KLF4 and neuroblastoma: The common hypoxic 5hmC gain set of all NB cell lines included the genes of various epigenetic or chromatin remodeling enzymes (DNMT3A, DNMT3L, KDM4B, KDM6B, HDAC4, etc.)and proteins regulating development (NOTCH and WNT pathway proteins, the members of SOX, PAX, KLF families, including the pluripotency maintaining factors, SOX2 and KLF4) (Supplementary Table 2), suggesting that hypoxia affects key epigenetic players and molecular processes that control cellular differentiation.