Cytological differences between normal and malignant human cell populations in culture.

Cells from early-passage cultures of normal and malignant human tissues were analyzed for the presence of multiple nucleoli and tri- or multipolar mitoses; these properties are characteristic of malignant cell populations in tissue sections. For the cell types examined the presence of tri- or multipolar mitoses was characteristic of cells of malignant origin. Within epithelial cell populations, cells containing more than 4 nucleoli were found in populations of malignant but not of normal origin; this distinction did not apply to fibroblast populations. Large numbers of cells must be analyzed quantitatively to establish the distinctions described here, since they are properties characteristic of populations, not of individual cells. This approach may facilitate identification of normal and malignant cell populations in primary and early-passage culture.