MTOR PATHWAY PROTEIN IMMUNOEXPRESSION AS A PROGNOSTIC FACTOR FOR SURVIVAL IN HNC: A SYSTEMATIC REVIEW AND META-ANALYSIS

Abstract

Activated proteins in the mTOR pathway are deregulated in multiple types of cancer. These proteins may be important targets for anticancer therapy. The aim of this study was to summarize existing cohort studies to determine whether immunoexpression of mTOR pathway proteins are important prognostic factors for survival in head and neck cancer (HNC) patients. A systematic review was performed using the Cochrane, Lilacs, PubMed, ScienceDirect, Scopus and Web of Science databases (up to 23 January 2015). A meta-analysis was conducted to measure the frequency of protein expression in HNC patient samples and the prognostic value of mTOR pathway proteins for overall survival (OS) and disease-free survival (DFS). 12 studies were included in the final analysis. The meta-analysis revealed that the frequency of overall expression of mTOR pathway proteins was 74.42% (CI: 63.3 to 84.0, P < 0,001, n=2,016 samples). The survival meta-analysis showed a pooled hazard ratio for OS and DFS of 1.44 (95% confidence interval [95% CI] 1.14-1.73) and 1.18 (95% CI 0.71-1.64), respectively. This systematic review and meta-analysis support evidence that mTOR pathway proteins can be used as predictive markers for survival in HNC patients because their expression was significantly associated with poor OS and short DFS.