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




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).


An automated rare cell analysis system was used to enumerate nucleated, CD146+/CD105+/CD45 CECs in 4 mL of blood.


Recoveries of spiked HUVECs were linear over a range of 0–1,241 cells (R2 ≥ 0.99) with recoveries of ≥70% at each spike level. Correlation coefficient values for interoperator variability and duplicate sample variation were (R2 = 0.99 and 0.90), respectively. Correlation of CEC counts between tubes 1–2 and 2–3 drawn from the same subject in sequence differed (R2 = 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).


CECs can be accurately and reproducibly enumerated in blood and are elevated in metastatic carcinomas compared with healthy donors. Phlebotomy procedures can affect endothelial cell counts. © 2007 International Society for Analytical Cytology