SDC1 and Miyoshi myopathy: Importantly, a progressive increase in microvascular density is observed during the transition from MGUS to SMM and from SMM to clinically active MM [55, 56], paralleled by the increase in the peripheral blood or in the BM of the serum levels of the major proangiogenic cytokines (VEGF, bFGF, HGF, and Syndecan-1) [57].