Najjar F, et al. - In small-cell lung cancer (SCLC) patients, researchers examined the usefulness of baseline levels of circulating endothelial cells (CECs) and microparticles (MPs) via analyzing data from 56 patients and 41 healthy individuals. They used an immunomagnetic separation (IMS) technique to isolate and quantify CECs in the peripheral blood. Plasma samples were examined using flow cytometry for the measurement of circulating MPs. Either at initial diagnosis or at relapse, baseline levels of CECs and MPs were significantly higher in SCLC patients vs healthy subjects, while estimated tumor volume was significantly correlated with basal MP values, but not pretreatment CECs. In patients with an objective response vs those with progressive disease after treatment, the amount of baseline CECs and MPs was significantly lower. Basal MP values significantly increased in 1-year survivors compared vs non-survivors, while patients with 6-month PFS displayed significantly decreased pretreatment CEC counts. These findings infer that baseline CECs and MPs could be predictive biomarkers of tumor response and long-term survival in SCLC patients.