IL11 and breast cancer: For instance, IL-11 activates STAT3 in cancer-associated fibroblasts, and promotes colorectal tumor development, and correlates with poor prognosis.55 In breast cancer, tumor cell-derived IL-11 may promote osteolysis by increasing the pool of osteoclast progenitor cells.56 IL-11 is also essential in promoting osteolysis in breast cancer bone metastasis.57 Thus, it is likely that IL-11 release may serve as the first step after dysbiosis of the gut microbiome, followed by activation of the SOX9 in ABX or GF mice.