Because BM levels of adenosine are higher in MM patients compared to those in patients with monoclonal gammopathy of undetermined significance (MGUS) or smoldering myeloma (SMM), EVs containing CD38, or similar ectoenzymes (CD39 and CD73) highly released in circulation [77], might be used as potential screening markers for differentiation of these conditions, as well as the different stages of MM. Here, CD38 is linked to Miyoshi myopathy.