title: Serum Unsaturated Free Fatty Acids: A Potential Biomarker Panel for Differentiating Benign Thyroid Diseases from Thyroid Cancer.
abstract: BACKGROUND
  Serum free fatty acids (FFAs) are correlated with pathological status, and change in serum FFA levels may be associated with thyroid diseases.
  
  
  METHODS
  In this study, 664 serum samples from 322 healthy controls, 129 patients with benign thyroid disease (BTD), and 213 patients with thyroid cancer (TC) were collected. Chip-based direct-infusion nanoelectrospray-mass spectrometry was performed to simultaneously quantify six serum FFAs (i.e., C16:1, C18:1, C18:2, C18:3, C20:4, and C22:6.), with the excellent correlation coefficients of > 0.99 and relative standard deviation of <18% for all analysts. The Mann-Whitney U test was used to compare the differences in serum FFA levels between three above-mentioned groups.
  
  
  RESULTS
  Significant increase in the levels of C16:1, C18:1, C18:2, C18:3, C20:4, and C22:6 in healthy controls relative to TC patients and BTD patients was observed, and the levels of C16:1, C18:2, C20:4, and C22:6 in BTD patients were significantly decreased relative to TC patients. Receiver operating characteristic (ROC) analysis indicated that a combination of C16:1, C18:2, C20:4, and C22:6 has excellent diagnostic performance to differentiate BTD patients from TC patients, with an area under the ROC curve of 0.857, a sensitivity of 76.8%, and a specificity of 83.7%.
  
  
  CONCLUSIONS
  Change in serum levels of FFAs is closely correlated with thyroid diseases, and a biomarker panel (C16:1, C18:2, C20:4, and C22:6) should be of benefit to differentiate BTD patients from TC patients.
authors.affiliation: 1. Department of Biophysics and Structural Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences & School of Basic Medicine, Peking Union Medical College, Beijing 100005, PR China.
authors.forename: Yaping
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: 2. Department of Clinical Laboratory, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100730, PR China.
authors.forename: Ling
authors.initials: L
authors.lastname: Qiu
authors.affiliation: 3. Clinical Lab Diagnosis, China-Japan Union Hospital, Jilin University, Changchun 130041, PR China.
authors.forename: Chengyan
authors.initials: C
authors.lastname: He
authors.affiliation: 4. Department of Clinical Laboratory, Heze Municipal Hospital, Shandong 1740031, PR China.
authors.forename: Yanmin
authors.initials: Y
authors.lastname: Wang
authors.affiliation: 1. Department of Biophysics and Structural Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences & School of Basic Medicine, Peking Union Medical College, Beijing 100005, PR China.
authors.forename: Yujie
authors.initials: Y
authors.lastname: Liu
authors.affiliation: 1. Department of Biophysics and Structural Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences & School of Basic Medicine, Peking Union Medical College, Beijing 100005, PR China.
authors.forename: Dan
authors.initials: D
authors.lastname: Zhang
authors.affiliation: 1. Department of Biophysics and Structural Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences & School of Basic Medicine, Peking Union Medical College, Beijing 100005, PR China.
authors.forename: Zhili
authors.initials: Z
authors.lastname: Li
keywords: biomarker panel; serum.; thyroid diseases; unsaturated free fatty acids