PTHLH and cancer: Hypercalcemia is a relatively common paraneoplastic syndrome, and recent studies have demonstrated that parathyroid hormone-related protein (PTHrP) secreted by tumor cells can cause hypercalcemia in patients with malignant tumors [4, 5], while leukocytosis is a paraneoplastic syndrome caused by tumor-derived granulocyte colony-stimulating factor (G-CSF) [6].