title: Relationship between circulating anti-thyroglobulin antibodies (TgAb) and tumor metabolism in patients with differentiated thyroid cancer (DTC): prognostic implications.
abstract: OBJECTIVE
  TgAb have been proposed as tumor markers in DTC. Recent evidence links TgAb levels with DTC aggressiveness. We aimed to evaluate the relationship between TgAb and tumor glucose metabolism in DTC patients.
  
  
  METHODS
  Seventy-one DTC patients who underwent18F-FDG PET/CT were included. According to TgAb value and trends, patients were divided into TgAb positive (TgAb+) or negative (TgAb-) as well as in patients with increasing (Inc-TgAb) or decreasing (Dec-TgAb) trend. On the basis of the results of FDG-PET, post-therapy 131I and Tg levels, patients were divided into two groups according to the evidence (ED) or absence (NED) of disease. ED patients were further divided into three subgroups: 1. radioiodine avid with positive18F-FDG PET/CT (PET+/131I+), 2. radioiodine refractory with positive18F-FDG PET/CT (PET+/131I-) and 3. radioiodine avid with negative18F-FDG PET/CT (PET-/131I+). MeanSUV of FDG-avid lesions was assessed and averaged for each patient (SUVmean-pt). T test was performed to assess the difference between SUVmean in TgAb-, TgAb+ and in Inc-TgAb and Dec-TgAb subgroups. Difference in TgAb between ED and NED patients as well as between ED patients and PET+/131I+, PET+/131I- and PET-/131I+ subgroups was compared.
  
  
  RESULTS
  SUVmean was significantly higher in Inc-TgAb with respect to Dec-TgAb subgroup (5.2 ± 1.5 vs. 2.9 ± 1.1, p < 0.05). TgAb were higher only in the ED PET+/131I+ subgroup with respect to NED patients (p < 0.01).
  
  
  CONCLUSIONS
  The relationship between higher tumor metabolism and trend of TgAb supports a prognostic relevance of TgAb in DTC patients. Significantly higher TgAb in radioiodine avid tumors with positive18F-FDG PET/CT further testify the role of TgAb as surrogate tumor marker in DTC.
authors.affiliation: Nuclear Medicine UnitIRCCS AOU San Martino - IST, University of Genoa, Largo R. Benzi 10, 16132, Genoa, Italy. Silviadaniela.morbelli@hsanmartino.it.|Thyroid Cancer Board, IRCCS AOU San Martino - IST, University of Genoa, Genoa, Italy. Silviadaniela.morbelli@hsanmartino.it.
authors.forename: S
authors.initials: S
authors.lastname: Morbelli
authors.affiliation: Nuclear Medicine UnitIRCCS AOU San Martino - IST, University of Genoa, Largo R. Benzi 10, 16132, Genoa, Italy.
authors.forename: G
authors.initials: G
authors.lastname: Ferrarazzo
authors.affiliation: Nuclear Medicine UnitIRCCS AOU San Martino - IST, University of Genoa, Largo R. Benzi 10, 16132, Genoa, Italy.|Thyroid Cancer Board, IRCCS AOU San Martino - IST, University of Genoa, Genoa, Italy.
authors.forename: E
authors.initials: E
authors.lastname: Pomposelli
authors.affiliation: Autoimmunity UnitIRCCS AOU San Martino - IST, University of Genoa, Genoa, Italy.
authors.forename: F
authors.initials: F
authors.lastname: Pupo
authors.affiliation: Autoimmunity UnitIRCCS AOU San Martino - IST, University of Genoa, Genoa, Italy.
authors.forename: G
authors.initials: G
authors.lastname: Pesce
authors.affiliation: Nuclear Medicine UnitIRCCS AOU San Martino - IST, University of Genoa, Largo R. Benzi 10, 16132, Genoa, Italy.
authors.forename: I
authors.initials: I
authors.lastname: Calamia
authors.affiliation: Nuclear Medicine UnitIRCCS AOU San Martino - IST, University of Genoa, Largo R. Benzi 10, 16132, Genoa, Italy.
authors.forename: F
authors.initials: F
authors.lastname: Fiz
authors.affiliation: Autoimmunity UnitIRCCS AOU San Martino - IST, University of Genoa, Genoa, Italy.
authors.forename: A
authors.initials: A
authors.lastname: Clapasson
authors.affiliation: Nuclear Medicine UnitIRCCS AOU San Martino - IST, University of Genoa, Largo R. Benzi 10, 16132, Genoa, Italy.
authors.forename: M
authors.initials: M
authors.lastname: Bauckneht
authors.affiliation: U.O. Chirurgia 1, Department of Surgery, IRCCS AOU San Martino - IST, Genoa, Italy.|Department of Surgical Sciences (DISC), University of Genoa, Genoa, Italy.|Thyroid Cancer Board, IRCCS AOU San Martino - IST, University of Genoa, Genoa, Italy.
authors.forename: M
authors.initials: M
authors.lastname: Minuto
authors.affiliation: Nuclear Medicine UnitIRCCS AOU San Martino - IST, University of Genoa, Largo R. Benzi 10, 16132, Genoa, Italy.
authors.forename: G
authors.initials: G
authors.lastname: Sambuceti
authors.affiliation: Endocrinology UnitIRCCS AOU San Martino - IST, University of Genoa, Genoa, Italy.|Thyroid Cancer Board, IRCCS AOU San Martino - IST, University of Genoa, Genoa, Italy.
authors.forename: M
authors.initials: M
authors.lastname: Giusti
authors.affiliation: Autoimmunity UnitIRCCS AOU San Martino - IST, University of Genoa, Genoa, Italy.|Thyroid Cancer Board, IRCCS AOU San Martino - IST, University of Genoa, Genoa, Italy.
authors.forename: M
authors.initials: M
authors.lastname: Bagnasco
mesh_terms: D000230:Adenocarcinoma / Q000276:immunology / Q000378:metabolism / Q000556:secondary*; D018263:Adenocarcinoma, Follicular / Q000276:immunology / Q000378:metabolism / Q000556:secondary*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001323:Autoantibodies / Q000097:blood*; D014408:Biomarkers, Tumor / Q000097:blood*; D002291:Carcinoma, Papillary / Q000276:immunology / Q000378:metabolism / Q000556:secondary*; D005260:Female; D019788:Fluorodeoxyglucose F18 / Q000378:metabolism; D006801:Humans; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D000072078:Positron Emission Tomography Computed Tomography; D011379:Prognosis; D013954:Thyroglobulin / Q000276:immunology; D013964:Thyroid Neoplasms / Q000276:immunology / Q000378:metabolism / Q000473:pathology*; D051598:Whole Body Imaging / Q000379:methods*; D055815:Young Adult
chemical_list: D001323:Autoantibodies; D014408:Biomarkers, Tumor; C006606:anti-thyroglobulin; D019788:Fluorodeoxyglucose F18; D013954:Thyroglobulin
keywords: Anti-thyroglobulin autoantibodies; Positron emission tomography; Thyroglobulin; Thyroid Cancer