For example, SDF-1/C-X-C Motif Chemokine Receptor 4 (CXCR4), a chemokine/chemokine receptor axis involved in stem cell trafficking and cancer metastasis, plays a major role in MSC tumor infiltration (Phillips et al., 2003; Kucia et al., 2004). Here, CXCR4 is linked to neoplasm.