Identification of abnormal cells in short term monolayer cultures of human tumor specimens

This work was undertaken to verify that when short term monolayer cultures are prepared from human malignant biopsy specimens, the cells which grow are tumor cells and not normal cells from the stroma. A wide range of human tissues, both normal and malignant, was used to obtain monolayer cultures and chromosome spreads were prepared by a modification of standard procedures. The cells were Feulgen stained and DNA values were obtained for cells arrested in mitosis. Metaphase DNA values for normal cells and for cells from a benign tumor were constant, close to the expected value relative to bull sperm, and showed little spread about the mean. Metaphases from malignant cells had abnormal mean DNA values, and generally showed much greater spread about the mean. Results confirm that for cells grown in vitro from tumor biopsies, those which are in the cell cycle and reach mitosis are abnormal and presumably malignant. This is evidence in favor of this type of short term culture as a method for studying the properties of human tumor cells.