CXCR4 and Miyoshi myopathy: Interestingly, new data in vitro has shown that SDF-1α stimulation of CXCR4 on MM cells may up-regulate the expression of IL-6 through the activation of the PI3K/AKT, suggesting that the IL6 and CXCR4/CXCL12 pathways overlap in MM cells (64).