title: Thyroglobulin antibody is associated with increased cancer risk in thyroid nodules.
abstract: BACKGROUND
  The association between autoimmune thyroiditis (AIT) and thyroid cancer is still not clear despite many previous reports. This study investigated whether serologic thyroid antibodies are predictive of thyroid cancer in patients with thyroid nodules.
  
  
  METHODS
  We retrospectively reviewed records of patients with thyroid nodules evaluated by ultrasonography-guided fine-needle aspiration cytology at our institution between January 2006 and December 2008. Thyroid autoimmunity was assessed by measuring thyroglobulin antibody (TgAb) and thyroid peroxidase antibody (TPOAb). The final outcome deciding a benign or malignant status involved a combination of cytology and histology.
  
  
  RESULTS
  Of the 1638 patients, malignant nodules had a higher rate of positive TgAb (30.8% vs. 19.6%; p < 0.001) and elevated thyrotropin (TSH) levels (2.5 +/- 2.8 mIU/L vs. 2.1 +/- 2.0 mIU/L; p = 0.021) than benign nodules. The rate of positive TPOAb was not higher in malignant nodules, although both TPOAb and TgAb were well correlated with TSH levels and histological AIT. In the multivariate analysis, a positive TgAb was significantly associated with thyroid cancer (odds ratio [OR] = 1.61, 95% confidence interval [CI] 1.12-2.33) with upper tertile of normal range of TSH levels (OR = 1.72, 95% CI 1.12-2.63) and above normal range of TSH levels (OR = 1.98, 95% CI 1.06-3.70).
  
  
  CONCLUSIONS
  We report for the first time that a positive serum TgAb test was an independent predictor for thyroid malignancy in thyroid nodules along with serum TSH levels regardless of the presence of AIT. Our results suggest that TgAb measurement could give additional information for predicting malignancy in cytologically indeterminate thyroid nodules in conjunction with clinical risk factors and TSH levels.
authors.affiliation: Division of Endocrinology and Metabolism, Department of Internal medicine, The Catholic University of Korea College of Medicine , Seoul, Korea.
authors.forename: Eun Sook
authors.initials: ES
authors.lastname: Kim
authors.forename: Dong Jun
authors.initials: DJ
authors.lastname: Lim
authors.forename: Ki Hyun
authors.initials: KH
authors.lastname: Baek
authors.forename: Jong Min
authors.initials: JM
authors.lastname: Lee
authors.forename: Mee Kyoung
authors.initials: MK
authors.lastname: Kim
authors.forename: Hyuk Sang
authors.initials: HS
authors.lastname: Kwon
authors.forename: Ki Ho
authors.initials: KH
authors.lastname: Song
authors.forename: Moo Ii
authors.initials: MI
authors.lastname: Kang
authors.forename: Bong Yun
authors.initials: BY
authors.lastname: Cha
authors.forename: Kwang Woo
authors.initials: KW
authors.lastname: Lee
authors.forename: Ho Young
authors.initials: HY
authors.lastname: Son
mesh_terms: D000328:Adult; D000368:Aged; D000906:Antibodies / Q000737:chemistry*; D001323:Autoantibodies / Q000276:immunology*; D001327:Autoimmune Diseases / Q000276:immunology; D003584:Cytological Techniques; D005260:Female; D006801:Humans; D007453:Iodide Peroxidase / Q000737:chemistry / Q000276:immunology; D008297:Male; D008875:Middle Aged; D012307:Risk Factors; D013954:Thyroglobulin / Q000737:chemistry / Q000276:immunology*; D013961:Thyroid Gland / Q000276:immunology / Q000473:pathology*; D013964:Thyroid Neoplasms / Q000737:chemistry / Q000276:immunology*; D016606:Thyroid Nodule / Q000737:chemistry / Q000276:immunology*
chemical_list: D000906:Antibodies; D001323:Autoantibodies; C006606:anti-thyroglobulin; D013954:Thyroglobulin; D007453:Iodide Peroxidase