"Very light skin and a very poor ability to tan correlates with a very high probability of developing cancer," said Fisher, who is chief of the dermatology service at Massachusetts General Hospital in Boston.
So it's possible that darkening the skin's pigmentation might help neutralize the risk associated with genes for light-colored hair and fair skin.
When the researchers applied the enzymes onto mice and samples of human skin in a lab, both the mice and the human skin turned increasingly dark as more enzymes were applied, according to the study published in Cell Reports.
A drug that darkens pigmentation may have uses beyond the theoretical protection against skin cancer, including to cosmetically darken skin among people with other medical conditions, said Dr.
"There is a limited number of drugs available that can effectively elevate pigmentation in a safe way," said Zippin, who was not involved with the new research.