IL6 and breast cancer: Although most of the preclinical studies identified specific key ILs which promote breast cancer metastases to bone, which have a pro-metastatic effects (IL-6, IL-8, IL-1β, IL-11), and whose inhibition also shows potential preclinical therapeutic effects, the ongoing clinical trials seemed to focus principally on ILs that have anti-metastatic effects and a potential to generate a localized and systemic antitumor response.