Prognostic Value of Phosphorylated mTOR/RPS6KB1 in Nonsmall Cell Lung Cancer

Background: The mammalian target of rapamycin (mTOR) /RPS6KB1 activation has recently been implicatedin tumour development, but its role in lung cancer remains unclear. The aim of this study was to explore the roleof mTOR/RPS6KB1 signaling pathway in non-small-cell lung cancer (NSCLC).
Methods: Immunohistochemistrywas performed to assess the expression of phosphorylated mammalian target of rapamycin (p-mTOR) and itsdownstream ribosomal phosphorylated RPS6KB1 (p-RPS6KB1) in NSCLC patients. We also analyzed p-mTOR/p-RPS6KB1 protein expression in 45 fresh NSCLC tissues using Western blotting.
Results: The expressionlevel of p-mTOR and p-RPS6KB1 was significantly higher in NSCLC tumor specimens than that in adjacentnoncancerous normal lung tissues (P<0.01). p-mTOR expression correlated with p-RPS6KB1. Furthermore,high expression level of p-mTOR or p-RPS6KB1 in NSCLC was associated with a shorter overall survival (bothP<0.01). Multivariate analysis indicated high level of p-mTOR expression was an independent prognostic factor(HR=2.642, 95%CI 1.157–4.904, p=0.002).
Conclusions: p-mTOR and p-RPS6KB1 could be useful prognosticmarkers for NSCLC.