[Joe]

HOUSTON - Researchers at The University of Texas M. D. Anderson Cancer Center have solved the mystery of why an aggressive form of HER2-positive breast cancer travels readily to a few key organs - lungs, liver and bone -where it then establishes new tumors. They say this finding may lead to strategies to block that deadly spread.

The study, published in the November issue of Cancer Cell, describes a lethal attraction between signals found on HER2-positive breast cancer cells and those on the surface of the organs -a magnetism that explains why this form of breast cancer, which affects up to 30 percent of patients, can be so invasive. The vast majority of women who die from HER2-positive breast cancer had developed secondary tumors in their lung, liver and bones.
"It has always been a puzzle as to why, when HER2-positive cancer cells circulate throughout the body looking for a new home, they preferentially travel to these organs," says the study's lead author, Mien-Chie Hung, Ph.D., a professor and chair of the Department of Molecular & Cellular Oncology. "We now have explained it biochemically, and hope that this leads to strategies that prevent such metastasis."
Their discovery focuses on the relationship between HER2 and chemokine receptor proteins on breast cancer cells. Chemokines are a large family of proteins primarily known to speed inflammatory responses by drawing them to circulating white blood cells that have a corresponding chemokine receptor. Researchers have found that some diseases, including HIV and cancer, use this same chemical attraction to invade the body.
Although scientists already had discovered that the chemokine receptor CXCR4 was involved in the movement of certain forms of breast cancer to target organs, they did not know how CXCR4 did that for HER2-postive breast cancer until now.
The M. D. Anderson team specifically found breast cancer that overexpress HER2 proteins also ramp up production


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Joe