STAT3 and cancer: The role of NF-kB in cancer is manifold and complex [32, 33]; NF-kB induces the secretion of pro-tumorigenic cytokines, such as IL-6, and this, in turn, is likely to have a paracrine effect on OS cells via activation of the STAT3 pathway [34, 35], a well known activator of cell proliferation [36], suggesting that stromal cells co-evolve with tumor cells to enhance tumor aggressiveness.