Aaron Wheeler and his team of University of Toronto researchers have developed a device that may lead to pocket-sized detectors to help diagnose and monitor breast cancer. (Oct. 7, 2009)
U of T team's 'lab on a chip' may detect breast cancer
October 07, 2009
Health Reporter
In his left hand, Aaron Wheeler holds a petri dish bearing a lump of breast tissue that resembles, in size and appearance, a piece of chewed gum.
In his right, the University of Toronto chemist holds a microchip array, about the size of a credit card, bearing a drop of red liquid about a thousand times smaller than the glob of mutilated flesh. The drop represents the minute amount of cells that Wheeler's tiny board needs to accurately gauge estrogen levels in a woman's breast tissue.
The invention holds out the promise in the near future of pocket-sized detectors that could help diagnose and monitor breast cancer, which requires high levels of the female hormone to thrive.
It also earned Wheeler's U of T team the inaugural front cover of the world's newest major scientific journal.
"This is the size of tissue that you would normally need to take out to (determine) estrogen levels," says Wheeler, holding out the petri dish. "Obviously we can't routinely be cutting pieces like this out of women's breasts."
Wheeler's work appeared Wednesday on the first cover of the journal Science Translational Medicine, based in Washington, D.C.
An offshoot of the weekly juggernaut Science - one of the world's two most prestigious research publications - the new journal will concentrate on work that is progressing out of the laboratory and into clinics and hospitals.
"This is a huge honour for us to be in that journal at all," says Wheeler, whose collaborators include Dr. Noha Mousa, the lead study author and a PhD candidate in medicine at the school.
"But to be on the cover of the first issue, it's a tremendous honour," he says.
Wheeler also freely admits that the prominent coverage could help attract investors for his device, which he hopes to couple with emerging microchip analyzer technology to create a pocket-sized screener for breast cancer.
Women with such cancers have far higher levels of estrogen in the surrounding tissue than those found in healthy breasts. And there is growing evidence that the hormone, which helps support tumour growth, is greatly elevated in women at risk of developing breast cancer.
Currently, however, these telltale estrogen levels can only be determined by cutting fingertip-sized pieces of tissue out of the breast to analyze in specially equipped laboratories. Because they're so painful and disfiguring, however, such tests are rarely done.
Wheeler says his "lab on a chip" technology would require only a fraction of the sample cells now needed and could be painlessly extracted with a simple needle prick.
The device works by using electrical charges to "dance" droplets of liquids on a precise route over the surface of the microchip circuit array. One solvent droplet is sent over a dried sample of tissue to open up the cellular walls. Another is then sent in to extract the intercellular contents that have been exposed.
That millimetre-wide drop - now bearing the cellular load - is then directed through another liquid reservoir, which removes all the other cellular materials, leaving only the purified estrogen to carry on.
"Then we pull (the droplet) out and do the analysis," Wheeler says.
This extraction and separation is currently done by white-coated lab technicians, using beakers, pipettes and centrifuges, and can take several days to produce results. Wheeler says results from his process would be available in minutes.
Experiments on the tissues of two women with breast cancer have shown that this process extracts enough estrogen to give doctors accurate levels, says Dr. Noha Mousa, the lead study author and a PhD candidate in medicine at the school.
By combining the device with a microchip estrogen detector, the entire process could be exported from the expensive and time-consuming lab settings right into doctor's offices.
The resulting, pocket-sized devices would have at least two uses, says Mousa.
Most importantly, they could be used to monitor the success of estrogen-lowering drugs that are currently used to treat women already suffering breast cancer. But Mousa says they might also be employed as an additional screening tool, along with such things as mammography, to help determine a woman's risk of developing the ailment.
In women with elevated estrogen levels, hormone-lowering drugs like tamoxifen or aromatase inhibitors could be prescribed before any cancers appear, Wheeler says.
Katrina Kelner, editor of the new journal, said the "remarkable device" was a prime example of the benefits born through a marriage of engineering and medicine.
"These little circuits are really amazing," Kelner said in a press teleconference.
"By electronically moving very small droplets of liquid around on a miniature circuit board, they can perform very sophisticated chemical analyses."