The distribution of nuclear DNA from human brain-tumor cells

Abstract

Flow cytometry (FCM) is a technique that measures the quantity of DNA contained in individual nuclei and records a frequency distribution of the DNA content per nucleus in the sampled cell population. Nuclei from a variety of human brain tumor types were isolated by tissue grinding, purified by centrifugation through 40% sucrose (15 min at 4000 rpm), fixed with 10% formalin, stained with acriflavine-Feulgen and analyzed by FCM. Profiles of DNA distribution in histologically benign tumors, such as meningiomas, pituitary adenomas, neuroblastomas and low-grade astrocytomas, revealed a large diploid population (2C) with a few nuclei in DNA synthesis, as well as a small premitotic population (G2 cells) that contains a 4C DNA complement. Malignant gliomas, including glioblastomas, consist of more cells in DNA synthesis. These tumor cells show a highly variable distribution of ploidy consisting not only of diploid, and/or aneuploid, but also triploid, tetraploid and possibly octaploid populations. A large variability between different regions of each tumor was always observed. Metastatic brain tumors, despite the fact that they contain a considerable number of cells undergoing DNA synthesis, demonstrate little variability within each individual tumor. The ability of rapidly characterize the cell populations of human brain tumors with FCM may enhance the effectiveness of their clinical management.