Fisk and Vanderbilt researchers look to speed up cancer diagnosis by detecting tumor cells directly from patients’ bloodstreams.
9.13.2016 / By Adrian D. Parker, Sr.
According to the National Cancer Institute, more than 1.6 million Americans will be diagnosed with cancer this year alone, and nearly 600,000 of them will succumb to the disease. Mortality rates vary depending on the type of cancer, but they tend to be highest for so-called aggressive cancers, in which a tumor forms, grows, and spreads quickly. In those cases, the key to increasing a patient’s chances of survival is to diagnose the illness quickly. An interdisciplinary collaboration between Fisk University and nearby Vanderbilt University, is working on a new, nanoscience-driven approach to do just that.
Most cancers are detected using imaging procedures such as CT scans, nuclear scans, ultrasound, MRI, PET scans, and X-ray imaging. But a definitive diagnosis almost always requires a biopsy, in which a sample of living tissue is extracted to determine whether it’s malignant or benign. Extracting a sample may be as simple as drawing it through a needle, or it may require surgery; a tumor may be removed entirely, or just partially. Either way, the sample must be cultured to determine whether it’s cancerous and, if so, whether it’s aggressive. That can take days, a critical amount of time for patients of aggressive cancers.
The Fisk–Vanderbilt collaboration looks to speed up the process by detecting cancer directly from patients’ bloodstreams. “If a tumor is aggressive, it will insert cells, called circulating tumor cells, into the bloodstream to populate other areas of the body,” says Fisk graduate researcher Andrew Cook, who’s spearheading the project. “It is the secondary tumor sites, rather than the primary site, that account for upwards of 90% of cancer-related deaths. A device that can capture and identify circulating tumor cells from blood is minimally invasive and will allow for faster diagnosis.”
The plan, developed by Fisk’s Nanomaterials and Sensors Group in conjunction with Vanderbilt’s Biomedical Engineering department, makes use of an analytical technique known as Surface Enhanced Raman Spectroscopy. It wouldn’t be the first technique designed to diagnose cancer from blood samples. State-of-the art detection tools such as flow cytometry and Enzyme-Linked Immunosorbent Assay (ELISA) use essentially the same approach. But those tools require expensive chemical reagents and either a highly skilled technician or expensive automated instrumentation. They also require large blood samples and have difficulty differentiating between certain cell types.
Raman spectroscopy has its drawbacks, too—mainly that its output signal is inherently weak, which makes it hard to distinguish cancer cells from healthy ones. But Cook and his coworkers seek to boost that signal through a technique known as surface enhancement; silver-coated zinc-oxide nanowires in the device’s microfluidic chamber will help to differentiate between cells.
The group still has a great deal of work left to do before their sensor will be ready for clinical diagnostics. Their current priority is to be able to acquire spectra of single cells. Once they’ve done that and successfully integrated nanowires into a microfluidic channel, design work can begin on the channel that will capture circulating tumor cells.
Cook and his colleagues hope that within 2-3 years they can have a functional, inexpensive biosensor capable of detecting trace amounts of tumor cells in a matter of hours, not days. For the 1.6 million Americans diagnosed with cancer each year, that would be a welcome development. Cancer shows no signs of letting up, but neither do the researchers who’ve made it their mission to stop the disease’s spread.
Adrian D. Parker, Sr. is a graduate student in Computer and Information Systems Engineering at Tennessee State University and a 2016 HBSciU Fellow.
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