title: Relationship between the immunohistochemistry of the primary tumour and 18F-FDG-PET/CT at recurrence in patients with well-differentiated thyroid carcinoma.
abstract: OBJECTIVE
  In patients thyroidectomized for well-differentiated thyroid carcinoma, the correlation between thyroglobulin (Tg) plasma level and F-fluoro-2-deoxy-D-glucose (F-FDG)-PET results is still a matter of debate. We evaluated whether the immunochemical profile of the primary tumour could be used as a predictor of positivity on F-FDG-PET/computed tomography (CT) when recurrence is confirmed.
  
  
  METHODS
  A total of 26 patients (eight men, 18 women; 51±16 years old) were included. All of the patients had a histologically proven recurrence or a high level of Tg during follow-up and underwent a F-FDG-PET/CT following two intramuscular injections of rhTSH. The F-FDG-PET/CT scans were blindly analysed by three nuclear physicians. The results of the PET scans were classified as true positive, false positive or false negative. Nine antibodies were used for the immunochemical analysis (tissue microarray: hexokinase I, II and III; Tg; vascular endothelial growth factor; and glucose transporter type 1, CD31, CD68 and sodium iodide symporter).
  
  
  RESULTS
  The PET scans were positive for 15 patients and negative for 11 patients. Hexokinase I was expressed in nine of the 26 primary tumours (7/26 for the isoforms). No single molecule expressed in the primary tumours was correlated with the F-FDG-PET/CT results. There was no association of antibody overexpression (clustering) in the primary tumours with the F-FDG-PET/CT results of the recurrences.
  
  
  CONCLUSIONS
  In a larger series, we failed to confirm the preliminary results of Hooft and colleagues. This study did not allow for the determination of a single marker expressed in the primary tumours that would be predictive of F-FDG-PET/CT positivity when recurrence is suspected. Therefore, at present, immunochemistry does not appear to be a definitive tool for predicting the results of F-FDG-PET/CT in cases of recurrence.
authors: Department of Nuclear Medicine, Henri Becquerel Centre, Rouen University Hospital, Rouen, France.
authors: Caroline
authors: C
authors: Lansoy-Kuhn
authors: Jean M
authors: JM
authors: Picquenot
authors: Agathe
authors: A
authors: Edet-Sanson
authors: Férial
authors: F
authors: Mechken
authors: Sophie
authors: S
authors: Laberge-Le Couteulx
authors: Marie
authors: M
authors: Cornic
authors: Pierre
authors: P
authors: Vera
mesh_terms: D016000:Cluster Analysis; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D064847:Multimodal Imaging; D049268:Positron-Emission Tomography; D012008:Recurrence; D013964:Thyroid Neoplasms / Q000000981:diagnostic imaging* / Q000378:metabolism* / Q000473:pathology; D014057:Tomography, X-Ray Computed
chemical_list: D019788:Fluorodeoxyglucose F18