BCAS1 and myeloid sarcoma: Recent studies have started to uncover genes enriched in iOLs, such as Itpr2 (Zeisel et al., 2015; Marques et al., 2016), Enpp6 (Xiao et al., 2016), and Bcas1 (Fard et al., 2017), that could be used as markers for these transient cell populations, particularly interesting to label areas of active (re)myelination in the context of OL and myelin pathology, such as preterm brain injury and MS.