SATURDAY, Oct. 6, 2001 (HealthDayNews) -- We've all been guilty of it and we've all regretted it later -- spending too much time in the sun only to return home with an angry, red sunburn.
Until now, there hasn't been much you could do to repair the damage -- and the threat of skin cancer.
But in what some health experts are calling a potentially major advance in the fight to prevent skin cancer, researchers are working on an experimental cream that appears to fix the cellular damage caused by overexposure to the sun.
Earlier research showed that the cream helped to prevent skin cancer in people with a rare disorder called xeroderma pigmentosum, or XP. People with XP are so sensitive to sunlight that they have to spend their lives indoors with the shades drawn. Their skin can blister after only a few minutes of sun exposure, and they get skin cancer at 1,000 times the average rate.
Results of the clinical trials involving the XP patients were published recently in the journal The Lancet. Those who used the cream for a year had a 68 percent reduction in actinic keratoses, which can become squamous cell skin cancer, and a 30 percent reduction in basal cell cancer.
The cream, called Dimericine, contains an enzyme that helps repair DNA, the genetic building block for all cells, says Daniel Yarosh, a molecular biologist who developed the cream.
Skin cancer is caused by mutations to DNA from repeated exposure to the sun's ultraviolet rays. When rubbed on the skin, the enzyme in the cream penetrates the skin's cells and goes to work.
"The enzyme speeds up the rate of repair to the damage in the skin, and in that way can reduce the incidence of skin cancer," says Yarosh, president of Applied Genetics, Inc. Dermatics, in Freeport, N.Y.
So what does this mean for the average sunbather, gardener, tennis player or golfer?
Dr. David Leffell, a professor of dermatology and surgery at Yale University School of Medicine, calls the cream "the biggest advance since sunscreens."
Although it's too soon to say for certain that the cream that works on XP patients will help to prevent skin cancer in others, it looks extremely promising, Leffell says. The DNA mutations that occur in XP skin-cancer patients are largely the same as in any other case of skin cancer.
"This is the first time I know of anything that has been able to repair a mutation caused by an environmental carcinogen, namely the sun," Leffell says.
This fall, independent researchers plan to test Dimericine in three sunny cities: Los Angeles, San Diego and Jacksonville, Fla. They will test the product on 600 people who have had one skin cancer lesion removed and are at high risk for more.
Dimericine shows promise in preventing basal cell or squamous cell skin cancer, the most common skin cancers among white Americans. The cream hasn't been studied yet for use in preventing melanoma, the deadliest skin cancer.
More than 1.3 million Americans will be diagnosed with basal cell or squamous cell cancer this year. When caught early, these types of cancer are highly treatable. The cancer can usually be removed in a doctor's office.
About 51,000 Americans will develop melanoma this year, and about 10,000 people will die from skin cancer this year -- mostly from melanoma.
The biggest hurdle to developing the cream, Yarosh says, was finding a way to get the healing enzyme to penetrate the skin. Most creams remain on the outer layer of dead skin cells and are sloughed off when bathing. Yarosh says he developed a liposome -- a microscopic sac of fat molecules -- that can deliver the enzyme deep into skin cells.
"When we started our research in the late '80s, dermatology taught that the skin was impenetrable," Yarosh says. "Our technology is based on the invention of liposomes that can penetrate the outer layer of skin cells."
Despite Dimericine's potential, the best methods to prevent skin cancer remain avoiding overexposure to the sun, wearing protective clothing and using sunscreen liberally, Leffell says.
The cream has not been shown to cure skin cancer that has already developed. And it won't do anything for wrinkles.
"The main focus is preventative," Leffell says, likening it to a "morning-after pill."
What to Do: For more information on protecting yourself and your children from ultraviolet rays, check out the American Academy of Dermatology. And see this American Cancer Society Web site on nonmelanoma skin cancer.
