In recent years, SOX2 and OCT4 have been identified as biomarkers of CSCs, which regulate proliferation, maintenance of self-renewal capacity, and tumorigenicity, such as in glioblastoma tumor-initiating cells (34), HNSCCs (19) and esophageal squamous cell carcinomas (35). The gene discussed is POU5F1; the disease is esophageal squamous cell carcinoma.