Silver stained nucleolar organizer region proteins (Ag-NORs) as a predictor of prognosis in colonic cancer.

Using a one-step silver nitrate staining technique, routinely processed tumour tissues of 49 carcinomas of the colon were investigated to demonstrate silver-stained nucleoli (Ag-nus) and argyrophilic proteins associated with the so-called nucleolar organizer regions (Ag-NORs). Patients with attempted curative resections and tumour stages Dukes' A, B, C1 and C2, with an uneventful follow-up period of at least 48 months (N = 17), showed a statistically significant (P = 0.0001) lower mean number of scattered Ag-NORs (3.04; SD: 1.08) compared to patients who developed metastases during their follow-up period (N = 15; 5.40; SD: 1.28), as well as to patients who underwent palliative surgical treatment (N = 17; 4.48; SD: 1.67). Mean numbers of scattered Ag-NORs per nucleus and staging of the tumour were strongly related (P = 0.0001) to cancer-specific survival. The results indicate that the evaluation of silver-stained particles according to their different distribution patterns is of great value with regard to the clinical outcome of colonic carcinoma and may even allow a more accurate prognostic assessment of these patients than the WHO grading system, UICC staging system, the so-called Jass-scoring system, and Dukes' classification.