Nanog is well known as the main stemness‐related transcription factor.8 Nanog is generally expressed in CSCs with different phenotypes, and thus, is now identified as the universal molecular feature of CSCs in different cancers.32, 33, 34 In our present study, the methylation status of the Nanog promoter CG5 site was identified as an indicator to mark the difference between CSCs and non‐CSCs. Here, NANOG is linked to cancer.