Enrichment of malignant cells from pleural effusions by Percoll density gradients

A simple method of separating cells according to their cellular densities is described. The distribution of pleural effusion cells of patients with pulmonary cancer was studied using Percoll discontinuous density gradients. Three density layers (1.050, 1.080 and 1.124 gm/ml) were used to separate the cells. After centrifugation (1,200 g for 20 minutes), the malignant cells were highly enriched on the 1.050 gm/ml layer while the cells situated on the 1.080 gm/ml layer consisted mostly of white cells and a few tumor cells. All red cells were located on the 1.124 gm/ml layer. This separation procedure for the enrichment of tumor cell concentrations seems to be useful for detecting malignant cells in pleural fluids and studying their characteristics.