The development of a noninvasive test capable of spotting a single cancer cell in a blood sample may have received a boost today when Harvard researchers announced they were partnering with Johnson & Johnson on a five-year, $30 million agreement to bring the technology to market.
An article published in the Boston Globe today explains how the experimental test works:
To detect the extremely rare cells, the new technology uses minuscule channels carved into a silicon chip, coated with a special glue-like substance. When the blood filters through the channels, [Daniel Haber, MD, PhD, director of the Massachusetts General Hospital Cancer Center] said, the technology is able to pick up, on average, about 10 cancer cells per milliliter of blood in patients with metastatic cancer, disease that has spread from a primary tumor to other parts of the body.
Curious about the potential of the test, I contacted Stanford pathologist Edgar Engleman, MD. He said:
Overall, the test is very interesting and conceptually it's something that is on the horizon. The test is very similar, in principal, to the blood test administered to pregnant women for determining if a fetus is at risk for certain birth defects. Since it's the same principle, it makes sense that a blood test could be used to detect cancer cells.
A test that can detect one, or very few, cancer cells in the circulation is very appealing because theoretically it could be used to determine if someone has cancer, if a patient has been effectively treated or if they are at risk of metastasizing. But this announcement sounds a little premature. Typically, when we see medical announcements it's on the basis of some presentation of data and this announcement is about subjecting the test to clinical trials.
A number of questions remain. For example, how sensitive is the test? How reliable is the data? How useful is it? There will be a need for extensive studies to determine how useful this test is.
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