Accuracy and ease of cancer diagnosis improved by new technique
Measuring the physical properties of individual cells in body fluids can diagnose cancer with a high degree of accuracy. This technique uses a deformability cytometer to analyze individual cells. It could reduce the need for more cumbersome diagnostic procedures along with the associated costs, as well as improve accuracy over current methods.
The results of the initial clinical study, which analyzed pleural fluid samples from more than 100 patients, was published in Science Translational Medicine (2013; doi:10.1126/scitranslmed.3006559). It was carried out by a research team from the University of California at Los Angeles (UCLA) and from Harvard University in Boston, Massachusetts.
Pleural fluid, a natural lubricant of the lungs as they expand and contract during breathing, is normally present in spaces surrounding the lungs. Medical conditions such as pneumonia, congestive heart failure, and cancer can cause an abnormally large buildup of the fluid, a pleural effusion.
When cytopathologists screen for cancer in pleural effusions, they perform a visual analysis of prepared cells extracted from the fluid. Preparing cells for this analysis can involve complicated and time-consuming dyeing or molecular labeling, and the tests often do not definitively determine the presence of tumor cells. As a result, additional costly tests are often required.
The method in this study requires little sample preparation, and instead relies on the imaging of cells as they flow through in microscale fluid conduits.
Imagine squeezing two balloons—one filled with water and one filled with honey. The balloons would feel different and would deform differently in your grip. The researchers used this principle on the cellular level by using a fluid grip to "squeeze" individual cells that are 10,000 times smaller than balloons—a technique called deformability cytometry. The amount of a cell's compression can provide insights about the cell's makeup or structure, such as the elasticity of its membrane or the resistance to flow of the DNA or proteins inside it. Cancer cells have a different architecture and are softer than healthy cells and, as a result, deform differently.
Using deformability cytometry, researchers can analyze more than 1,000 cells per second as they are suspended in a flowing fluid, providing significantly more detail on the variations within each patient's sample than could be detected using previous physical analysis techniques.
The researchers also noted that the more detailed information they obtained improved the sensitivity of the test—some patient samples that were not identified as cancerous via traditional methods were found to be so through deformability cytometry. These results were verified 6 months later.
"Building off of these results, we are starting studies with many more patients to determine if this could be a cost-effective diagnostic tool and provide even more detailed information about cancer origin," said co-principal investigator Dino Di Carlo, PhD, associate professor of bioengineering at the UCLA. "It could help to reduce laboratory workload and accelerate diagnosis, as well as offer doctors a new way to improve clinical decision-making."