Circulating endothelial progenitor cells (cEPCs) play an important role in cancer development.Previous studies showed that serum carcinoembryonic antigen (CEA) levels and the number of circulating endothelial progenitor cells (cEPCs) in the peripheral blood are both involved in tumor neoangiogenesis,and can be used for monitoring tumor progression,recurrence,metastasis,and therapeutic responses.However,the clinical relevance of these biomarkers remains unknown.In this study,40 colorectal cancer (CRC) patients and 17 healthy volunteers were recruited and the amount of cEPCs in the peripheral blood was measured by flow cytometry.The serum CEA level was determined by CEA-RIACT assay.Results showed that cEPC level positively correlated with the stage of the disease,but not with the age and gender of the patients.Moreover,patients with higher serum CEA levels had higher cEPC levels.These results provide clinical evidence for a correlation between two commonly used biomarkers.Further understanding the role of serum CEA in cEPC-mediated tumor vascularization may improve clinical CRC diagnosis and provide useful insights into the design of therapeutic interventions that target tumor vasculature.