Elevated levels of circulating endothelial progenitor cells in head and neck cancer patients

Background and Objectives Measurement of circulating endothelial cells (CECs) and progenitor cells (EPCs) has potential as a surrogate marker for monitoring anticancer treatment. This study evaluated the significance of CECs and EPCs in the blood of patients with head and neck squamous cell carcinoma. Methods In a prospective trial fresh blood samples from 22 tumor patients and 18 controls were tested using multiparametric flow‐cytometry. CECs were defined as CD31 + /CD146 + and CD45 − /7AAD − . EPCs were defined as CD133 + /KDR + and CD3 − /CD19 − /CD33 − /7AAD − . Results Median levels (min/max) of CECs in the tumor group were 2 (0/5) at the time of diagnosis, 1 (0/5) 1 year after therapy and 2 (0/6) in the control cohort. Median levels of EPCs were 5 (1/41) before and 10 (0/21) after treatment in the tumor group compared to 2 (0/7) in the control cohort ( P  < 0.001 and P  = 0.03). CEC and EPC levels showed no apparent correlation with tumor size and response to radiotherapy after 18 months of observation. Conclusions In this pilot study CD133 + /KDR + EPCs were significantly elevated in head and neck tumor patients before and after therapy. Our results warrant further studies on the use of EPCs as a surrogate marker for anticancer therapies in these patients. J. Surg. Oncol. 2008;98:545–550. © 2008 Wiley‐Liss, Inc.