The SOX9 protein plays an important role in the increase of protective skin pigmentation after exposure to ultraviolet (UV) radiation, researchers said.

The protein is present in the embryo development and is now found to be important to adult skin cells and can be regulated by UV radiation, according to a study by the National Cancer Institute (NCI) and the National Institutes of Health (NIH).

UV radiation from the sun or other sources, such as tanning parlors, can cause many types of damage to the skin and has been associated with a process that leads to many types of skin cancers. Individuals with lighter skin incur greater damage from UV and thus have a significantly higher risk for skin cancer. Melanin, produced by melanocytes, is a pigment produced in the skin that helps protect cells from cancer-causing UV rays. Melanoma, the most deadly of the skin cancers, is a cancer of melanocytes.

Melanocytes express SOX9 under normal conditions and when exposed to UV radiation, the levels of SOX9 continued to increase up to eight hours after exposure.

Increased pigmentation of the skin from UV was originally thought to help minimize the damage from UV, said NCI Director Dr. John Niederhuber. The research findings now show that SOX9 is the body’s way of protecting itself from UV rays and it gives researchers important insights into the cellular pathways that might contribute to the origins and spread melanoma.

"The most novel part of this study was the fact that we identified a new transcription factor that may be the earliest responder to stimulation of pigmentation such as seen in the tanning reaction following UV exposure," said Vincent Hearing, senior author of the study and chief of the NCI’s Center for Cancer Research’s Pigment Cell Biology Section. "SOX9 is likely one of the first factors that’s activated to start the chain of events that eventually leads to increases in skin pigmentation."

Hearing’s research team is now examining the effect of SOX9 on the proliferation the tumor-promoting properties of melanoma cells to see whether SOX9 could be used to target melanoma via SOX9.

For more information visit www.cancer.gov .