Clinical Significance and Molecular Characteristics of Circulating Tumor Cells and Circulating Tumor Microemboli in Patients With Small-Cell Lung Cancer

PURPOSE: Circulating tumor cells (CTCs) may have utility as surrogate biomarkers and "virtual" biopsies. We report the clinical significance and molecular characteristics of CTCs and CTC clusters, termed circulating tumor microemboli (CTM), detected in patients with small-cell lung cancer (SCLC) undergoing standard treatment. PATIENTS AND METHODS: Serial blood samples from 97 patients receiving chemotherapy were analyzed using EpCam-based immunomagnetic detection and a filtration-based technique. Proliferation status (Ki67) and apoptotic morphology were examined. Associations of CTC and CTM number with clinical factors and prognosis were determined. RESULTS: CTCs were present in 85% of patients (77 of 97…