Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0221002 (primary hyperparathyroidism)
 4,921 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Primary hyperparathyroidism is the clinical result of parathyroid adenoma or hyperplasia, rarely of carcinoma. Clinical, serologic, and radiologic data are unable to discriminate a single parathyroid adenoma from an enlarged hyperplastic gland. Morphologic features also overlap in adenoma and small hyperplastic gland. Studying immunohistochemical expression of fatty acid synthase (FAS), p53, Ki67 and bcl-2, we found that among 21 adenomas 19 (90.5%) were positive for FAS, 12 (57.2%) for Ki67, 11 (52.4%) for p53, and 16 (76.2%) for bcl-2; among 12 hyperplasias, 12 (100%) were positive for FAS, 6 (50%) for KI67, 8 (66.7%) for p53, and 8 (66.7%) for bcl-2. Statistical analysis showed that FAS was associated with parathormone (PTH) (P =.001), Ki67 (P =.01), and p53 (P =.01). Moreover, FAS was associated with hyperplastic (P =.0001) and adenomatous glands (P =.0001). Ki67 was associated with both adenomatous (P =.02) and hyperplastic glands (P =.005). P53 protein were associated only with hyperplastic glands (P =.01). The different occurrence of p53 in parathyroids adenoma and hyperplasia may enable a different management and follow-up of the patients with primary hyperparathyroidism, stratifing them into two groups. The first, with a "false" adenoma having a high risk of relapse, may necessitate exams like serum calcium levels, PTH concentrations, urinary calcium levels for 24 hours, kidney functional tests, and radiology and ultrasound every 3 to 6 months, whereas the second with "true" adenoma, at low risk of relapse, may be checked less frequently with serum calcium levels and PTH concentrations.
 ...
PMID:P53 as a marker of differentiation between hyperplastic and adenomatous parathyroids. 1217 Apr 54

The cloning of the calcium sensing receptor (CaR) confirmed that parathyroid cells monitor extracellular calcium concentration ([Ca2+]ext) via a receptor-type mechanism. This lead to the hypothesis that abnormalities in the expression and/or function of the CaR could explain the biochemical abnormalities in primary hyperparathyroidism (PHPT). Cultured cells from parathyroid adenomas of patients operated for PHPT were used to monitor real-time changes in intracellular calcium concentration ([Ca2+]i) as measured by fluorescent microscopy using the Fura-2/AM dye. We found that CaR agonists trigger release of intracellular calcium pools and such responses are amplified by increasing the affinity of IP3 receptors. Using confocal microscopy to monitor membrane trafficking in living parathyroid cells labelled with the fluorescent dye FM1-43, we found that a decrease in [Ca2+]i rather than an absolute change in [Ca2+]ext is the main stimulus for exocytosis from human parathyroid cells. These data suggest that, in PHPT, a defective signalling mechanism from the CaR allows cells from parathyroid adenomas to maintain low [Ca2+]i with uninhibited PTH secretion in the face of hypercalcaemia. Over longer periods of time, CaR controls parathyroid proliferation via changes in tyrosine phosphorylation. We found that multiple proteins of molecular weight 20-65 kDa are phosphorylated within 10-60 min in response to CaR agonists. Further work demonstrated that high [Ca2+]i stimulates the expression of bcl-2 oncoprotein in cultured human parathyroid cells and that, in parathyroid adenomas, predominant expression of bcl-2 rather than bax oncoprotein might prevent apoptosis and explain the slow growth rate of these tumours. More recently, it became apparent that CaR stimulates cell proliferation in several cell types not involved in calcium homeostasis. Using archived histological material from 65 patients who died with metastatic breast cancer, we identified CaR expression predominantly in tumours from patients who developed bone rather than visceral metastases (35 of 49 versus 7 of 16; P < 0.01, chi-squared test). These data suggest that CaR expression has the potential to become a new biological marker predicting the risk of bone metastases in patients with breast cancer. A prospective study should investigate if patients with CaR-positive tumours are more likely to develop bone metastases and whether they could benefit more from prophylactic treatment with bisphosphonates or the newly developed CaR antagonists.
 ...
PMID:The calcium sensing receptor: from understanding parathyroid calcium homeostasis to bone metastases. 1849 87