As a major component of the calcium homoeostatic system [7], the CaSR contributes to the development of CIH by promoting the growth and metastatic properties of tumor cells [8, 9] and/or by promoting the secretion of tumor cell-derived osteolytic factors such as parathyroid hormone-related protein (PTHrP) [10–12]. The gene discussed is PTHLH; the disease is neoplasm.