Image analysis of Ag-NOR proteins in transitional cell bladder cancer

Nuclear organizer regions (Ag-NORs) were visualized using the standard silver-staining technique in biopsy specimens from 112 bladder carcinomas. The area of individual Ag-NOR dots and the area of Ag-NOR protein/nucleus were measured using a Quantimet 570 image analyser and the results were then correlated with clinical, histological, and quantitative prognostic factors, and survival. The mean area of Ag-NOR dots was not significantly related to any of the features analysed. The mean area of Ag-NOR protein/nucleus was related to WHO grade (P = 0.0004), papillary status (P = 0.004), DNA ploidy (P = 0.02), S-phase fraction (P = 0.02), mitotic frequency/mm2 of enoplastic epithelium (P = 0.005), mean nuclear area (P = 0.001), and SD of nuclear area (P = 0.001). In the entire cohort, the mean area of Ag-NOR protein/nucleus was related to progression with a borderline significance (P = 0.09), while in survival analysis only Ag-NOR count/nucleus had prognostic value (P = 0.010). In Ta-T1 tumours, Ag-NOR protein area/nucleus predicted progression (T-category) (P = 0.016) and survival (P = 0.014) significantly. Also, the mean area of individual Ag-NOR dots (P = 0.026) and Ag-NOR count/nucleus (P = 0.014) were related to prognosis in Ta-T1 tumours.