An unexpected immune protein exacerbates cancer due to sun exposure, scientists have discovered.
Their study suggests that drugs blocking the protein might halt tumor growth in skin cancer patients.
Cutaneous melanoma, an aggressive form of skin cancer, appears to be on the rise. And mortality rates from this difficult-to-treat disease are some of the highest in cancer.
In order to discover new ways of treating melanoma, Edward De Fabo, a research professor of in the department of Microbiology, Immunology, and Tropical Medicine at George Washington University Medical Center in Washington, D.C. and a co-corresponding author on the current paper, has been examining the pathway between ultraviolet (UV) rays and melanoma for over a decade.
"We ultimately want to figure out what goes wrong so that we can fix it," De Fabo says.
In 2004, he and his collaborators confirmed suspicions that UV-B radiation, as opposed to UV-A, triggered melanoma.
And in the current study, they find that UV-B causes white blood cells called macrophages to migrate higher in the skin of mice and release an immune protein, interferon-y.
Instead of protecting the body like most interferon proteins do, interferon-y allowed tumors to grow by preventing the body's natural immune response.
"We didn't expect to see interferon-y aiding the tumor, instead of killing cancerous cells," De Fabo says.
The study has been reported in the January 27th issue of Nature.