December 1, 2008

Understanding Why Melanoma Survives

Scientists say they have made a critical discovery in understanding what allows the most aggressive and deadly form of skin cancer to survive and proliferate in the body. Their findings could help doctors design new strategies to prevent malignant melanoma.

The process of tanning involves synthesis of the pigment melanin by skin cells called melanocytes, researchers said. That melanin then becomes a natural sunscreen when it spreads to neighboring skin cells, providing some protection against ultraviolet radiation in sunlight.

This triggers a chain of events in the skin cells that leads to the activation of genes that control pigment production. Researchers said the response of a particular protein controlled by a network of these genes to UV radiation in human skin is still not well understood. The protein, PAX3, is essential for melonocyte development, scientists said.

A team led by Dr. Rutao Cui of the Oncology Institute at Loyola University in Chicago identified PAX3 as an important contributor to the UV pigmentation response and to melanoma cell survival and proliferation.

They also discovered that more PAX3 was present in melanomas from sun-exposed skin compared with non-sun-exposed skin.

"This study will provide a rich foundation for further research on skin cancer prevention by enabling us to identify targeted small molecules in the signaling pathways of the UV-induced melanogenic response that are highly likely to induce naturally protective pigmentation," Cui was quoted as saying.

SOURCE: Molecular Cell, Nov. 21, 2008


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