Available formalin-fixed paraffin-embedded primary lesions (n=377) and metastatic LNs (n=194) of patients with GC in Department of Gastrointestinal Surgery, West China Hospital, Sichuan University from January 2006 to October 2012 were retrospectively enrolled for CD54, Lgr5, Oct4, CD133 and EpCAM tests through IHC. For Sox2, available formalin-fixed paraffin-embedded primary lesions (n=307) and metastatic LNs (n=184) were collected from January 2007 to October 2012. We also collected 93 pairs of primary lesions and corresponding adjacent normal gastric tissues stored in liquid nitrogen of patients with GC from December 2011 to October 2012 to perform qPCR. The primary lesions of these 93 patients had also been tested by IHC. All patients were followed up through telephones, mails and outpatient visits up to January 2015. The clinicopathological characteristics and follow-up details were collected. The West China Hospital research ethics committee approved retrospective analysis of anonymous data. Signed patient informed consent was waived per the committee approval, because it was a retrospective analysis. The flow chart of the patients was shown in Figure 13.