Phagocytosis and processing of debris are believed to be fundamental features of beneficial microglia function in several CNS pathologies and our transcriptome analysis associated ERK1/2 activated microglia to signatures found in human MS lesions described as “foamy” microglia (e.g., Spp1, Msr1, Cd84)56. Here, MSR1 is linked to myeloid sarcoma.