Detection of circulating tumor cells by reverse transcriptase-polymerase chain reaction in patients with resectable non-small-cell lung cancer

Abstract

We tested whether circulating tumor cells can be detected in the peripheral blood of patients with resectable non-small-cell lung cancer (NSCLC) by reverse transcriptase-polymerase chain reaction (RT-PCR) of carcinoembryonic antigen (CEA) mRNA. We assayed for CEA mRNA by RT-PCR in the peripheral blood, taken at the time of diagnosis before surgical intervention and again 2 to 3 weeks postoperatively, from 103 patients with NSCLC who underwent curative lobectomy. Blood samples taken from 15 patients with interstitial pulmonary fibrosis who underwent an open-lung biopsy and from 32 healthy subjects served as controls. No control samples were positive for CEA by RT-PCR. Sixty-two (60%) of the preoperative blood samples from the 103 patients with NSCLC were positive. Of these 62 samples, 27 (44%) remained positive even after surgical intervention, whereas the remaining 35 samples (56%) became negative. The incidence of positive CEA mRNA correlated highly with pathologic TNM stage of disease in both the preoperative and postoperative blood samples. Many patients with resectable NSCLC have detectable levels of circulating cells expressing carcinoembryonic antigen even after surgical intervention. Such patients may have a higher rate of relapse.