CXCR4 levels are higher in circulating MM cells than in those resident in the bone marrow.54 Further, hypoxia induces upregulation of CXCR4 in a HIF1α-dependent manner in MM.58 The hypoxic bone microenvironment conditions also promote Pim activity with inhibition of the ubiquitin-mediated proteasomal degradation of Pim.59 The gene discussed is CXCR4; the disease is Miyoshi myopathy.