Prognostic Value of NRAS Gene for Survival of Colorectal Cancer Patients: A Systematic Review and Meta-Analysis

Abstract

Introduction: NRAS gene is associated with malignant proliferation and metastasis of colorectal cancer (CRC).<br />But its prognostic value on CRC is still unknown. The objective of this study is to perform a meta-analysis to obtain<br />its prognostic value on survival of CRC patients. Methods: The systematic review and meta-analysis was designed,<br />undertaken and reported using items from the PRISMA statement. Relevant articles were identified through PubMed<br />(containing Medline), Embase, Web of Science databases and Google scholar search engines from their inception up to<br />October 3, 2016. The articles about NRAS on prognosis of CRC patients were enrolled. The association between NRAS<br />and CRC survival time (including overall survival [OS], progression-free survival [PFS], and disease-free survival<br />[DFS]) was evaluated using hazard ratio (HR) with its corresponding 95% confidence interval (CI). Results: A total<br />of fifteen articles were included. High-expression of NRAS was significantly associated with poor OS (HR: 1.36, 95%<br />CI: 1.15–1.61), and poor PFS (HR: 1.75, 95% CI: 1.04–2.94). The combined HR of NRAS on DFS was 0.87 (95% CI:<br />0.37–2.03). Subgroup analysis showed that NRAS was significantly associated with poor OS for patients from Western<br />countries (HR: 1.38, 95% CI: 1.09–1.73), but not for those from Asian countries. Conclusions: This meta-analysis<br />demonstrate that NRAS gene could predict the poor prognosis for the CRC patients. More large-sample cohort studies<br />are needed to further confirm this conclusion.