CXCR4 and Miyoshi myopathy: Other drugs, including cell signaling targeted therapies (PI3K/AKT/mTOR, p38 MAPK, Hsp90, Wnt, Notch, Hedgehog, and cell cycle) and strategies targeting the tumor microenvironment (hypoxia, angiogenesis, integrins, CD44, CXCR4, and selectins) are candidates for the treatment of refractory and relapse MM [220].