The considerable amount of fibronectin produced by astrocytes and the ability of astrocytic fibronectin to become aggregated after treatment with lipopolysaccharide led to conclude to the deleterious effects of such aggregates on oligodendrocyte differentiation and myelin regeneration in vivo, in agreement with the detection of a low level of fibronectin aggregates in remyelinated MS lesions (Stoffels et al., 2013). This evidence concerns the gene FN1 and myeloid sarcoma.