Density gradient centrifugation of tumor cells from needle biopsies and their respective source tumors: a comparison of density distributions.

A needle biopsy technique was applied to a murine fibrosarcoma (FSa) tumor system. FSa tumors of 8 mm diameter in size were biopsied and then made into single cell suspensions. Resulting density profiles of cells from both sources were compared following centrifugation in Renografin gradients. In all cases, there was excellent agreement between the density profiles of the material from each of the biopsies and the corresponding solid tumors.