Biomarkers related to the cholesterol pathway, including HDL-C and LDL-C levels, apolipoproteins (ApoA1, ApoAII, ApoB, and ApoE), and other cholesterol metabolites, have been linked to the disruption of the blood–brain barrier [42] and neurodegeneration in MS [9]. The gene discussed is APOE; the disease is myeloid sarcoma.