In actively remyelinating areas of MS tissue, oligodendrocyte lineage cells expressing Acvr2a consistently outnumber cells expressing Acvr2b suggesting that an increase in Acvr2b expression may impair oligodendrocyte differentiation and myelin formation induced by Acvr2a (Dillenburg et al., 2018). Here, ACVR2B is linked to myeloid sarcoma.