CXCR4 and neoplasm: ,52 Based on previous studies demonstrating that GRP78 is associated with tumor metastasis and invasion through increased cell motility, we investigated whether GRP78 could enhance the tumor-homing abilities of MSCs.53, 54, 55 SDF-1 preconditioning did not increase C-X-C motif receptor 4 (CXCR4) expression in MSCs, and pretreatment of MSCs with IGF-1 resulted in no significant change in the expression levels of homing-related proteins (data not shown).