Detecti On Of Circulating Tumor Cells In Patients With Lung Cancer Using A Novel Immunomagnetic Separation Technology

Objectives：The aim of this study is to establish a new method for detecting circulatingtumor cells (CTCs) in phripheral blood of lung cancer patients with high sensitivity andspecificity, which may benefit for detecting micrometastasis in early stage, assessmentof prognosis, monitoring relapse and metastasis, selecting appropriate treatment andjudging therapeutic effect.Methods：（1）A series of experiments was conducted to determine the efficiency oftumor cells isolation, in which varied concentration of A549cells spiked into2mlperipheral blood drawn from healthy donors. The blood was removed of unwantederythrocytes by ammonium chloride lysate, and make the rest of nucleated cellsincubate with anti-EpCAM magnetic beads, then separated and enriched by a specificdetector (include the peristaltic pump, the shaker, the homemade separate container andthe mini-table type vacuum pump). All epithelia cells were retained on a slide becauseof a magnetic force and identified by H&E staining protocol.（2）On the basis of theseresults we calculated the sensitivity and specificity of tumor cells isolation.10bloodsamples taken from healthy individual were also analyzed by this techonolgy.(3)Samples of42patients with lung cancer were assayed for CTCs detection by abovemethod.Results：The recovery rate was ranging from68%～82%by spiking varying numbers ofA549lung cancer cells into2ml blood samples of healthy volunteers. Regression analysis of number of recovered vs. spiked A549cells yielded a regression equation ofy=0.6419x+8.8875and a coefficient of determination of R2=0.996. More tumor cellscould be detected in blood samples spiked into more tumor cells and the recovery rateof different numbers of A549cells in every experiments without statistically significantdifference (P>0.005). Eighteen of the42patients (43%) were found have CTCs inperipheral blood. The positive rate of the CTCs detected from lung cancer patients ishigher with the increase of the tumor size and tumor metastasis. None of the peripheralblood samples of the10healthy subjects analyzed was found to have CTCs.Conclusion： This novel immunomagnetic separation technology provides a new toolallowing for feasible and specific detection of CTCs in lung cancer patients and it hassimple operation, low cost and fast property. The detection result is associated with thetumor progression. It is likely clinically useful in diagnosis and monitoring of lungcancer and may have a role in clinical decision making.