HIF1A and fibrosarcoma: Another example is Nicotinamide phosphide bosyltransferase (NAMPT), which has been found to be a metabolic gate for mobilization of MDSC and could be motivated by CSF-1, inhibiting the transcription of CXCR4 through the NAD/Sirtuin1 axis driven by hypoxia-inducible factor 1 alpha (HIF1α), leading to MDSCs activation and M2 polarization in syngeneic orthotopic fibrosarcoma and mammary carcinoma mouse models [91].