PTHLH and neoplasm: Molecular crosstalk between tumour cells and the bone marrow micro-environment is mediated by direct cell-to-cell interactions and paracrine signalling molecules, such as transforming growth factor β (TGFβ), fibroblast growth factors (FGFs), platelet-derived growth factor (PDGF), insulin-like growth factor (IGF), Jagged, parathyroid hormone-related protein (PTHrP), and receptor activator of nuclear factor kappa-Β ligand (RANKL) [10].