CCL2 and osteosarcoma: As a consequence, CCL2, CXCL1, IL-6 and IL-8 levels are further increased in the tumor microenvironment, eliciting mesenchymal to amoeboid transition of osteosarcoma cells through activation of Ras homology family member A (RHOA) signaling, which promotes motility, invasiveness and trans-endothelial tumor cell migration [153].