Histology and cell proliferation in human bladder tumors.An autoradiographic study

Abstract

The rate of cell proliferation, expressed as the potential doubling time, TPD, of 70 bladder tumors of all degrees of differentiation, and of transitional epithelium from 19 patients without bladder tumors, was evaluated from the labelling index after in vitro incorporation of 3H-Thymidine, and compared with the histologic growth pattern and the degree of epithelial anaplasia. It was demonstrated that the rate of cell proliferation in bladder tumors increased significantly with increasing grade of histologic malignancy, and was considerable compared with that of normal bladder epithelium. Papillary tumors showed a greater rate of cell proliferation compared to that of intraepithelial and solid growths of the same degree of anaplasia. The discrepancy between TPD and the growth rate known from clinical experience is best explained by extensive cell loss as a major parameter in the growth pattern of bladder tumors. It was concluded from the labelling pattern that only a proportion of the tumor cell population was proliferating. The implications of this phenomenon for therapy are discussed.