Circulating tumor cells (CTCs) and endothelial cells (CECs) in malignant pleural mesothelioma (MPM) and primary lung cancer (LC)

Abstract

11019 Backgrounds: CTC, a surrogate of distant metastasis, and CEC, a marker of angiogenesis, are potentially useful in diagnosis and decision-making of therapy of malignant tumors, and CTC evaluated by the “CellSearch” system has been established as a prognostic marker of metastatic breast cancer patients. The clinical significance, however, has not been examined in other malignant tumors. Methods: We quantitatively evaluated CTC/CECs in peripheral blood (7.5mL/4.0mL) taken from 36 malignant pleural mesothelioma (MPM; epithelioid-type, n=34) and 34 primary lung cancer (LC; adenocarcinoma, n=25) patients treated from October to December, 2007 by using the “CellSearch” system. In 10 patients (one with MPM and 9 with LC), CTCs in blood sampled during operation from a pulmonary vein of the primary tumor site (PV-CTC) were also examined. Results: CTC in peripheral blood was positive in 28% (10/36) of MPM and 47% (16/34) of LC patients, and CTC was not detected in any patient with non-malignant disease (n=11). The mean CTC number and the percentage of CTC-positive patients tended to increase along with advance in tumor-stage, whereas the difference did not reach a statistical significance in MPM or LC (Table). The percentage of CTC-positive patients was significantly higher in resectable-LC patients than in unresectable-LC patients (65% vs 29%; p<0.05).; among operated patients, the percentage was increased along with lymphatic and/or blood vessel invasion. Of noted, PV-CTC was positive in one stage-II MPM and two stage-I LC patients. The mean CEC number of LC patients was 100.9, which was significantly higher that of non-malignant patients (49.9; P<0.05) and was similar to that of MPM patients (86.2). The CEC number of MPM and LC patients tended to increase along with tumor progression (Table). Conclusions: CTC and CEC are potentially useful clinical marker in the diagnosis of MPM and LC. When CTC or PV-CTC is positive, adjuvant chemotherapy may be indicated even for early-stage patients. CTC/CEC in MPM and LC MPM (malignant pleural mesothelioma) LC (primary lung cancer) CTC-positive Pts Mean No. of CTCs Mean No. of CECs CTC-positive Pts Mean No. of CTCs Mean No. of CECs Stage I 50% (1/2) 0.5 (0-1) 42.0 33% (4/12) 0.7 (0-3) 48.8 Stage II 0% (0/4) 0.0 (-) 55.0 33% (1/3) 0.3 (0-1) 65.3 Stage III 31% (4/13) 2.5 (0-27) 61.0 33% (1/3) 2.3 (0-7) 180.0 Stage IV 27% (4/15) 0.4 (0-2) 100.4 63% (10/16) 5.5 (0-42) 129.0 All Pts 28% (10/36) 1.1 (0-27) 86.2 47% (16/34) 3.1 (0-42) 100.9 CTC, circulating tumor cell; CEC, circulating endothelial cell No significant financial relationships to disclose.