title: Argyrophilic nuclear organizer regions in nasopharyngeal carcinoma and paraneoplastic epithelia.
abstract: BACKGROUND
  Nucleolar organizer regions (NORs), which are loops of DNA containing ribosomal RNA genes, have been shown to correlate with cell proliferation and malignant transformation. The diagnostic value of silver staining NORs (AgNORs) in preneoplastic epithelia and nasopharyngeal carcinoma (NPC) by the quantitative assessment of AgNORs proteins is evaluated.
  
  
  METHODS
  Silver-staining of NORs was applied to 70 paraffin sections of NPC biopsy specimens, including 29 samples of the adjacent normal glandular epithelia (GE), 19 hyperplastic/dysplastic columnar epithelia (CE) in the adjacent mucosa, 10 hyperplastic/dysplastic squamous epithelia (SE) in the adjacent mucosa, 54 differentiated nonkeratinizing carcinoma (DC), and 16 undifferentiated carcinoma (UC). The morphometric features of AgNORs in preneoplastic epithelia and cancer cells were analyzed by image cytometric analysis and then compared.
  
  
  RESULTS
  The AgNOR count, mean AgNOR area, and AgNOR area-count ratio increased significantly from GE to CE to DC or UC. The mean nuclear area, AgNOR area, and AgNOR area-count ratio increased significantly from GE to SE to UC, whereas overlapping AgNOR values were observed between SE and DC. UC had significantly higher values than DC in mean nuclear area, AgNOR area, and AgNOR area-count ratio.
  
  
  CONCLUSIONS
  The morphometric analysis of AgNORs reflected cell proliferative activity and histologic differentiation of tumor rather than malignant transformation in different nasopharyngeal epithelia and NPC. AgNOR area and AgNOR area-count ratio are the most valuable features for differential diagnosis of normal, preneoplastic, and cancer cells.
authors.affiliation: Department of Pathology, Shantou University Medical College, 22 Xinling Road, Shantou 515031, PR China. MHChen@stu.edu.cn
authors.forename: Maohuai
authors.initials: M
authors.lastname: Chen
authors.forename: Joseph C K
authors.initials: JC
authors.lastname: Lee
authors.forename: Shikyuen
authors.initials: S
authors.lastname: Lo
authors.forename: Jian
authors.initials: J
authors.lastname: Shen
mesh_terms: D000328:Adult; D000368:Aged; D002277:Carcinoma / Q000175:diagnosis / Q000473:pathology*; D002455:Cell Division; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009303:Nasopharyngeal Neoplasms / Q000175:diagnosis / Q000473:pathology*; D009697:Nucleolus Organizer Region / Q000473:pathology*; D011230:Precancerous Conditions / Q000175:diagnosis / Q000473:pathology*; D020545:Respiratory Mucosa / Q000473:pathology*; D016622:Silver Staining