TGFB1 and breast cancer: Bone destruction results in the release of several cytokines, such as interleukin-6 (IL-6), tumor necrosis alpha (TNFα), and transforming growth factor-beta 1 (TGF-β1), which promote tumor cell growth and invasion [20]. EVs released from breast cancer cells induce activation of osteoclast cells and destroy the bone remodeling [21].