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. Here, SOX9 is linked to breast cancer.