GPR17 and myeloid sarcoma: Instead, our analysis refers to GPR17 protein and GPR17-expressing cells in specific areas; (b) it was a bulk analysis in which MS plaques were not characterized according to the histological classification [19], while the present data show that pre-active, active, inactive, chronic and acute lesions are characterized by highly different expression levels of GPR17; (c) the Chen et al. analysis did not consider the anatomy of the lesions, whereas in the present study we have excluded the peri-plaque areas of NAWM, which we observed to be characterized by highly remarkable GPR17 positivity.