Cancer cells on the move.

A gene recently linked to liver, skin, and pancreatic cancer also lies behind an often deadly form of breast cancer. A new study suggests how that gene causes such aggressive cancer.

Inflammatory breast cancer accounts for about 6 percent of new breast cancer cases in the United States each year. By the time it's diagnosed, the disease has typically spread to other parts of the body.

The protein made by a gene called RhoC helps both normal and cancer cells move, says Kenneth van Golen of the University of Michigan Health System in Ann Arbor. His team exposed skin cells from human breasts to a chemical that attracts cells. Those cells genetically engineered to have extra copies of RhoC moved farther and faster over 3 hours than cells without the extra genes did and were more than five times as likely to burrow into an attractant-laced filter.

Such characteristics might help explain why inflammatory breast cancer cells, which tend to have extra copies of RhoC or mutations in that gene, spread so quickly throughout a woman's body, van Golen says.

The researchers also injected mice with the engineered cells or with cells from a woman's inflammatory breast tumor. Of 20 mice in each group, 5 receiving the cells with extra RhoC and 17 getting tumor cells developed new breast tumors. The difference suggests that RhoC alone doesn't drive inflammatory breast cancer, van Golen reports in the Oct. 15 CANCER RESEARCH. Nevertheless, inhibitors of RhoC may be effective cancer treatments, speculates Richard Hynes of the Massachusetts Institute of Technology.