Endothelial cells in peripheral blood of healthy subjects and patients with metastatic carcinomas

Background: A lack of standardized assays and consensus of cell definition has lead to a wide variation in the reported range of circulating endothelial cells (CECs). Methods: An automated rare cell analysis system was used to enumerate nucleated, CD146(+)/CD105(+)/CD45(-)CECs in 4 mL of blood. Results: Recoveries of spiked HUVECs were linear over a range of 0-1,241 cells (R-2 >= 0.99) with recoveries of >= 70% at each spike level. Correlation coefficient values for interopera tor variability and duplicate sample variation were (R-2 = 0.99 and 0.9), respectively Correlation of CEC counts between tubes 1-2 and 2-3 drawn from the same subject in sequence differed (R-2 = 0.48 and 0.63, respectively). The normal CEC reference range established in 249 healthy donors was 1-20 CECs/mL blood. CEC counts were significantly higher in the 206 metastatic carcinoma patients (P < 0.0001). Conclusion: CECs can be accurately and reproducibly enumerated in blood and arc elevated in metastatic carcinomas compared with healthy donors. Phlebotomy procedures can affect endothelial cell counts. (c) 2007 International Society for Analytical Cytology.