'Lab on a Chip' Might Speed Breast Cancer Monitoring

WEDNESDAY Oct. 7, 2009 -- A pocket-size device under development could soon help monitor how well breast cancer treatments are working and help assess breast cancer risk by measuring levels of the hormone estrogen.

''We've developed a 'lab on a chip,' which is useful for making quantitative measurements of estrogen in samples of blood or tissue," said Aaron Wheeler, the Canada research chair of bioanalytical chemistry at the University of Toronto and a co-author of a report on the device in the Oct. 7 issue of Science Translational Medicine.

The new device relies on a method called digital microfluidics. The technique is being used to analyze hormones found in tiny samples of blood, serum and breast cancer tissue.

Instead of moving electrons across tiny wires, it electronically manipulates minute droplets of fluid on the surface of a microchip, integrating many different lab functions so fewer are needed, Wheeler explained during a teleconference briefing Oct. 6. Hormones are extracted, purified and analyzed. And it's all done on a device that can fit on the palm of the hand, he said.

The "lab on a chip" technique, already under study in other areas, takes raw, unprocessed tissue and delivers results rapidly, Wheeler said. Estrogen can be measured in minutes.

It also requires much tinier samples than those needed by conventional methods, said Dr. Noha Mousa, also a co-author of the report, who is working on her Ph.D. in medicine at the University of Toronto. "This is 1,000 times smaller than the tissue samples required" by other methods, she said.

For their report, the technique was tested on breast tissue from two postmenopausal breast cancer patients.

Estrogen concentrations are not routinely measured because doing so with conventional methods requires large samples, the researchers noted in their report. But they said that a simpler measuring technique would, for instance, allow doctors to monitor treatment with aromatase inhibitors routinely given to breast cancer patients to block estrogen.

The new method should make that much easier, the researchers said, and it might be practical for other conditions that require hormone level monitoring, such as infertility.

However, Wheeler said that the device and approach are still in the early stages of development. "We anticipate within the next five years a product based on this technique would be available," he said.

An American Cancer Society epidemiologist who was familiar with the report agreed that much more work is needed before the device will be ready for "prime time."

Dr. Susan Gapstur, vice president of epidemiology for the society, said that the validity of the measurements needs to be assessed but, if the findings hold up, such a device could be very useful.

"It is well known that estrogen is associated with breast cancer risk," Gapstur said. Typically, estrogen levels in the blood are measured, but those levels usually are lower than levels in breast tissue, she said. Breast estrogen levels can be measured by obtaining nipple aspirate fluid, but the fluid is difficult to obtain, especially from older women, she explained.

"Therefore, a device which can measure breast tissue estrogen, which obtains the samples in a painless and quick manner, would be very useful for studies of breast cancer risk and prevention," she said.

More information

BreastCancer.org has more about breast cancer screening.

Posted: October 2009


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