These in vivo results although were unpredicted based on our in vitro results and the fact that we had expected higher therapeutic effects of the armed MYXV construct with a pro-inflammatory cytokine like TNF, as had been observed in a syngeneic lung metastatic osteosarcoma model [13]; however our in vivo results were not entirely surprising since TNF has been reported by others to promote IL-6, a propagating factor for MM [30, 31] that suppresses apoptosis of MM by activating the NF-κB-pathway [32]. Here, TNF is linked to osteosarcoma.