Irrespective of the specific mechanism, when injected into a preclinical mouse model, the “educated” MSCs promoted osteosarcoma growth and formation of lung metastasis, supporting the establishment of a tissue microenvironment favoring tumor growth and metastasis formation through the induction of the pro-inflammatory IL-6/STAT3 pathway (Baglio et al., 2017). Here, IL6 is linked to osteosarcoma.