title: The pemetrexed-containing treatments in the non-small cell lung cancer is -/low thymidylate synthase expression better than +/high thymidylate synthase expression: a meta-analysis.
abstract: BACKGROUND
  The predictive value of thymidylate synthase (TS) for clinical sensitivity to pemetrexed-containing chemotherapy in patients with non-small cell lung cancer (NSCLC) remains controversial. This meta-analysis is performed to provide an assessment of whether expression variations of TS are associated with objective response in patients with NSCLC treated with pemetrexed-containing chemotherapy.
  
  
  METHODS
  An electronic search was conducted using the databases MEDLINE, EMBASE and CNKI, from inception to June 10th, 2013. A systemic review of the studies on the association between TS expression in NSCLC and objective response of pemetrexed-containing regimen was performed. Pooled odds ratios (OR) for the response rate were calculated using the software Revman 5.0.
  
  
  RESULTS
  There were a total of 526 patients in the eight studies that met our criteria for evaluation. +/high expression of TS was found in 269 patients (51.1%), and -/low expression for this gene was found in 257 (48.9%) patients. The objective response rate for pemetrexed-containing chemotherapy was significantly higher in patients with -/low expression TS expression (OR = 0.45; 95% CI, 0.29-0.70; p = 0.0004). Although patients with -/low expression of TS have a longer median overall survival time and progression free survival time than those with +/high expression of TS, the difference was not statistically significant.
  
  
  CONCLUSIONS
  -/low expression of TS was associated with higher objective response in NSCLC patients treated with pemetrexed-containing chemotherapy. TS may be a suitable marker of sensitivity to pemetrexed-based chemotherapy in patients with NSCLC.
authors.forename: Lei
authors.initials: L
authors.lastname: Wang
authors.forename: Rui
authors.initials: R
authors.lastname: Wang
authors.forename: Yunjian
authors.initials: Y
authors.lastname: Pan
authors.forename: Yihua
authors.initials: Y
authors.lastname: Sun
authors.affiliation: Department of Thoracic Surgery, Shanghai Medical College, Fudan University Shanghai Cancer Center, 270 Dong-An Road, Shanghai 200032, China. zhangjie2289@hotmail.com.
authors.forename: Jie
authors.initials: J
authors.lastname: Zhang
authors.forename: Haiquan
authors.initials: H
authors.lastname: Chen
mesh_terms: D000964:Antimetabolites, Antineoplastic / Q000627:therapeutic use*; D014408:Biomarkers, Tumor / Q000096:biosynthesis / Q000235:genetics; D002289:Carcinoma, Non-Small-Cell Lung / Q000188:drug therapy* / Q000201:enzymology*; D015972:Gene Expression Regulation, Neoplastic; D005971:Glutamates / Q000627:therapeutic use*; D006147:Guanine / Q000031:analogs & derivatives* / Q000627:therapeutic use; D006801:Humans; D008175:Lung Neoplasms / Q000188:drug therapy / Q000201:enzymology*; D000068437:Pemetrexed; D013940:Thymidylate Synthase / Q000096:biosynthesis* / Q000235:genetics*; D016896:Treatment Outcome
chemical_list: D000964:Antimetabolites, Antineoplastic; D014408:Biomarkers, Tumor; D005971:Glutamates; D000068437:Pemetrexed; D006147:Guanine; D013940:Thymidylate Synthase