CellCollector®: A novel method for the isolation of circulating tumor cells (CTC) in vivo and ex vivo in lung cancer patients during therapy

Introduction: The isolation and characterization of CTCs is a promising tool for taking care of cancer patients. In a pilot study we used a newly developed CellCollector^® (Gilupi, Germany) for the in vivo and ex vivo isolation of CTCs. This CellCollector consists of a gold coated steel wire with a polymer on top holding anti-EpCAM directed antibodies. Methods: We included 32 late stage lung cancer patients of whom 24 were examined in vivo and 25 for the ex vivo study. They were examined before and during therapy. A CellCollector was either placed into the cubital arm vein for 30 min or incubated in vitro for 90 min in 8.5 mL EDTA-stabilized blood. The attached cells were stained, counted, and histomorphologically characterized. Results: While in 18/96 (19%) of the ex vivo applied wires CTCs could be retrieved this number was 57/92 (62%) in vivo. The cell numbers on the ex vivo wires ranged from 1 to 3 and in vivo from 1 to 92 cells. On 15 CellCollectors used in vivo we found a variable number of cell clusters, the majority consisting of 2-3 cells. Statistical analysis revealed no association between the CTC number on the in vivo wires and the clinical results (progressive disease vs. response). Conclusion: This is the first study correlating the number of CTCs after in vivo application of the CellCollector system with the clinical course of the disease. Our preliminary results demonstrate the feasibility of this method for the characterization of CTCs in lung cancer patients. Larger studies are needed to clarify whether a therapy monitoring is also possible. The molecular analysis of the collected cells is in preparation and will be reported.