title: Association of thymidylate synthase expression and clinical outcomes of gastric cancer patients treated with fluoropyrimidine-based chemotherapy: a meta-analysis.
abstract: OBJECTIVE
  Although several studies have suggested an association between thymidylate synthase (TS) expression and outcomes of gastric cancer (GC) patients treated with fluoropyrimidine-based chemotherapy (FUC), the predictive value of TS for response and survival in this setting is unclear. This meta-analysis aimed to estimate prognostic and predictive significance of TS more precisely.
  
  
  METHODS
  We searched PubMed, Embase, Cochrane Library, and Web of Science databases for literature published up to June 2015. Primary outcomes included hazard ratios (HRs) for overall survival (OS), and event-free survival (EFS) and odds ratio (OR) for chemotherapy response. Fixed- or random-effects models were used to calculate pooled HR and OR according to heterogeneity.
  
  
  RESULTS
  A total of 2,442 GC patients in 25 studies met our inclusion criteria. Response rates for FUC were significantly lower in patients with high TS expression than in those with low expression (OR: 0.43, 95% confidence interval [CI]: 0.22-0.84, P=0.013). High TS expression was significantly correlated with unfavorable OS (HR: 1.62, 95% CI: 1.28-2.05, P<0.001) and EFS (HR: 1.54, 95% CI: 1.22-1.93, P<0.001) in advanced disease. However, TS expression was not significantly related to OS (HR: 1.06, 95% CI: 0.74-1.50, P=0.760) or EFS (HR: 1.16, 95% CI: 0.84-1.61, P=0.374) in the adjuvant setting.
  
  
  CONCLUSIONS
  Higher TS expression might predict drug resistance and adverse prognosis in patients with advanced GC treated with FUC.
authors.affiliation: Department of General Surgery, Chinese People's Liberation Army General Hospital, Beijing, People's Republic of China.
authors.forename: Yunhe
authors.initials: Y
authors.lastname: Gao
authors.affiliation: Department of General Surgery, Chinese People's Liberation Army General Hospital, Beijing, People's Republic of China.
authors.forename: Jianxin
authors.initials: J
authors.lastname: Cui
authors.affiliation: Department of General Surgery, Chinese People's Liberation Army General Hospital, Beijing, People's Republic of China.
authors.forename: Hongqing
authors.initials: H
authors.lastname: Xi
authors.affiliation: Department of General Surgery, Chinese People's Liberation Army General Hospital, Beijing, People's Republic of China.
authors.forename: Aizhen
authors.initials: A
authors.lastname: Cai
authors.affiliation: Department of General Surgery, Chinese People's Liberation Army General Hospital, Beijing, People's Republic of China.
authors.forename: Weisong
authors.initials: W
authors.lastname: Shen
authors.affiliation: Department of General Surgery, Chinese People's Liberation Army General Hospital, Beijing, People's Republic of China.
authors.forename: Jiyang
authors.initials: J
authors.lastname: Li
authors.affiliation: Department of General Surgery, Chinese People's Liberation Army General Hospital, Beijing, People's Republic of China.
authors.forename: Kecheng
authors.initials: K
authors.lastname: Zhang
authors.affiliation: Department of General Surgery, Chinese People's Liberation Army General Hospital, Beijing, People's Republic of China.
authors.forename: Bo
authors.initials: B
authors.lastname: Wei
authors.affiliation: Department of General Surgery, Chinese People's Liberation Army General Hospital, Beijing, People's Republic of China.
authors.forename: Lin
authors.initials: L
authors.lastname: Chen
keywords: clinical outcomes; fluoropyrimidine-based chemotherapy; gastric cancer; meta-analysis; thymidylate synthase