NANOG and brain neoplasm: In addition to octamer‐binding transcription factor 4 (OCT4), SOX2, Nanog homeobox (Nanog), proto‐oncogene, bHLH transcription factor (c‐MYC), and KLF transcription factor 4 (KLF4), which are well‐known regulators of CSCs, some of the less‐studied transcription factors have also been reported to have a role in the maintenance of stem cell‐like features in brain tumor.