Expression of Circulating Microparticles for the Diagnosis of Non-small Cell Lung Cancer: Clinicopathological Correlations and Prognostic Value

Abstract

Increased values of circulating microparticles (MPs) have been reported in solid tumors including non-small cell lung cancer (NSCLC). We therefore investigated the utility of baseline MPs in the clinical setting of patients with NSCLC. Quantification of MPs in the plasma was performed by flowcytometry. Baseline MP values were correlated with clinical patients' characteristics, estimated tumor volume (ETV) and treatment response. Receiver operating characteristics (ROC) curves were plotted to discriminate between patients and controls in order to determine the diagnostic value of circulating MPs in NSCLC. Our prospective study included 134 NSCLC patients (98 at initial diagnosis, ID and 36 at relapse, R) and 30 healthy individuals. The mean of baseline MP numbers was significantly higher in patients presented either at ID or R than in controls (p<0.0001). Basal MP numbers were inversely correlated with ETV values (p=0.04). In addition, the difference in MP levels at diagnosis was significant according to tumor histology (p=0.02) and primary tumor size (p=0.0007). Using ROC analysis, the optimal cutoff value for baseline MPs was 1307 events/µL with a sensitivity and a specificity of 67.3% and 90.0%, respectively. High MPs expression was significantly associated with low-level smoking degree (p=0.001), non-squamous cell types (p=0.017) and decreased tumor size (p=0.003). Our results suggest that high baseline MP values could be an indicator of tumor growth inhibition in NSSLC. Furthermore, high expression of circulating MPs at diagnosis might predict good prognosis in NSCLC patients.