title: Follistatin is a novel biomarker for lung adenocarcinoma in humans.
abstract: BACKGROUND
  Follistatin (FST), a single chain glycoprotein, is originally isolated from follicular fluid of ovary. Previous studies have revealed that serum FST served as a biomarker for pregnancy and ovarian mucinous tumor. However, whether FST can serve as a biomarker for diagnosis in lung adenocarcinoma of humans remains unclear.
  
  
  RESULTS
  The study population consisted of 80 patients with lung adenocarcinoma, 40 patients with ovarian adenocarcinoma and 80 healthy subjects. Serum FST levels in patients and healthy subjects were measured using ELISA. The results showed that the positive ratio of serum FST levels was 51.3% (41/80), which was comparable to the sensitivity of FST in 40 patients with ovarian adenocarcinoma (60%, 24/40) using the 95th confidence interval for the healthy subject group as the cut-off value. FST expressions in lung adenocarcinoma were examined by immunohistochemical staining, we found that lung adenocarcinoma could produce FST and there was positive correlation between the level of FST expression and the differential degree of lung adenocarcinoma. Furthermore, the results showed that primary cultured lung adenocarcinoma cells could secrete FST, while cells derived from non-tumor lung tissues almost did not produce FST. In addition, the results of CCK8 assay and flow cytometry showed that using anti-FST monoclonal antibody to neutralize endogenous FST significantly augmented activin A-induced lung adenocarcinoma cells apoptosis.
  
  
  CONCLUSIONS
  These data indicate that lung adenocarcinoma cells can secret FST into serum, which may be beneficial to the survival of adenocarcinoma cells by neutralizing activin A action. Thus, FST can serve as a promising biomarker for diagnosis of lung adenocarcinoma and a useful biotherapy target for lung adenocarcinoma.
authors.affiliation: Department of Gastrointestinal Surgery, China-Japan Union Hospital, Jilin University, Changchun, China.
authors.forename: Fangfang
authors.initials: F
authors.lastname: Chen
authors.affiliation: Department of Thoracic Surgery, First Hospital of Jilin University, Changchun, China.
authors.forename: Ping
authors.initials: P
authors.lastname: Ren
authors.affiliation: Department of Gastrointestinal Surgery, China-Japan Union Hospital, Jilin University, Changchun, China.
authors.forename: Ye
authors.initials: Y
authors.lastname: Feng
authors.affiliation: Department of Immunology, College of Basic Medical Sciences, Jilin University, Changchun, China.
authors.forename: Haiyan
authors.initials: H
authors.lastname: Liu
authors.affiliation: Department of Immunology, College of Basic Medical Sciences, Jilin University, Changchun, China.
authors.forename: Yang
authors.initials: Y
authors.lastname: Sun
authors.affiliation: Department of Immunology, College of Basic Medical Sciences, Jilin University, Changchun, China.
authors.forename: Zhonghui
authors.initials: Z
authors.lastname: Liu
authors.affiliation: Department of Immunology, College of Basic Medical Sciences, Jilin University, Changchun, China.
authors.forename: Jingyan
authors.initials: J
authors.lastname: Ge
authors.affiliation: Department of Immunology, College of Basic Medical Sciences, Jilin University, Changchun, China.
authors.forename: Xueling
authors.initials: X
authors.lastname: Cui
mesh_terms: D000230:Adenocarcinoma / Q000097:blood*; D000328:Adult; D000368:Aged; D014408:Biomarkers, Tumor / Q000097:blood*; D016022:Case-Control Studies; D005260:Female; D038681:Follistatin / Q000097:blood*; D006801:Humans; D008175:Lung Neoplasms / Q000097:blood*; D008297:Male; D008875:Middle Aged
chemical_list: D014408:Biomarkers, Tumor; D038681:Follistatin