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Blood Test May Prove New Way to Detect Breast Cancer Gene - 2004-06-10

Some researchers are hailing the discovery of a blood test that could lead to the treatment of breast cancers that may be missed by doctors. The test looks for a gene that becomes more active as the cancer progresses.

When a primary breast tumor is removed, it is tested for overactivity of HER-2, a gene that is involved in the growth of many breast cancers. About 80 percent of these tumors test positive. The patients are then treated with a drug called Herceptin that's often effective in fighting the cancer.

But researchers believe HER-2 sometimes lurks in patients' bodies, undetected by conventional testing. They say as a result, some women who could benefit from Herceptin never receive it.

Cancer researcher Jonathan Uhr and colleagues report on the development of a blood test that found the presence of overactive copies of HER-2 found in women who did not test positive at the time their tumors were removed.

Dr. Uhr says he's excited about the results.

"Yes, I feel very strongly about them because if these preliminary studies we've done are confirmed by further studies with more patients and further experiments, that would mean that patients at the present time are not getting optimal treatment," he said.

Dr. Uhr of the of the University of Texas Southwestern said that researchers tested the blood of 24 patients who were not treated with Herceptin after surgery. The test revealed HER-2 in 9 of the patients. They treated four of the women with Herceptin. Three of the patients responded positively. The fourth had an almost complete remission.

The findings, says Dr. Uhr, go against the mainstream view about cancer, that if a tumor tests negative for a cancer gene, that gene does not exist in the body.

"I think it's always challenging when you have a study which contradicts current dogma," he explained.

He added that his group's study indicates that cancer cells circulating in the blood can develop HER-2 gene overactivity as the disease progresses. Researchers hope further studies prove the value of the blood test in the diagnosis and treatment of breast cancer.

The study on the HER-2 gene was published in Proceedings of the National Academy of Sciences.