A study of colonic adenocarcinoma, with comparison of histopathology, DNA flow cytometric data, and number of nucleolar organizer regions (NORs).

Nucleolar organizer regions (NORs) are loops of DNA encoded for ribosomal RNA production. NORs can be demonstrated in tissue sections with the use of a silver nitrate solution since they are argyrophilic (Ag-NORs). AgNORs have been shown to be increased in a variety of malignant tumors, including colonic adenocarcinoma, when compared to their benign counterparts or corresponding normal tissue. We studied 44 cases of colonic adenocarcinoma to determine whether or not correlations could be found between AgNORs and various histopathologic observations, as well as tumor cell DNA content as determined by flow cytometric analysis. We were unable to demonstrate significant correlations that would justify the use of the AgNOR technique in the daily study of colonic adenocarcinoma.