CTSG and breast neoplasm: To study the effect of TAK1 inhibition on established primary breast tumors, MDA-MB-231 cells tagged with green fluorescent protein (GFP) and luciferase (MDA-MB-231-GFP/luc) were injected into the mammary fat pads of NSG (NOD.Cg-Prkdcscid Il2rgtm1Wj1/SzJ) mice.