Oct4 was identified as the putative marker of oral cancer stem-like cells and played a pivotal role in the chemoresistance of CSCs derived from prostate cancer [18, 19]. Previous study showed that GC patients with negative expression of Oct4 had worse prognosis than those with positive expression ; however, other report showed that Oct4 was expressed higher in GC tissues than non-cancerous tissues and associated with poor differentiation . It was demonstrated that metastatic lesions had more Oct4 positive expression than negative expression .