Cullman Laboratory for Cancer Research and professor in the school of

pharmacy at Rutgers University in Piscataway, N.J.

 

" This was unexpected. We really did not expect to see the

tumor-promoting activity of these creams, " Conney tells WebMD.

 

In fact, Conney and colleagues were getting ready to use one of these

moisturizers -- Dermabase -- in human clinical trials of topical

caffeine, which prevents skin cancer in animal studies.

 

" We thought it would be prudent to test Dermabase by itself to see if

it had tumor-promoting activity, " Conney says. " We did not think it

would. But lo and behold, to our surprise we got an increased rate of

skin cancer. "

 

This led to new tests of Dermabase and the three other moisturizers,

which the Conney team hoped to use in their human study. For these new

animal studies, the researchers used hairless mice irradiated with

ultraviolet light twice a week for 20 weeks. With no further

irradiation, such mice eventually develop skin cancer -- very much

like humans overexposed to sunlight early in life.

 

Five days a week, for 17 weeks, the researchers rubbed moisturizer

into the animals' skin. The result:

 

* Dermabase increased the total number of tumors by 69%.

* Dermovan increased the total number of tumors by 95%.

* Eucerin increased the total number of tumors by 24%.

* Vanicream increased the total number of tumors by 58%.

 

" The multimillion-dollar question is, what about humans? " Conney asks.

" The answer is, we don't know. Our study raises a red flag and points

out the need for epidemiologists to take a look at people who use

moisturizing creams. And the companies that market these products

should take a look at animal models and see if their products promote

tumors. "

Testing Moisturizers for Safety

 

Dermatologist Keyvan Nouri, MD, director of dermatologic surgery at

the University of Miami Miller School of Medicine and author of the

best-selling book Skin Cancer, agrees that companies that make

moisturizers should test their products.

 

" This study could definitely be a warning to alert these companies to

consider testing moisturizing creams with some sort of assay, " Nouri

tells WebMD. " These creams need to be tested first before they come to

market. "

 

Moisturizers are classified as cosmetics by the FDA, which does not

require that they undergo the same safety and efficacy tests required

for drugs

 

The moisturizers did not cause cancer in the mice. That came from

their early-life radiation exposure. But the creams did make skin

cancers grow faster and more readily.

 

Nouri notes that the radiation damaged the skin of the mice before the

moisturizing creams were applied. That, he says, might account for the

moisturizers' unusual tumor-promoting effect.

 

However, he notes that the skin cancers are becoming much more common in humans.

 

" There are over a million cases a year, " he says. " It is by far the

most common cancer we deal with. Skin cancers account for more than

half of all cancers combined. But most skin cancers are totally

curable. "

 

What is it about the moisturizers that might promote cancer?

 

The Conney team asked Johnson & Johnson to make them a " custom blend "

moisturizer without two ingredients previously linked to skin

irritation (sodium lauryl sulfate) and tumor promotion (mineral oil).

The custom blend (on which Rutgers University and Johnson & Johnson

hold a patent) did not promote skin cancer.

 

But not all of the products tested use these ingredients, so exactly

what -- if anything -- might be linked to cancer isn't known. And it's

certainly clear that mouse and human skin are very different.

Moisturizers Still Necessary

 

Nouri warns consumers not to stop using moisturizers.

 

" As we get older, our skin gets drier, " he says. " We need to

moisturize, otherwise our skin gets dry and we get eczema, dermatitis,

rashes, and so on. It is too soon to say from this study people should

stop moisturizing. "

 

Eucerin is made by Beiersdorf Inc.

 

" We have just learned about this study and are currently reviewing it

to understand the findings, " Beiersdorf says in a statement to WebMD.

" Eucerin Original Creme has been on the market for more than 100 years

and is a highly respected, dermatologist-recommended brand. It has

been widely used by both individuals with normal skin and those with

diseased skin under the care of physicians, and no incidents of this

nature have ever been reported. "

 

Vanicream is made by Pharmaceutical Specialties Inc. In a statement to

WebMD, PSI President Conrad O. Thompson, RPh, says there is nothing in

the Conney study to indicate any need for change in current

recommendations for use of Vanicream.

 

" Treatment with Vanicream Skin Cream clearly did not increase the

proportion of animals that developed tumors, " Thompson notes.

 

Dermovan, a wholesale-only product used as a base to which other

ingredients are added by compounding pharmacists, was made by

Healthpoint Ltd. until the product was discontinued in 2006.

 

" The product has been around for 50 years, and has no safety issues

related to it, " Healthpoint spokesman Mark Mitchell tells WebMD.

 

Dermabase maker Paddock Laboratories Inc. did not respond to WebMD's

request for comment.

 

The Conney study appears in the Aug. 14 advance online issue of the

Journal of Investigative Dermatology.

 

http://www.webmd.com/melanoma-skin-cancer/news/20080814/moisturizers-up-skin-can\

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