Flow Cytometry Speeds Cancer Diagnosis

Cancer researchers using flow cytometry have identified breast cancer cells by detecting fluorescent tags labeling a panel of well-documented biomarkers on their surface membranes.

In flow cytometry, a single frequency laser beam is directed onto a hydrodynamically focused stream of liquid. A number of detectors are aimed at the point where the stream passes through the light beam: one in line with the light beam (forward scatter or FSC), several perpendicular to it (side scatter or SSC), and one or more fluorescent detectors. Each suspended particle passing through the beam scatters the light in some way, and fluorescent chemicals in the particle may be excited into emitting light at a lower frequency than the light source. The detectors pick up this combination of scattered and fluorescent light, and by analyzing fluctuations in brightness at each detector (one for each fluorescent emission peak) it is possible to deduce various facts about the physical and chemical structure of each individual particle. FSC correlates with the cell volume, and SSC depends on the inner complexity of the particle.

Investigators at the University of Illinois (Chicago, USA; ) utilized flow cytometry to detect fluorescent-labeled monoclonal antibodies specific for the estrogen receptor (ER), progesterone receptor (PR), and HER-2/neu that are overexpresssed in the membranes of breast cancer cells.

They reported in the February 2006 issue of Experimental and Molecular Pathology that ER, PR, and HER-2/neu marker expressions in five out of five cell lines were consistent with expression patterns established with time-consuming immunohistochemistry techniques.

"If this technique fulfills its promise, one day soon a lab would receive a tumor tissue sample shipped to us in the morning and have the sample analyzed and typed in time to ship back overnight to the physician making the follow-up treatment decisions,” said senior author Dr. Rafael Nunez, assistant professor of medicine at the University of Illinois. "What now takes weeks or months, with results sometimes coming too late to be useful in treatment decisions, could be done in a matter of hours for a fraction of the current cost.”



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University of Illinois, Chicago