TGFB1 and bone metastasis: Plasma TGF-β1 levels have also been determined in 49 bone metastasis patients, including 23 breast cancer patients, and were reported to be elevated in more than half of the cancer patients and positively correlated with TGF-β signaling related markers, including parathyroid thyroid hormone-related peptide (PTHrP) and interleukin 10(IL-10) [66].