title: RRM1 expression is associated with the outcome of gemcitabine-based treatment of non-small cell lung cancer patients--a short report.
abstract: OBJECTIVE
  RRM1 is the large subunit of ribonucleotide reductase (RNR), which catalyzes the rate-limiting step in the production of deoxyribonucleotides (dNTPs) and is essential for DNA synthesis and repair. Through a meta-analysis of observational studies, we evaluated whether RRM1 expression levels are associated with the clinical outcome of gemcitabine-containing treatment regimens in patients with advanced non-small cell lung cancer (NSCLC).
  
  
  METHODS
  A literature search was conducted using the PubMed, Embase, Web of Science, Wanfang and Chinese National Knowledge Infrastructure databases from inception to September 2014. A meta-analysis was conducted to pool eligible studies, and pooled analyses were performed using fixed effects models.
  
  
  RESULTS
  A total of 12 studies encompassing 593 NSCLC patients met our search criteria and were, therefore, included. Pooled analyses revealed that patients with low/negative RRM1 expression levels exhibited significantly higher response rates (OR: 0.35, 95 % CI 0.24-0.51) and better survival rates (OR: 0.41, 95 % CI 0.23-0.75) than those with high/positive RRM1 expression levels. Subgroup analyses did not reveal any significant heterogeneity in outcome regarding the RRM1 assessment methods used or the ethnicities of patient populations studied.
  
  
  CONCLUSIONS
  The meta-analysis reported here indicates that RRM1 expression is associated with the response rate and overall survival rate of advanced NSCLC patients treated with gemcitabine-based chemotherapy. Additional phase III randomized trials are required to confirm our current findings.
authors.affiliation: The Second Affiliated Hospital, Department of Oncology, Chongqing Medical University, NO.74, Linjiang road, Yuzhong district, Chongqing, China.
authors.forename: Chuan
authors.initials: C
authors.lastname: Zeng
authors.forename: Weidong
authors.initials: W
authors.lastname: Fan
authors.forename: Xianquan
authors.initials: X
authors.lastname: Zhang
mesh_terms: D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use*; D002289:Carcinoma, Non-Small-Cell Lung / Q000188:drug therapy* / Q000235:genetics / Q000378:metabolism; D003841:Deoxycytidine / Q000008:administration & dosage / Q000031:analogs & derivatives; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D007150:Immunohistochemistry; D008175:Lung Neoplasms / Q000188:drug therapy* / Q000235:genetics / Q000378:metabolism; D011379:Prognosis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012262:Ribonucleoside Diphosphate Reductase; D016019:Survival Analysis; D016896:Treatment Outcome; D025521:Tumor Suppressor Proteins / Q000235:genetics* / Q000378:metabolism; D000093542:Gemcitabine
chemical_list: D025521:Tumor Suppressor Proteins; D003841:Deoxycytidine; C475286:RRM1 protein, human; D012262:Ribonucleoside Diphosphate Reductase; D000093542:Gemcitabine