Co-purification of bone resorbing activity and adenylate cyclase stimulating activity from human tumours associated with the humoral hypercalcaemia of malignancy

Establishment of a human undifferentiated thyroid cancer cell line producing several growth factors and cytokines

A cell line was established from undifferentiated giant cell carcinoma of the thyroid. The authors obtained cells from a 44-year-old patient admitted because of a rapidly growing anterior neck mass. The patient had significant leukocytosis and hypercalcemia shortly before her death. An autopsy revealed epidermoid metaplasia of the tumor cells. The cells (HTC/C3) had lost most of their differentiated functions. However, their thyroid nature was shown by peroxidase staining and by enzyme-linked immunostaining with Hashimoto patients' sera. The tumor extract was found to contain parathyroid (PTH)-like activity. Significant amounts of colony stimulating factor (CSF), which was further defined to be GM-CSF, and interleukin-1 alpha (IL-1 alpha) were detected in the conditioned media. Epidermal growth factor (EGF) binding to the HTC/C3 showed rich EGF receptors. Furthermore, the conditioned medium inhibited the binding of 125I-mEGF to HeLa cells, and transforming growth factor (TGF) was found repeatedly in the media.

Ameloblastoma with metastasis to the lung and associated hypercalcemia

A case of ameloblastoma with metastasis to the lung is reported. A rare feature of this case was that the metastasized ameloblastoma was associated with hypercalcemia without osteolytic bone metastasis.

Osteoclast-mediated osteolysis in bone metastasis from renal cell carcinoma

Osteolytic characteristics of bone metastasis from renal cell carcinoma were morphologically and biochemically investigated. First, undecalcified ground sections of bone metastases were made from four patients with renal cell carcinoma. Second, renal cell carcinoma cell line (RCC-K1) was established from one of the four patients, and its effect on bone resorption in vitro was examined. Marked proliferation and activation of osteoclasts around the tumor cells was histologically demonstrated. Conditioned medium from the RCC-K1 cells contained potent bone-resorbing activity in vitro. The activity was reduced to basal level by calcitonin, but was not blocked by indomethacin. The activity was lost after dialysis (MW cutoff 3500), while it was retained after 2 weeks of storage. Levels of prostaglandin E2 and 1,25-dihydroxyvitamin D of the RCC-K1-conditioned medium were insufficient to cause bone resorption in vitro. The conditioned medium did not stimulate cAMP accumulation in rat osteoblastic cells. These results suggest that renal cell carcinoma causes bone destruction through the stimulation of osteoclasts by locally secreting an unknown humoral factor or factors.