[Expression of BCR/ABL fusion gene in circulating endothelial cells from chronic myelogenous leukemia patients and its clinical significance]

Several studies have shown that the tumor endothelial cells are different from the normal tissue endothelial cells. These tumor endothelial cells may contribute to tumor neo-vasculogenesis. This study was purposed to analyze the biologic features and determine the expression level of CD133 and BCR/ABL fusion gene in circulating endothelial cells (CEC) isolated from peripheral blood of CML patients, as well as to investigate the role of CEC in disease progression. Mononuclear cells were isolated from peripheral blood by density gradient centrifugation; CEC were sorted by MACS and harvested in the endothelial growth medium. The morphologic features of CEC were observed by microscopy, the cell growth rate was calculated by cell counting, and the cells were identified by immunofluorescence staining for the expression of CD31,CD34,VWF and CD133. The expression of BCR/ABL fusion gene was examined by FISH in 12 CML patients. The results indicated that the isolated CEC displayed the typical cobble-stone morphology. These cells could be identified by the positive immunofluorescence staining for CD31, CD34 and VWF, and showed more increased proliferative potential as compared to that of healthy donors. It was found that the positive rate of CD133 was 31.29% in CML patients, which was significantly different from that of healthy donors (P0.05). In 12 CML patients, CEC carried the same chromosome aberration as the leukemia cells (10.77%). Higher expression level of CD133 and BCR/ABL fusion gene positively correlated with progression of disease. It is concluded that the CEC may participate in invasion and angiogenesis in patients with CML and possibly correlate to the spreading and progression of the disease.