Parathyroid hormone related protein and hypercalcaemia in breast cancer.
OBJECTIVE
To see whether parathyroid hormone related protein has a humoral role in breast cancer.


METHODS
Plasma concentrations and tumour expression of parathyroid hormone related protein were determined (by two site immunoradiometric assay and immunohistochemistry respectively) in women with breast cancer and related to the presence of bone metastases and serum calcium concentrations.


METHODS
Plasma concentrations of parathyroid hormone related protein were measured in 57 women with early breast cancer without apparent bone metastases, 28 women with bone metastases, and 13 women with bone metastases and hypercalcaemia. Tissue positivity for parathyroid hormone related protein was determined retrospectively in 106 primary breast tumours from women without apparent bone metastases and 72 tumours from women with bone metastases, 25 of whom subsequently developed hypercalcaemia.


RESULTS
Plasma parathyroid hormone related protein concentrations were detectable (greater than 0.23 pmol/l) in 12 (92%) of the 13 hypercalcaemic patients with bone metastases compared with 10 (36%) of the 28 normocalcaemic patients with bone metastases and five (9%) of the 57 normocalcaemic patients without bone metastases. Parathyroid hormone related protein concentrations were significantly higher in hypercalcaemic than normocalcaemic patients with bone metastases. Tumour staining was positive for parathyroid hormone related protein in 22 (88%) of the 25 primary breast cancers from patients with bone metastases. Tumour staining was positive for parathyroid hormone related protein in 22 (88%) of the 25 primary breast cancers from patients with bone metastases who later developed hypercalcaemia compared with 25 (53%) of the 47 from women in this group who remained normocalcaemic and 55 (52%) of the 106 early breast cancers from women without known metastases.


CONCLUSIONS
Tumour derived parathyroid hormone related protein may have an important humoral role in hypercalcaemia associated with metastatic breast cancer.
Bundred
N J
NJ
Department of Surgery, Selly Oak Hospital, Birmingham.
Ratcliffe
W A
WA
Walker
R A
RA
Coley
S
S
Morrison
J M
JM
Ratcliffe
J G
JG
D001859:Bone Neoplasms / Q000737:chemistry / Q000378:metabolism / Q000556:secondary*; D001940:Breast / Q000378:metabolism; D001943:Breast Neoplasms / Q000097:blood / Q000737:chemistry* / Q000378:metabolism; D002118:Calcium / Q000097:blood; D005260:Female; D006801:Humans; D006934:Hypercalcemia / Q000097:blood* / Q000209:etiology / Q000378:metabolism; D007150:Immunohistochemistry; D009363:Neoplasm Proteins / Q000097:blood* / Q000378:metabolism; D044162:Parathyroid Hormone-Related Protein; D011506:Proteins / Q000032:analysis* / Q000378:metabolism
D009363:Neoplasm Proteins; C470121:PTHLH protein, human; D044162:Parathyroid Hormone-Related Protein; D011506:Proteins; D002118:Calcium