pubmed-article:7525511 | pubmed:abstractText | Nucleolar organizer regions (NORs) are loops of ribosomal DNA that occur in nucleoli and that transcribe to ribosomal RNA. NORs have been identified by means of the Ag-NOR technique in routinely processed tissues, and were found to be of discriminative value between some types of benign and malignant lesions. | lld:pubmed |