Nucleolar organising regions in cervical intraepithelial neoplasia.

The variations in the numbers of nucleolar organising regions (NORs) among different grades of cervical intraepithelial neoplasia (CIN) were investigated using a silver staining technique. Twenty four biopsy specimens were studied (six normal and six of each of the three grades of CIN) by staining paraffin wax sections using a silver (AgNOR) method that stains the NORS as multiple black dots within nuclei (AgNORs). The number of AgNORs in the nuclei of cells in the basal half of the squamous epithelium was counted, and the average number of AgNORs in each cell calculated for each specimen (the AgNOR count). There was no difference in the number of AgNORs in the squamous epithelium of normal biopsy specimens and those showing CIN1 and CIN2, but there was a small but significant increase in the CIN3 group.