PTHLH and breast cancer: We must mention here that the PTHrP concentration used in these experiments (1 μM = 10 pmol in 10 μl injection volume) are based on a recent finding that 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).