Scientists find a gene that makes cancer spread

By Julie Steenhuysen

CHICAGO (Reuters) - A single gene appears to play a crucial role in deadly breast cancers, increasing the chances the cancer will spread and making it resistant to chemotherapy, U.S. researchers said on Monday.

They found people with aggressive breast cancers have abnormal genetic alterations in a gene called MTDH, and drugs that block the gene could keep local tumors from metastasizing or spreading, increasing a woman's chances for survival.

"Not only has a new metastasis gene been identified, but this also is one of a few such genes for which the exact mode of action has been elucidated," said Dr. Michael Reiss of The Cancer Institute of New Jersey in New Brunswick, whose study appears in the journal Cancer Cell.

"That gives us a real shot at developing a drug that will inhibit metastasis," he said in a statement.

Stopping cancer's spread is important -- while more than 98 percent of patients with breast cancer that has not spread live five years or more, only 27 percent of patients whose cancer has spread to other organs survive.

Reiss and Yibin Kang of Princeton University used several different research approaches to find the gene, which helps tumor cells stick to blood vessels in distant organs.

To get them in the right general area, they used big computer databases of breast tumors and found that a small segment of human chromosome 8 was repeated many times in people with aggressive breast tumors.

While most normal DNA sequences contain only two copies of a gene, they found some breast tumors had as many as eight copies of this gene segment.