Evaluation of MS lesions again revealed exclusive induction of HSPB6 in astrocytes, as confirmed by co-localization of HSPB6 with GFAP (Fig. 3j–l) but not with Olig2 (Fig. 3m) or HLA-DR (Fig. 3n), and supported by the morphology of HSPB6+ cells. The gene discussed is OLIG2; the disease is myeloid sarcoma.