TNF and neoplasm: The ability of TNFα to potentiate the in vivo aggressiveness of TNBC cells grown with MSCs requires that the in vitro advantages given to the tumor cells by their 3-day exposure to MSCs and to the cytokine, will persist in vivo (the cytokine is removed prior to injection to mice); Thus, we first determined whether the increased pro-metastatic capabilities endowed on the tumor cells by their co-culturing with stromal cells in the presence of TNFα withhold when TNFα is removed.