IL6 and neoplasm: Under favorable conditions, tumor cells are able to induce a switch in these stromal cells, turning them into tumor-associated stromal cells, which can secrete many pro-tumorigenic factors, including interleukin 6 (IL-6), IL-8, stromal-derived factor-1 alfa (α-SDF1), vascular endothelial growth factor (VEGF), tenascin-C and matrix metalloproteinases, among other factors, all of which recruit additional tumor and pro-tumorigenic cells to the developing microenvironment [25].