title: Elevated serum annexin A1 as potential diagnostic marker for lung cancer: a retrospective case-control study.
abstract: BACKGROUND
  Annexin A1 was investigated as prognostic factor because of its apparent association with tumorigenesis. The aim of this study was to investigate the expression of annexin A1 in lung cancer patients, and analysed the relationship with respect to the clinico-pathological features and assessed whether annexin A1 as a potential serum marker for lung cancer.
  
  
  METHODS
  Expression of annexin A1 was examined using immunohistochemistry, in-situ hybridization, western blot and enzyme-linked immunosorbent assay. Sensitivities and specificities for annexin A1 serum test were determined using receiver operator characteristic curve and cutoff was defined based on 95% and 85% sensitivities.
  
  
  RESULTS
  Lung cancer tissues exhibited higher expression of annexin A1 than the normal tissues (P < 0.05) and the serum annexin A1 of lung cancer patients also exhibited higher level than control groups (P < 0.05). Moreover, increased serum annexin A1 was significantly associated with the pathological grade and clinical stage of lung cancer patients (P < 0.05). Using receiver operator characteristic curve analysis, the cutoffs for distinguishing lung cancer from normal and benign groups were 4.77 and 4.84 ng/ml respectively. The sensitivities of annexin A1 for distinguishing lung cancer from normal and benign groups were 98.9% and 97.4%, and specificities were 88.3% and 66.4%.
  
  
  CONCLUSIONS
  Up-regulation of serum annexin A1 was associated with pathological grade and clinical stage of lung cancer patients, which indicated that it could be considered molecular biomarker for diagnosis and prognosis of lung cancer.
authors.affiliation: Department of Respiratory Medicine, Second Affiliated Hospital, Xi'an Jiaotong University Xi'an, China.
authors.forename: Biaoxue
authors.initials: B
authors.lastname: Rong
authors.affiliation: Department of Neurology, Lanzhou University Second Hospital Lanzhou, China.
authors.forename: Chongchong
authors.initials: C
authors.lastname: Zhao
authors.affiliation: Department of Respiratory Medicine, Gansu Provincial People's Hospital Lanzhou, China.
authors.forename: Hua
authors.initials: H
authors.lastname: Liu
authors.affiliation: Department of Respiratory Medicine, Second Affiliated Hospital, Xi'an Jiaotong University Xi'an, China.
authors.forename: Zongjuan
authors.initials: Z
authors.lastname: Ming
authors.affiliation: Department of Respiratory Medicine, Gansu Provincial People's Hospital Lanzhou, China.
authors.forename: Xiguang
authors.initials: X
authors.lastname: Cai
authors.affiliation: Department of Statistics and Epidemiology, Medical College, Lanzhou University Lanzhou, China.
authors.forename: Wenlong
authors.initials: W
authors.lastname: Gao
authors.affiliation: Department of Respiratory Medicine, Second Affiliated Hospital, Xi'an Jiaotong University Xi'an, China.
authors.forename: Shuanying
authors.initials: S
authors.lastname: Yang
keywords: Lung cancer; annexin A1; biomarker; diagnosis; serum