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Researchers Discover 'Cancer Spreading' Gene

Posted on: Tuesday, 6 January 2009, 14:20 CST

U.S. researchers said on Monday that 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.

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, researchers said.

Dr. Michael Reiss of The Cancer Institute of New Jersey in New Brunswick said 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.

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

Doctors have stressed the importance of stopping cancer’s spread. They say 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.

The researchers used several different approaches to find the gene, which helps tumor cells stick to blood vessels in distant organs.

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.

The team noted that while most normal DNA sequences contain only two copies of a gene, some breast tumors were found with as many as eight copies of this gene segment.

Human breast tumor samples were taken from 250 patients to look for these genetic abnormalities and researchers found that the gene MTDH was overly active or expressed in aggressive tumors.

Kang said this gene exists in every one of our cells.

"Somehow the tumor gains extra copies and overexpresses them. We saw 30 to 40 percent of them overexpressed this gene."

Lab mice were then injected with tumor cells from patients who had this genetic alteration and researchers found the mice formed tumors that were more likely to spread and were also more likely to resist treatment with traditional chemotherapy drugs, such as paclitaxel.

But when they genetically altered these tumors, inhibiting the MTDH gene, the tumor cells were less able to spread and were more vulnerable to chemotherapy.

“We’re hopeful the finding will lead to drugs that not only keep breast cancer from spreading, but also make it more responsive to treatment,” Kang said.

"If we have a drug to inhibit this type of gene, one stone hits two birds."

MTDH may also play a role in other types of cancers, including prostate cancer. "It's likely to be a broad influence gene," he said.

It could also be possible to develop an antibody to neutralize the activity of the gene, he added.

The research has already gained the attention of drug makers. Kang is set to meet with Johnson & Johnson next week.

"I'm quite optimistic we will try to develop a drug as quickly as possible," he said.

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On the Net:

• The Cancer Institute of New Jersey

Source: redOrbit Staff & Wire Reports

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