QUANTITATIVE ANALYSIS OF CIRCULATING LUNG CANCER CELLS IN THE PERIPHERAL BLOOD BY FLOW CYTOMETRY

Objective To analyse circulating lung cancer cells in the peripheral blood by flow cytometry.Methods The monocyte fraction in the peripheral blood was isolated by Ficoll Hypaque gradient centrifugation.The cells obtained were labeled with antibodies against CD45,cytokeratin (CK) and antigen (2F7/S5A)expressed on lung cancer cells. The CD45 -CK +2F7/S5A + cells were analyzed by flow cytometry and their concentration per liter of blood was calculated.Results (1) The phenotype of blood monocytes was CD45 +CK -2F7/S5A -,while that of small cell and non small cell lung cancer cells was CD45 -CK +2F7/S5A +。Therefore,using this method one lung cancer cell can be detected in one million of white blood cells,with sensitivity of 5 cancer cells per milliliter of blood.(2)The CD45 -CK +2F7/S5A + cells were detected in none of 15 healthy objectives nor 7 patients with benign pulmonary diseases.Meanwhile,fourteen cases out of 40 lung cancer patients(35 %) were found to have cancer cells in the peripheral blood,with the concentration of 10 5 cancer cells/L blood.Conclusion The method described herein has a good sensitivity and specificity for detection of lung cancer cells in the peripheral blood.$$$$