SDC1 and Miyoshi myopathy: In fact, selection of CD38+/CD138+ cells from MM patients enriches for a highly malignant population [117, 118], while cell surface-shedding of the proteoglycan and accumulation of Syndecan-1/CD138 fragments in the bone-marrow tumour milieu and in circulation sets up a detrimental chemoresistance loop [119, 120].