Nucleolar organizer region in transitional cell carcinoma of the bladder.

The silver staining technique that identifies NORs (nucleolar organizer regions) associated proteins was used for examining changes in nucleolar organizer region numbers in transitional cell carcinoma of the bladder. This method reveals NORs as black dots in the cell nuclei, and the number of NORs per cell (NORs/cell) has been taught to be related to cellular activation and to be a possible predictor of clinical outcome. A hundred specimens of transitional cell carcinoma of the bladder divided into four histologic grades (Ash classification) with 25 specimens each, and 25 specimens of normal bladder mucosa were analyzed. It has been demonstrated that the amount of protein synthesized by carcinoma varies according to its histologic grade, i.e. the higher histologic grade, the greater the NORs/cell number for each histologic grade. The characteristic mean NORs/cell SD was determined (GI 4.85 +/- 0.82, GII 5.94 +/- 1.42, GIII 8.54 +/- 1.01 and GIV 8.72 +/- 1.42), among which statistically significant differences were found. For similar histologic grades the characteristic mean NORs/cell +/- SD showed no statistically sex and age related differences. In some cases the mean NORs/cell for the examined carcinoma did not match the characteristic mean NPRs/cell +/- SD for the respective histologic grade.