ABSTRACT
Circulating tumor cells (CTCs) are those cells that separate from tumors and spread through the blood and lymphatic systems to create secondary tumors [1-3]. This process is known as metastasis and constitutes the most dangerous phase of cancer. Detection of CTCs can indicate the onset of metastasis or relapse and the absence of CTCs may indicate remission of disease. Thus, detection of CTCs is an important, emerging area of cancer research and many methods are being investigated for optimal detection. Researchers have used RT-PCR, •uorescence •ow cytometry, immunomagnetic separation, and micro•uidic devices to detect and separate CTCs [4-7]. Each of these technologies brings advantages and unique challenges and limitations, though they all suffer from long preparation and testing time, lack of sensitivity, or the need for dedicated technicians to evaluate results. For instance, in immunomagnetic separation, CTCs are captured on a magnetic array after they have been tagged with ferrous beads via antibody-specic attachment. After the cells have been captured, a cytologist must view the magnetic array to positively identify captured cells.
