Correlation between in vitro autoradiographic results and histological WHO grades in human urothelial bladder tumours

253 biopsy specimens of 106 urinary bladder tumours have been examined by means of in vitro autoradiography and the results compared with the WHO grading. An increase of the average labelling index occurred parallel to increasing WHO grades. However, great inter-tumorous differences in proliferation behaviour existed particularly in papillary G2 and G3 urothelium carcinomas. Possible causes of this heterogeneity are discussed. In vitro autoradiography is a suitable method for the objective characterization of the malignancy potential of urinary bladder tumours.