Gene Quartet May Spread Breast Cancer

Four genes apparently gang up to help breast cancer spread
to the lungs, scientists report in Nature.

Silencing those genes may be a new strategy to stop breast cancer from
spreading (metastasizing), note the researchers.

They included Joan Massague, PhD, of the Howard Hughes Medical Institute and
the Cancer Biology and Genetics Program at New York's Memorial Sloan-Kettering
Cancer Center.

Massague's team studied four genes -- the EREG gene, the Cox-2 gene, and the
MMP1 and MMP2 genes -- in human breast cancer cells injected into mice.

In some of the cancer cells, all four genes were inactive. Those breast
tumors had trouble growing new blood vessels and spreading cancer cells into
the mice's lungs.

In other cancer cells, only one of the four genes was inactive. That didn't
do much to curb breast cancer from spreading to the mice's lungs.

The four genes are most effective when they work together, the researchers
conclude.

New Treatment?

Additionally, the researchers studied another set of mice injected with
human breast cancer cells.

The scientists treated some of the mice with three drugs -- the cancer drug
Erbitux, the anti-inflammatory drug Celebrex, and an experimental
anti-inflammatory drug -- that together target all four genes.

For comparison, other mice got no drug treatments.

The drug combinations hampered breast cancer from spreading to the mice's
lungs, the study shows.

"This really nailed the case that if we can inactivate these genes in
concert, it will affect metastasis," Massague says in a Howard Hughes
Medical Institute news release.

Next Steps

Massague says clinical trials of the drug combination are being
discussed.

However, Massague points out that "there are already treatments to
diminish the chance of metastasis in breast cancer, so such trials would have
to be designed very carefully to understand how and whether the new drug
combination would be of additional benefit."

Further studies should be done to see whether the gene quartet affects
breast cancer's spread to other organs, writes Gerhard Christofori, PhD, in an
editorial in Nature.

Christofori is a biochemistry professor in the clinical biological sciences
department at Switzerland's University of Basel.

By Miranda Hitti
Reviewed by Louise Chang
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