Here, we validated the clinical utility of our previously developed
microfluidic device, GenoCTC, which is based on bottom magnetophoresis, for the isolation of
circulating tumor cells (CTCs) from patient whole blood. GenoCTC allowed 90% purity, 77% separation rate, and 80% recovery of
circulating tumor cells at a 90 μL/min flow rate when tested on blood spiked with
epithelial cell adhesion molecule (
EpCAM)-positive Michigan
Cancer Foundation-7 (MCF7) cells. Clinical studies were performed using blood samples from
non-small cell lung cancer (NSCLC) patients. Varying numbers (2 to 114) of CTCs were found in each NSCLC patient, and serial assessment of CTCs showed that the CTC count correlated with the
clinical progression of the disease. The applicability of GenoCTC to different cell surface
biomarkers was also validated in a
cholangiocarcinoma patient using anti-
EPCAM, anti-
vimentin, or anti-
tyrosine protein kinase MET (c-MET)
antibodies. After
EPCAM-,
vimentin-, or c-MET-positive cells were isolated, CTCs were identified and enumerated by immunocytochemistry using anti-
cytokeratin 18 (CK18) and anti-CD45
antibodies. Furthermore, we checked the
protein expression of PDL1 and c-MET in CTCs. A study in a
cholangiocarcinoma patient showed that the number of CTCs varied depending on the
biomarker used, indicating the importance of using multiple
biomarkers for CTC isolation and enumeration.