Overexpression of Nanog protein is associated with poor prognosis in gastric adenocarcinoma

Nanog, a key transcription factor in self-renewal and pluripotency of embryonic stem cells, has been proved to play a novel role in solid tumor development. Here, we investigated Nanog protein expression in retrospective clinical samples of 105 patients underwent resective surgery for gastric adenocarcinoma. We found that Nanog protein immunostaining in tumor tissues was stronger than that in their corresponding non-dysplastic tissues. However, no statistical difference of Nanog protein expression between tumor tissues and metastatic lymph nodes was found (P = 0.143). Interestingly, overexpression of Nanog protein was correlated with advanced clinical stage of patients with gastric adenocarcinoma (P = 0.006). And Nanog protein expression was correlated with lymph node status (P = 0.004), infiltrating extent (P = 0.001), and differentiation (P = 0.000) of patients with gastric adenocarcinoma. Survival analysis showed that overexpression of Nanog protein in gastric cancer patients predicted a poorer prognosis (P = 0.000). Our data first demonstrated a potential diagnostic and prognostic role of Nanog for gastric adenocarcinoma.