Finding Cancer in a Drop of Blood
It hardly seems possible that a single drop of blood will give enough information to diagnose dread diseases such as cancer. Until now, a blood test to determine a patient's cancer risk took several vials of blood and hours or days to analyze, and cost about $500.
But a new method promises a test that would take about 10 minutes and could cost as little as a nickel.
The invention comes from chemist James Heath at the California Institute of Technology and Leroy Hood of the Institute for Systems Biology in Seattle, a pioneering inventor of gene sequencing technologies.
Hood says that this technology is a step forward for a new paradigm of health care that he has long advocated, a form of personalized medicine he calls the "4 P's"-predictive, preventive, personalized and participatory medicine.
"To make this a reality," Hood says of bespoke medicine, "we need to develop new technologies like this: to provide data on individuals that is cheap, specific and informative."
These scientists have founded a company, Integrated Diagnostics, to produce and sell their new blood-drop method. "This company is going to change medicine," says Hood, a scientific co-founder of the biotech giant Amgen and a cofounder of Applied Biosystems and several other companies.
The breakthrough uses an "integrated blood barcode chip" designed to separate out proteins from a patient's blood, and to run them through tiny channels coated with strips of DNA bound to antibodies that capture the proteins the researchers are looking for. The targeted proteins are then coated with a material that lights up under a fluorescent microscope.
In the current experiment, the researchers were looking for free-floating tumor cells that can sometimes foretell the future advent of cancer.
This device is many times more efficient and faster than the traditional methods, which use centrifuges to separate proteins from blood serum and then employ a tedious process of chemical extraction that sometimes takes long enough that the proteins are in danger of degrading.
With the new tool a patient's finger is pricked as in a diabetes blood glucose test, and the blood applied immediately to the analysis. "Patients will be able to monitor themselves several times a day like a diabetic taking blood samples," says Hood.
Hood's vision is to create a raft of tests with the precision to diagnose a number of emerging diseases by detecting the unique proteins that all the body's major organs deposit into the blood. "We're developing a strategy to identify blood proteins that are organ-specific," says Hood. Next up are proteins for the brain and then liver.
The new tests should allow physicians to match patients with specific forms of, say, colon cancer, which could suggest individualized strategies for treatment.
Convincing tradition-bound medicine to think this way-to look for dread diseases in advance rather than react to them after they are manifest-is a gargantuan task. "I think it's going to happen, but only if we have the tools that make it inevitable," says Hood.
One drawback right now is that the fluorescent microscopes are expensive and bulky, and would not work in small clinics or in homes. But this issue is likely to be worked out.
"These devices should lead to a decrease in cost and an incredible benefit to patients," pathologist Emil Kartalov of the University of Southern California's Keck School of Medicine told Technology Review. Kartalov developed some of the blood separation technologies used for the chip, but is not collaborating with Hood and Heath.
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