TGFB1 and breast cancer: Transforming growth factor beta (TGF‐β) has a proven central role in breast cancer metastasis to the skeleton where the cytokine induces EMT, with host‐derived TGF‐β acting on tumor cells using PTHrP as an effector.(65) We confirm here that PTHrP is likely a crucial intermediate in this process because its absence reverses EMT and significantly reduces the invasive motile state of TNBC cells.