There are four causes of malignancy-associated hypercalcemia: (1) increased production of PTH-related peptide (PTHrP) by tumor cells (termed as humoral hypercalcemia of malignancy); (2) bone dissolution by metastasis from a tumor or multiple myeloma due to release of local PTHrP and osteolysis; and (3) excess PTH production by cancerous cells (ectopic PTH production or from parathyroid carcinoma) which is rare [1, 7]. The gene discussed is PTHLH; the disease is plasma cell myeloma.