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

Abstract

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.