University of Pittsburgh

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Breakthroughs in the Making

Another Virus-Cancer Link

Written by Ezra Christopher





Pitt researchers are learning more about a virus they discovered last year. Merkel cell polyomavirus (MCV) is the likely cause of a rare but aggressive and deadly skin cancer found in about 80 percent of Merkel cell tumors, says Patrick Moore, professor of microbiology and molecular genetics in Pitt’s School of Medicine. Previously, it wasn’t clear whether the virus actually caused the cancer or just coexisted with already cancerous cells. Researchers, led by Moore and his wife, Yuan Chang, a Pitt professor of pathology, have now confirmed that MCV appears to cause the cancer, as they reported recently in the Proceedings of the National Academy of Sciences.

“MCV infects normal cells before they turn into cancer cells,” says Moore, who also is director of the University of Pittsburgh Cancer Institute’s Molecular Virology Program. It seems that MCV is harmless in a healthy cell until the virus mutates and causes the cell to multiply abnormally, creating a cancerous tumor. “It looks very much like MCV is the culprit that causes the disease,” he adds.

Only seven viruses are known to cause human cancers—and two of them were found by Chang and Moore. In 2003, they shared the prestigious Charles S. Mott Prize for identifying KSHV, a herpes virus, as the cause of Kaposi’s sarcoma, the leading AIDS malignancy.

In January 2008, Moore and Chang, who codirect their lab, reported their initial identification of the Merkel cell virus in Science. At the time, they noted that although up to 16 percent of the population carries MCV, very few will develop cancer.

There is no current treatment for MCV infection, but identifying the source and understanding how it triggers disease could lead to future treatments.