Given the inhibitory effects of tumor-derived CCL2 on myoblasts and myotubes in vitro, we determined how targeting of CCL2 expression in breast tumors would affect SMW in vivo by knocking down CCL2 through the delivery of TAT cell-penetrating peptides with calcium cross-links to siRNAs (Ca-TAT/siRNAs). The gene discussed is CCL2; the disease is breast neoplasm.