Using a chip to process blood samples, doctors can monitor the amount of cancer cells in a patient's blood to determine how well a treatment is working by the fourth week, according to a new University of Michigan study.
The "GO chip" was developed by Sunitha Nagrath's team and first demonstrated in 2013. It traps cancer cells like a piece of flypaper traps flies. But unlike flypaper, the chip only catches its target. Antibodies mounted on microscopically thin sheets of graphene oxide in the chip—which give the device its name—recognize a wide array of cancer-specific protein markers found on the surfaces of cancer cells.
As the blood is pushed through channels in the chip, the antibodies trap cells, eventually concentrating enough to work with. With the cells locked in place, the researchers can not only count them but confirm that they are indeed cancerous and determine how the cells' biochemistry varies between patients and treatment stages.
To test that the GO chip could monitor lung cancer treatments, the researchers used it to collect cancer cells from the blood of 26 patients receiving both chemotherapy and immunotherapy for stage 3 lung cancer. The researchers took samples before cancer treatment and after the patients' first, fourth, 10th, 18th and 30th weeks of treatment.
Their experiment revealed that when the number of cancer cells in a patient's blood doesn't decrease by at least 75% by the fourth week of treatment, their cancer is more likely to persist after treatment.
The study also showed that cancer cells collected from patients whose cancer did not respond to treatment had activated genes that may have made the cancer resilient. These genes might be good targets for future cancer therapies, but further study is required to test this idea.
The U-M study is published in the journal Cell Reports.
