NANOG and breast carcinoma: The expression of ALKBH5 was induced by hypoxia in breast cancer cells depending on hypoxia-inducible factor (HIF)-1α and HIF-2α, and the upregulation of ALKBH5 mediated the enrichment of breast cancer cell in hypoxic tumor microenvironment, through enhancing NANOG expression, therefore advancing tumor formation in vivo [24].