IL6 and neoplasm: EM-DR is rapidly induced by signaling events that are initiated by factors present in the tumor microenvironment and can be subdivided into two categories: soluble factor-mediated drug resistance (SFM-DR), which is induced by cytokines, chemokines, and growth factors secreted by MSCs such as IL-6, IGF-1, IL-1, IL-17 and TNF-α; and cell adhesion-mediated drug resistance (CAM-DR), which is mediated by the adhesion of tumor cell integrins to MSCs or stromal fibroblasts or components of the ECM, such as fibronectin, laminin, hyaluronan and collagen IV [11,86,87,88].