Nucleolar organiser regions in different colonic epithelia

The argyrophilic technique (AgNOR) was applied to paraffin sections of 10 acute self-limited colitis, 15 ulcerative colitis (UC), 5 ulcerative colitis with indefinite dysplastic change, 10 adenomatous polyps, 20 colorectal adenocarcinomas and 10 normal colorectal mucosa. The mean number of nucleolar organiser regions (NORs) per nucleus ranged between 1.62-2.00 (95% CI 1.77-1.93) for normal colon, 2.47-3.80 (95% CI 2.71-3.21) for acute colitis, 1.66-2.75 (95% CI 2.13-2.44) for UC, 3.60-4.00 (95% CI 3.67-3.94) for UC with indefinite dysplasia, 3.00-4.04 (95% CI 3.41-3.81) for adenomatous polyps and 3.59-6.70 (95% CI 4.04-4.72) for colorectal adenocarcinoma. The differences observed were statistically significant. There was a significant difference of AgNOR counts between adenomatous polyp and UC with indefinite dysplasia in comparison to those observed in regenerative epithelium of acute colitis and UC without dysplasia. Hence the technique may be used as an adjunct to routine histology for delineating dysplastic changes in colonic epithelium.