Increased levels of a cell chemical receptor called CXCR4 is needed for the spread of certain hereditary breast cancers, researchers report in the journal Cancer Cell.

Why these “HER2-positive” cancers preferentially travel to organs such as the lung, liver and bones has “always been a puzzle,” senior author Dr. Mien-Chie Hung said in a statement. “We have now explained it biochemically, and hope this leads to strategies that prevent such metastasis.”

Hung, from M. D. Anderson Cancer Center in Houston, and colleagues established that CXCR4 plays an important role in the spread of hereditary breast cancer. Levels of this receptor were much higher in HER2-positive cancer cells than in other cells. Moreover, as levels of the HER2 protein increased, so did CXCR4 levels.

CXCR4 latches on to chemical signals that are emitted by other cells. “HER2 turns on and then magnifies the ability of (breast) cancer cells to zero in on organs” that release the chemical that binds to CXCR4, Hung explained.

Because CXCR4 levels have been linked to breast cancer survival, the new findings “will have important clinical implications,” the authors write.

SOURCE: Cancer Cell, November 2004.