Once macrophages are recruited in the tumors, hypoxia-dependent transcription factors HIF1/2α reprograms macrophages into pro-tumoral phenotype that expresses IL-6, VEGF, and inducible nitric oxide synthase (iNOS) and arginase to promote tumor growth, angiogenesis, and immunosuppression (124, 125). Here, HIF1A is linked to neoplasm.