The evidence for this comes from the experiments that showed that (A) TRAF2 is highly expressed in the osteotropic MDA-231-BT cells when compared to parental control, (B) knockdown of TRAF2 in osteotropic MDA-231-BT inhibited cell migration and reduced the ability of these cells to enhance osteoclastogenesis, (C) conditioned medium from osteotropic MDA-231-BT overexpressing TRAF2 reduced osteoblast ability to form bone nodules in vitro, and (D) upregulation of TRAF2 worsened breast cancer-induced osteolysis. The gene discussed is TRAF2; the disease is breast cancer.