HIF1A and myeloid sarcoma: In MS lesions, HIF-1α is mainly upregulated in astrocytes and oligodendrocytes in the NAWM (Graumann et al., 2003; Zeis et al., 2008), neurons, astrocytes, and oligodendrocytes in pre-demyelinating MS lesions (Aboul-Enein et al., 2003; Marik et al., 2007), and in oligodendrocytes in active lesions with dying-back oligodendrogliopathy (Lassmann, 2003).