Predictive and Prognostic Roles of Ribonucleotide Reductase M1 in Patients with Pancreatic Cancer Treated with Gemcitabine: A Meta-analysis

Increasing scientific evidence suggests that ribonucleotide reductase M1 (RRM1) may be a powerful predictorof survival in patients with pancreatic cancer treated with adjuvant gemcitabine-based chemotherapy afteroperative resection, but many existing studies have yielded inconclusive results. This meta-analysis aimedto assess the prognostic role of RRM1 in predicting survival in patients with pancreatic cancer treated withgemcitabine. An extensive literature search for relevant studies was conducted on PubMed, Embase, Web ofScience, Cochrane Library, and CBM databases from their inception through May 1st, 2013. This meta-analysiswas performed using the STATA 12.0 software and crude hazard ratios (HRs) with 95% confidence intervals(CIs) were calculated. Eight clinical studies were included in this meta-analysis with a total of 665 pancreaticcancer patients treated with adjuvant gemcitabine-based chemotherapy, including 373 patients in the high RRM1expression group and 292 patients in the low RRM1 expression group. Our meta-analysis revealed that highRRM1 expression was associated with improved overall survival (OS) of pancreatic cancer patients (HR=1.56,95%CI=0.95-2.17, P<0.001). High RRM1 expression also was linked to longer disease-free survival (DFS) thanlow RRM1 expression (HR=1.37, 95%CI=0.25-2.48, P=0.016). In conclusion, our meta-analysis suggests thathigh RRM1 expression may be associated with improved OS and DFS of pancreatic cancer patients treated withadjuvant gemcitabine-based chemotherapy. Detection of RRM1 expression may be a promising biomarker forgemcitabine response and prognosis in pancreatic cancer patients.