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

Parathyroid adenomas are benign uniglandular tumors and are the most common cause of primary hyperparathyroidism. Several genetic changes in parathyroid tumors, including inactivation of tumor suppressor genes, activation of oncogenes and loss of heterozygosity at several chromosomal loci, have been reported. In this study, we analyzed the status of cyclin D1 and beta-catenin in 24 cases of parathyroid adenoma. Immunohistochemistry of cyclin D1 showed positive staining in 9 (37.5%) of the 24 parathyroid adenomas. The status of beta-catenin, which has recently been identified as a regulator of cyclin D1 transcription, was examined by direct sequencing of exon 3 of the beta-catenin gene and immunohistochemistry of beta-catenin protein, but neither mutation nor accumulation of beta-catenin was detected in any of the cases. These results indicate that cyclin D1 is frequently accumulated in parathyroid adenomas, independently of dysfunction in the Wnt signaling pathway.
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PMID:Immunohistochemistry of cyclin D1 and beta-catenin, and mutational analysis of exon 3 of beta-catenin gene in parathyroid adenomas. 1183 55

Misregulation of the Wnt/beta-catenin signalling pathway is involved in the development and progression of many cancers. Recently, we presented evidence for aberrant accumulation of non-phosphorylated (stabilized) beta-catenin in benign parathyroid tumors from patients with primary hyperparathyroidism (pHPT) or HPT secondary to uremia (sHPT). Here we have used a human parathyroid hormone (PTH)-producing cell line (sHPT-1), established from a hyperplastic parathyroid gland removed at operation of a patient with sHPT, to further investigate the potential importance of beta-catenin in parathyroid tumorigenesis. Our studies demonstrate that efficient and specific knockdown of beta-catenin by small interfering RNA (siRNA) markedly decreased endogenous beta-catenin transcriptional activity as well as expression of the Wnt/beta-catenin target genes cyclin D1 and c-myc, known to be overexpressed in a substantial fraction of parathyroid tumors. Furthermore, siRNA to beta-catenin inhibited cellular growth and induced cell death. Growth and survival of the parathyroid tumor cells are thus dependent on maintained expression level of beta-catenin. The Wnt/beta-catenin signalling pathway, and beta-catenin in particular, presents a potential therapeutic target for HPT.
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PMID:Activated beta-catenin in the novel human parathyroid tumor cell line sHPT-1. 1712 1

Primary hyperparathyroidism (PHPT) is one of the most frequent endocrinological disorders. In PHPT, there is abnormal regulation of parathyroid hormone (PTH) by calcium, which translates into inappropriately high PTH secretion for the level of calcemia. Most patients with PHPT have increased serum PTH levels, with increases in serum calcium, especially ionic calcium. The incidence of PHPT rises with age, the mean age at diagnosis being 55 years. This disorder affects mainly women with a female-to-male ratio of approximately 3:1. Most (80-85%) of cases are produced by chief cell parathyroid adenomas. The factors involved in the genesis of PHPT are largely unknown. Gene mutations affecting oncogenes (cyclin D1, RET) or tumor suppressor genes (MEN1, HRPT2) are found in a minority of cases. These mutations are especially important in familial forms of PHPT, such as multiple endocrine neoplasia syndrome (MEN1, MEN2A). No mutations affecting the calcium-sensing receptor (CaSR) or vitamin D receptor (VDR) gene have been found. In parathyroid adenomas and hyperplasias, there may be abnormal Wnt signalling, with mutations of the coreceptor LRP5 gene and beta-catenin accumulation. Expression of the Klotho protein, which intervenes in serum calcium regulation, is reduced. Low levels of 25(OH) vitamin D frequently coexist, although whether vitamin D deficiency plays a pathogenic role in PHPT is unknown.
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PMID:[Concept, etiology and epidemiology of primary hyperparathyroidism]. 1962 54