title: Non-FDG-avid primary papillary thyroid carcinoma may not differ from FDG-avid papillary thyroid carcinoma.
abstract: BACKGROUND
  FDG (2-[(18)F]Fluoro-2-D-deoxyglucose-positron emission tomography (PET)/computed tomography (CT), which can detect a change in glucose metabolism in cancer cells, has been introduced as a diagnostic and prognostic tool in papillary thyroid carcinoma (PTC). However, differences in the clinicopathological and biological characteristics between primary PTCs with FDG uptake and those without FDG uptake are not well established.
  
  
  METHODS
  A total of 188 patients with PTC who had preoperative PET/CT scans were enrolled to compare the differences of clinicopathological parameters between FDG-avid (F-PTC; n = 150) and non-FDG-avid tumors (FN-PTC; n = 38). Immunohistochemical staining for glucose transporter (GLUT)-1 and hypoxia-inducible factor-1 alpha (HIF-1α) was performed.
  
  
  RESULTS
  FN-PTCs were smaller; had a lower incidence of lymphatic invasion, vascular invasion, multifocality, and central lymph node metastasis; and had a lower maximum standardized uptake value than F-PTCs. After exclusion of high-risk patients for recurrence, FN-PTCs remained smaller (p < 0.001) and had less lymphatic invasion (p = 0.061). Among tumors larger than the spatial resolution of the PET/CT scan, macrocalcification was more frequent in FN-PTC than in F-PTC (p = 0.043). While FN-PTC and F-PTC showed no difference in GLUT-1 expression (50% vs. 75%, p = 0.363), FN-PTC showed lower HIF-1α immunoreactivity than F-PTC (25.0% vs. 75.0%, p = 0.032).
  
  
  CONCLUSIONS
  Tumor size and macrocalcification are clinicopathological differences between FN-PTC and F-PTC. Biologically, HIF-1α may be responsible for increased FDG uptake in PTC.
authors.affiliation: 1 Department of Internal Medicine (Division of Endocrinology and Metabolism), The Catholic University of Korea , College of Medicine, Seoul, Korea.
authors.forename: Min-Hee
authors.initials: MH
authors.lastname: Kim
authors.forename: Sun Hee
authors.initials: SH
authors.lastname: Ko
authors.forename: Ja-Seong
authors.initials: JS
authors.lastname: Bae
authors.forename: Sung-Hak
authors.initials: SH
authors.lastname: Lee
authors.forename: Chan-Kwon
authors.initials: CK
authors.lastname: Jung
authors.forename: Dong-Jun
authors.initials: DJ
authors.lastname: Lim
authors.forename: Ki-Hyun
authors.initials: KH
authors.lastname: Baek
authors.forename: Sung-Hoon
authors.initials: SH
authors.lastname: Kim
authors.forename: Jong-Min
authors.initials: JM
authors.lastname: Lee
authors.forename: Moo-Il
authors.initials: MI
authors.lastname: Kang
authors.forename: Bong-Yun
authors.initials: BY
authors.lastname: Cha
mesh_terms: D000328:Adult; D000368:Aged; D002277:Carcinoma / Q000145:classification* / Q000175:diagnosis / Q000000981:diagnostic imaging*; D002291:Carcinoma, Papillary; D005260:Female; D019788:Fluorodeoxyglucose F18; D005947:Glucose / Q000493:pharmacokinetics; D051272:Glucose Transporter Type 1 / Q000378:metabolism; D006801:Humans; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000378:metabolism; D007150:Immunohistochemistry; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D064847:Multimodal Imaging; D009154:Mutation; D009364:Neoplasm Recurrence, Local / Q000175:diagnosis; D049268:Positron-Emission Tomography; D048493:Proto-Oncogene Proteins B-raf / Q000235:genetics; D019275:Radiopharmaceuticals; D000077273:Thyroid Cancer, Papillary; D013964:Thyroid Neoplasms / Q000145:classification* / Q000175:diagnosis / Q000000981:diagnostic imaging*; D014057:Tomography, X-Ray Computed
chemical_list: D051272:Glucose Transporter Type 1; C497442:HIF1A protein, human; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D019275:Radiopharmaceuticals; C495677:SLC2A1 protein, human; D019788:Fluorodeoxyglucose F18; C482119:BRAF protein, human; D048493:Proto-Oncogene Proteins B-raf; D005947:Glucose