Argyrophilic proteins of the nucleolar organizer region in bladder-tumours

The introduction of a simple one-stage silver nitrate stain as a method of displaying nucleolar organizer regions (NOR's) in formalin-fixed tissue has made it possible to examine the significance of these structures in tumour pathology. In the current study argyrophilic proteins of the NOR's were studied in 39 consecutive patients with bladder tumours. The results indicate that the counting of silver staining particles is only of limited value in grading bladder tumours and that this method is not superior to other additional grading techniques such as histo-morphometry and flow cytometry.