Given that CXCL12 functions to trigger chemotactic migration in a wide range of CXCR4-expressing cells [59–61], it would be worthwhile to investigate if the CXCR4-CXCL12 axis is also important for the mobilization of MDSCs and subsequent tumor progression through the induction of an immunosuppressive microenvironment. This evidence concerns the gene CXCR4 and neoplasm.