A recent study showed that the levels of the proteolytic fragment peptide PTHrP (12–48) are high in the plasma (range: 50 pg/μl to >200 pg/μl, with a mean of ~100 pg/μl or ~10 nM) of human patients with breast cancer bone metastasis vs. non-bone metastatic breast cancers (Washam et al., 2013). Here, PTHLH is linked to breast carcinoma.