title: Immunohistochemical expression of potential therapeutic targets in canine thyroid carcinoma.
abstract: BACKGROUND
  Thyroid carcinoma is a common endocrine tumor in the dog. Local invasive growth frequently precludes surgical excision and, in up to 38% of dogs, the tumor has already metastasized by the time of diagnosis. Therefore, it is important to investigate new treatment modalities that may be useful for the large number of dogs with inoperable tumors or metastatic disease.
  
  
  OBJECTIVE
  To investigate the immunohistochemical expression of potential therapeutic targets in canine thyroid tumors.
  
  
  METHODS
  74 dogs with thyroid neoplasia.
  
  
  METHODS
  Immunohistochemistry was performed for thyroglobulin, calcitonin, vascular endothelial growth factor (VEGF), p53, cycloxygenase-2 (cox-2), and P-glycoprotein (P-gp).
  
  
  RESULTS
  Fifty-four (73%) tumors were classified as follicular cell thyroid carcinomas (FTCs) and 20 (27%) as medullary thyroid carcinomas (MTCs). Eighty percent of FTCs and all MTCs had a high percentage (76-100%) of neoplastic cells immunopositive for VEGF. Thirteen percent of FTCs and 50% of MTCs expressed cox-2. Seven percent of FTCs and 70% of MTCs expressed P-gp. No tumor was immunopositive for p53 expression. Expression of VEGF (P = .034), cox-2 (P = .013), and P-gp (P < .001) was significantly higher in MTCs compared to FTCs.
  
  
  CONCLUSIONS
  VEGF is a potential therapeutic target in both FTC and MTC in dogs. Cox-2 and P-gp may be useful molecular targets in canine MTC.
authors.affiliation: Department of Medicine and Clinical Biology of Small Animals, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium.
authors.forename: M
authors.initials: M
authors.lastname: Campos
authors.forename: R
authors.initials: R
authors.lastname: Ducatelle
authors.forename: H S
authors.initials: HS
authors.lastname: Kooistra
authors.forename: G
authors.initials: G
authors.lastname: Rutteman
authors.forename: L
authors.initials: L
authors.lastname: Duchateau
authors.forename: I
authors.initials: I
authors.lastname: Polis
authors.forename: S
authors.initials: S
authors.lastname: Daminet
mesh_terms: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000378:metabolism; D018263:Adenocarcinoma, Follicular / Q000378:metabolism / Q000662:veterinary*; D000818:Animals; D018276:Carcinoma, Medullary / Q000378:metabolism / Q000662:veterinary*; D051546:Cyclooxygenase 2 / Q000378:metabolism; D004283:Dog Diseases / Q000378:metabolism*; D004285:Dogs; D013964:Thyroid Neoplasms / Q000378:metabolism / Q000662:veterinary*; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism
chemical_list: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D016159:Tumor Suppressor Protein p53; D042461:Vascular Endothelial Growth Factor A; D051546:Cyclooxygenase 2
keywords: Cyclooxygenase-2; P-glycoprotein; VEGF; p53