Researchers, including a team at Stanford, are working to develop methods to identify biomarkers that can warn of cancer when the disease is in its earliest stage. Such diagnostic tests might detect stray cancer cells in the bloodstream that signal a tumor is spreading, increase effectiveness of treatments and potentially boost patient survival rates.
Designing tests sensitive enough to accurately capture the handful of cancer tumor cells in a blood sample, which contains a sea of red and white blood cells, platelets and other particulates, has proven to be significant challenge for researchers. But findings (subscription required) recently published in the Proceedings of the National Academy of Sciences suggest that a group of UC Los Angles researchers is making promising advancements.
The UCLA system combines an camera capable of snapping clear images of rapidly-moving cells, a powerful optical microscope and high-speed image processor. Scientific American reports:
The heart of the U.C.L.A. system is an ultrafast microscopic camera the researchers introduced in 2009 that captures images at about six million frames per second. This "serial time-encoded amplified microscopy" (STEAM) camera creates each image using a very short laser pulse--a flash of light only a billionth of a second long. The STEAM camera's shutter speed is 27 picoseconds, about a million times faster than a current digital camera. (A picosecond it one trillionth of a second.)
The U.C.L.A. camera converts each laser pulse into a data stream from which a high-speed image can be assembled. The team used this technology to identify breast cancer cells in a blood sample. "We look at the cell's shape, size and texture as well as its surface biochemistry," [lead author Keisuke Goda, PhD,] explains. "We can tell through high-speed imaging that cancer cells tend to be larger than white or red blood cells. And we know that a cancer cell's shape is ill-defined compared to red and white blood cells."
The team's next step is to use the system to complete clinical testing on blood samples from breast, lung, stomach, prostate and intestinal cancer patients.
Previously: Tumors can grow for decades before blood-based detection, study shows, Study finds huge genetic diversity in cancer cells and Could a blood test detect early signs of emphysema?
Photo by Annie Cavanagh, Wellcome Images