FN1 and myeloid sarcoma: Active targeting of Fn aggregates is relevant for both functional cellular delivery of therapeutic agents that bypass Fn-mediated inhibition of remyelination (e.g., GD1a), and treatment approaches aimed to clear Fn aggregates at MS lesions (e.g., MMP7), with the latter requiring extracellular release of nanoparticle content or local stimulation of MMP production.