Oct4high cells have more SC-like traits, such as self-renewal, chemoresistance and xenograft tumorigenicity, than Oct4low cells.57 To date, Oct4 has been used to isolate CSCs by Oct4 promoter-mediated activity in breast cancer,58 non-small cell lung cancer (NSCLC),59 gastric cancer60 and HCC.61 The gene discussed is POU5F1; the disease is breast carcinoma.