It looks like a major skin disaster, but a sunburn may be the body’s attempt at a defense mechanism against certain types of skin cancer, according to authors of a recent study at the Yale University School of Medicine. “The peeling of a sunburn is the result of cells seriously damaged by ultraviolet light,’’ explains study coauthor David J. Leffell, M.D., chief of dermatologie surgery at Yale. When ultraviolet light strikes normal skin cells, it can either terminally damage or merely mutate the DNA in the cells. When the cell DNA is terminally damaged, it activates the p53 gene, which in turn directs skin cells to die. If the radiation causes only a mutation of the p53 gene, the skin cells do not die but keep on dividing and proliferating abnormally in spite of the impaired genetic material.
“These mutated cells have lost their cancer-controlling p53 mechanism,” says Dr. Leffell. “Without this gene that tells cells when to die, these cells keep on multiplying. It’s this uncontrolled cell growth technically the definition of cancer that seems to lay the foundation for premalignant and eventually malignant lesions.” Sunburn is still a sign that you have seriously damaged your skin, says Dr. Leffell. The same holds true for tanning. While the exact mechanism is not known, a tan is another form of damage control. Basically, the brown pigment melanin is produced to physically shield the cell’s nucleus, protecting the DNA. The catch is that tanning is not triggered until sun exposure has occurred and after damage has been done. Is there such a thing as a healthy tan? Not on your life.