New blood test

A blood test can detect over-expression of a gene in circulating cells associated with breast cancer.

Dr. Jonathan Uhr and his colleagues at UT Southwestern Medical Center at Dallas have developed a blood test that can detect over-expression of a gene found in circulating cells associated with breast cancer.

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The blood test could be used as a standard operating procedure to monitor genetic changes for which a treatment is available, the researchers claimed.

"Cancer is a moving target, and the oncologist has to know which bullet to put in his gun. Obtaining repeated blood samples is a safe and routine procedure, and this test can help the oncologist determine whether a new genetic change has become dominant and calls for a specific treatment for that change," said Uhr, senior author of the study.

The researchers developed a blood test to optimize the detection and characterization of circulating cancer cells shed from a primary tumor. Matching the cells' genetic abnormalities with the parent tumor does this. The test can detect one circulating tumour cell in 10 million white blood cells.

The research augments previous work by UT Southwestern researchers to determine if patients whose primary tumour did not have amplification of the gene HER-2 could acquire amplification if the tumour recurred and progressed.

Uhr said that in a patient whose primary tumour is classified as HER-2 gene non-amplified, a minute number of tumour cells actually may be HER-2 amplified. With time and selective pressures, this small population expands and becomes the predominant one.

"The implications of tumour evolution over the course of treatment are significant. A better understanding of this process will not only allow us to use available drugs in a more individualized fashion but also may point to new therapeutic approaches," said Debasish Tripathy, professor of internal medicine and contributing author of the study.