title: Investigation of salivary free amino acid profile for early diagnosis of breast cancer with ultra performance liquid chromatography-mass spectrometry.
abstract: BACKGROUND
  Breast cancer (BC) is the second leading cause of cancer death in women worldwide. This study aimed at investigating salivary free amino acid (SFAA) profile to facilitate the early diagnosis of BC.
  
  
  METHODS
  Unstimulated whole saliva from BC patients (n=27) and randomly from healthy females (n=28) were assayed with ultra-performance liquid chromatography-mass spectrometry (UPLC-MS). Receiver operating characteristic curve (ROC) was used to evaluate the diagnostic performance of each of the amino acid (AA) biomarkers, or SFAA profile index for BC screening.
  
  
  RESULTS
  Concentrations of 15 SFAAs demonstrated significant differences (P<0.05) between BC patients at stages I-II and healthy controls (HC). The area under the curve (AUC) values in HC vs BCs I-II based on single AA were from 0.695 to 0.866. The AUC for SFAA profile index combined Pro, Thr, His was 0.916 (sensitivity 88.2%, specificity 85.7%) in distinguishing HC from BCs I-II.
  
  
  CONCLUSIONS
  The diagnostic potentials of 15 SFAAs as early diagnostic biomarkers for BC were verified and the diagnostic accuracy was improved in the use of SFAA profile index. The detection of SFAA profile is expected to be applied for the preclinical screening of early stage of BC in the future.
authors.affiliation: Research Center of Analytical Instrumentation, Analytical & Testing Centre, Sichuan University, Chengdu 610064, China.
authors.forename: Fei
authors.initials: F
authors.lastname: Cheng
authors.affiliation: West China Medicine College, Sichuan University, Chengdu 610041, China.
authors.forename: Zhenwu
authors.initials: Z
authors.lastname: Wang
authors.affiliation: Research Center of Analytical Instrumentation, Key Laboratory of Bio-resource and Eco-environment, Ministry of Education, College of Life Science, Sichuan University, Chengdu 610041, China; College of Chemistry, Sichuan University, Chengdu 610064, China.
authors.forename: Yanping
authors.initials: Y
authors.lastname: Huang
authors.affiliation: Research Center of Analytical Instrumentation, Key Laboratory of Bio-resource and Eco-environment, Ministry of Education, College of Life Science, Sichuan University, Chengdu 610041, China. Electronic address: yduan@scu.edu.cn.
authors.forename: Yixiang
authors.initials: Y
authors.lastname: Duan
authors.affiliation: Department of Breast Surgery, West China Hospital, Sichuan University, Chengdu 610064, China. Electronic address: wxd65112@163.com.
authors.forename: Xiaodong
authors.initials: X
authors.lastname: Wang
mesh_terms: D000328:Adult; D000368:Aged; D000596:Amino Acids / Q000032:analysis*; D001943:Breast Neoplasms / Q000175:diagnosis*; D016022:Case-Control Studies; D002851:Chromatography, High Pressure Liquid; D055088:Early Detection of Cancer / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D013058:Mass Spectrometry; D008875:Middle Aged; D012372:ROC Curve; D015203:Reproducibility of Results; D012463:Saliva / Q000737:chemistry*
chemical_list: D000596:Amino Acids
keywords: Amino acid profile; Biomarker; Breast cancer; Early diagnosis; Saliva