title: Argyrophilic nucleolar organizing regions and Ki67 equally reflect proliferation in fine needle aspirates of normal, hyperplastic, inflamed, and neoplastic canine lymph nodes (n = 101).
abstract: BACKGROUND
  The count of argyrophilic nucleolar organizing regions (AgNOR) has been considered a useful variable that reflects cellular proliferation in canine lymph nodes, but it has not been compared with other markers of proliferation.
  
  
  OBJECTIVE
  Ki67 and AgNORs are equally useful as markers of tissue proliferation in fine needle aspirates of canine lymph nodes.
  
  
  METHODS
  A total of 101 dogs.
  
  
  METHODS
  Prospective, observational study of a convenience sample of dogs. Two smears were prepared for a May-Gruenwald-Giemsa stain and a Ki67/AgNOR double stain. In addition, CD3/CD79a immunostaining was performed when cytologic examination revealed a lymphoma. The dogs were grouped as normal (n = 26), reactive hyperplasia (n = 25), lymphadenitis (n = 31), and lymphoma (n = 19), based on the physical examination and the cytologic findings. The AgNOR count/cell, AgNOR area/cell and the percentage of cells staining positive for Ki67 were evaluated in 100-167 cells (median, 113 cells) by using automatic image analysis.
  
  
  RESULTS
  Mean (SD) AgNOR counts/cell were 1.36 +/- 0.19 in normal dogs, 1.55 +/- 0.26 in lymphadenitis, 1.65 +/- 0.32 in reactive hyperplasia, and 3.67 +/- 1.08 in lymphoma. The percentage of Ki67 positive cells was 2.67 +/- 0.99% in normal lymph nodes, 5.04 +/- 3.34% in lymphadenitis, 5.36 +/- 2.14% in reactive hyperplasia, and 30.2 +/- 10.8% in lymphoma. All variables were significantly higher in dogs with lymphoma compared with the other groups (P < .0001). The sensitivity and the specificity of the AgNOR count for diagnosing lymphoma were 95 and 96% at a cutoff value of >2.04 AgNORs/cell. The cutoff value for the Ki67 positive cells was >10.40% (sensitivity, 95%; specificity, 98%).
  
  
  CONCLUSIONS
  The results indicated that both AgNOR and Ki67 counts were good diagnostic tools for assessment of proliferation in aspirates of canine lymph nodes.
authors.affiliation: Clinic of Small Animals, Clinical Pathophysiology and Clinical Pathology, Justus-Liebig University Giessen, Germany. natalie.bauer@vetmed.uni-giessen.de
authors.forename: Natali B
authors.initials: NB
authors.lastname: Bauer
authors.forename: Daniela
authors.initials: D
authors.lastname: Zervos
authors.forename: Andreas
authors.initials: A
authors.lastname: Moritz
mesh_terms: D000818:Animals; D034961:Antigens, Nuclear / Q000378:metabolism*; D019540:Area Under Curve; D044963:Biopsy, Fine-Needle / Q000662:veterinary; D004283:Dog Diseases / Q000175:diagnosis / Q000378:metabolism / Q000473:pathology*; D004285:Dogs; D005260:Female; D006651:Histocytochemistry / Q000662:veterinary; D007091:Image Processing, Computer-Assisted; D019394:Ki-67 Antigen / Q000378:metabolism; D008199:Lymphadenitis / Q000175:diagnosis / Q000378:metabolism / Q000473:pathology / Q000662:veterinary*; D008223:Lymphoma / Q000175:diagnosis / Q000378:metabolism / Q000473:pathology / Q000662:veterinary*; D008297:Male; D009687:Nuclear Proteins / Q000378:metabolism*; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012372:ROC Curve; D012680:Sensitivity and Specificity
chemical_list: D034961:Antigens, Nuclear; D019394:Ki-67 Antigen; D009687:Nuclear Proteins; C051963:nucleolar organizer region associated proteins