Another work assessed the plasma concentrations of total and free PROS1 in 65 patients with multiple sclerosis (MS) and 15 controls; total PROS1 in MS was reduced compared with control, while plasma-free PROS1 was extremely lower in patients with higher disease severity, suggesting that the PROS1 level may be a potential biomarker of disease progression (47). The gene discussed is PROS1; the disease is myeloid sarcoma.