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In the present study various AgNOR parameters were assessed in the computer-aided image analysis and involved the normal epithelium of colon both superficial and epithelium of crypts, adenomas and carcinomas of colon in humans. It indicated that the number and area of AgNOR dots was highest in carcinomas and decreased stepwise from carcinomas through adenomas and the epithelium of crypts to the superficial epithelium. Other parameters such as: the ratio of AgNOR dot area to nuclear area and the size of single dots were different only in the superficial epithelium. The number of AgNOR separate locations showed a tendency for higher values in neoplasms. In neoplastic lesions and normal epithelium there was a positive correlation (p < 0.0001) between AgNOR dot area and nuclear area.

NORs are the loops of DNA containing ribosomal genes which are associated with non-histonic argyrophilic proteins. It permits their identification by using specific argyrophilic staining. NORs are visualized in light microscopy as AgNOR dots or argyrophilic NOR dots. Neoplastic and proliferative cells show differences with respect to the number, area and distribution of AgNOR dots. Major difficulties in the analysis of AgNOR dots are caused by technical problems associated with staining and fixation of the tissue. In our study we found that correct fixation of nucleolar proteins associated with AgNORs was a decisive factor in correct interpretation of the results.