The prognostic value of nucleolar organiser regions in colorectal cancer: a 5-year follow-up study.

Nucleolar organiser regions (AgNORs) are loops of ribosomal DNA which reflect the cellular activity or malignant potential of the cell and are identified by a specific staining technique. The purpose of this study was to assess the prognostic value of AgNORs in colorectal cancer and to compare it with other accepted prognostic methods. We studied 164 patients who were surgically staged for colorectal cancer and who had complete follow-up data available for 5 years. Using a highly specific silver staining and counting technique each patient was given an AgNOR score. There were 5 Dukes' C tumours, 108 were Dukes' B and 5 were Dukes' A. No cancer deaths occurred in patients with Dukes' A tumours. The incidence of well-differentiated, moderately-differentiated and poorly-differentiated tumours was 37.2%, 53.7% and 9.1%, respectively. Non-survivors had significantly higher AgNOR scores compared with survivors (mean value +/- SD, 14.2 +/- 0.9 vs 8.2 +/- 0.6, P less than 0.0001). In a regression analysis model AgNOR score was the most significant individual variable for predicting survival (chi 2 = 15, P less than 0.01) when compared with Dukes' classification, histological grade, tumour depth or vascular invasion.