CCL17 and neoplasm: In bone metastases from breast cancer, ERRα also improved anti-tumor immune responses [87] via the release of chemokines (CCL17, CCL20) and reduced synthesis of TGFβ3, allowing infiltration of cytotoxic CD8+ T cells and mitigating metastatic burden both in mice and humans, thus leaving the question open if agonism or antagonism of ERR is favorable for tumor patients.