Gradient separation of normal and malignant cells. II. Application to in vivo tumor diagnosis.

Data were obtained concerning the usefulness of discontinuous Ficoll and Isopaque-Ficoll gradients in separating malignant from non-malignant cells from a variety of sources. Most of the material was from effusions, but there is no theoretical restriction of the methods to effusions. Animal and human material were studied, utilizing non-malignant as well as malignant material, the former acting as controls. In the discontinuous Ficoll gradient, concentration of malignant cells at a specific interface was mainly a function of cell density. Thus, while most malignant cells banded in the last two fractions, adenocarcinomas, especially those high in mucus (which decreases total cell density) banded higher in the gradient. The Isopaque-Ficoll technique also proved useful in concentrating malignant cells. The advantage of the discontinuous Ficoll gradient was its ability to separate cells from small specimens (1-10 X 10(6) cells). Contrarily, the Isopaque-Ficoll gradient was preferable for processing specimens of larger volumes.