<prompt> A 65 years old male diagnosed by biopsy a case of lung carcinoma, with paraneoplastic syndrome and increased PTH. Probable cause is-ParathyroidParathyroid related peptideCalcitoninCalcitonin related peptide  <response>: Hypercalcemia is seen in squamous cell carcinoma of lung. The causal mechanism is the production of calcemic humoral substances, most impoantly parathyroid hormone-related protein PTHRP . It has sone biological action similar to PTH. Several other factors like IL-1, TGF, TNF and dihydroxy vitamin D have also been implicated Pathologic basis of Disease, 8 th edition 