CCL2 and neoplasm: Tumor-associated MSCs differ from BM-MSCs in several ways; for instance, an in-depth in vivo analysis revealed that, unlike their BM-MSC counterparts, these L-MSCs produced high levels of the C–C motif chemokine receptor 2 (CCR2) ligands CCL2, CCL7, and CCL12, which promoted the recruitment of macrophages to tumor sites where they underwent a phenotypic shift to the tumor-promoting M2-like phenotype [27].