IL6 and cancer: Thus, at least four remote signals were secreted by metastasizing 4T1 cancer cells; these induced (1) recruitment of MDSCs to various sites of tumor-bearing hosts, (2) increased expression of IL-6Rα, (3) increased expression of Adam family proteases, and (4) highly increased expression of IL-6 by MDSCs [34,35,18,19,29].