Ectopic production of parathyroid hormone by small cell lung cancer in a patient with hypercalcemia.
Severe hypercalcemia (serum calcium, 4.37-4.84 nmol/L) was found in a 70-yr-old man who had a small cell carcinoma of the lung with multiple metastases. The plasma immunoreactive PTH concentration was markedly elevated, as measured in three different PTH assays [N-terminal PTH, 4,650 ng/L (normal, 230-630); midregion PTH, 13,850 ng/L (normal, 180-560); C-terminal PTH, 9,900 ng/L (normal, less than 1,300)], but at autopsy the parathyroid glands were histologically normal. The PTH concentration of a liver metastasis was 503.5 ng/g wet wt (normal liver, less than 4.2-5.9), and the PTH in the tumor extract eluted at nearly the same position as synthetic human PTH-(1-84) on gel filtration chromatography. Northern blot analysis revealed PTH mRNA in the tumor as a single band of 0.9 kilobase. These results indicate that the ectopic PTH production by the lung cancer was the cause of hypercalcemia in this patient.
Yoshimoto
K
K
First Department of Internal Medicine, School of Medicine, University of Tokushima, Japan.
Yamasaki
R
R
Sakai
H
H
Tezuka
U
U
Takahashi
M
M
Iizuka
M
M
Sekiya
T
T
Saito
S
S
D000368:Aged; D018288:Carcinoma, Small Cell / Q000032:analysis / Q000097:blood / Q000378:metabolism*; D004586:Electrophoresis / Q000379:methods; D006801:Humans; D006934:Hypercalcemia / Q000097:blood*; D008113:Liver Neoplasms / Q000032:analysis / Q000556:secondary; D008175:Lung Neoplasms / Q000032:analysis / Q000097:blood / Q000378:metabolism*; D008297:Male; D009693:Nucleic Acid Hybridization; D009384:Paraneoplastic Endocrine Syndromes; D010281:Parathyroid Hormone / Q000097:blood* / Q000235:genetics; D012333:RNA, Messenger / Q000032:analysis; D014020:Tissue Extracts / Q000032:analysis
D010281:Parathyroid Hormone; D012333:RNA, Messenger; D014020:Tissue Extracts