Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P43146 (tumour suppressor)
 5,935 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Identification of mutations, which cause genetic diseases can be difficult when the disease is caused by the mutation of a large gene, which contains multiple exons. Detection of these mutations by DNA sequencing can be made more efficient by using mutation detection methods for pre-screening to identify the affected exon and to screen for the presence of already identified mutations in family members. These screening methods include denaturing gradient gel electrophoresis (DGGE), temperature gradient gel electrophoresis (TGGE), single-strand conformation polymorphism, conformation-sensitive gel electrophoresis (CSGE), heteroduplex analysis and denaturing high-performance liquid chromatography (DHPLC). We discuss the advantages and shortcomings of these methods by reviewing the results of studies screening for mutations causing multiple endocrine neoplasia type 1 (MEN 1) syndrome, an autosomal dominant disorder characterized by endocrine tumours of the anterior pituitary gland, parathyroid glands, and pancreas. MEN 1 is caused by mutations of the MEN1 gene, a tumour suppressor gene, which contains one untranslated exon and nine exons. Previous studies have identified more than 400 germline and somatic mutations spreading across all the encoding sequence, and found no mutational "hot spot" or genotype-phenotype correlation. The wide diversity of mutations in the entire coding region of the MEN1 gene makes mutation screening time-consuming and expensive. We conclude that combination of mutation detection methods with DNA sequencing enhances the efficiency of identifying pathogenic mutations. However, it should be considered that experimental determination of the optimal electrophoresis conditions, such as using perpendicular electrophoresis to optimise DGGE or TGGE, is more useful than computerized algorithms to calculate these parameters.
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PMID:Genetic screening methods for the detection of mutations responsible for multiple endocrine neoplasia type 1. 1546 22

Multiple endocrine neoplasia (MEN) types 1 and 2 syndromes are rare hereditary cancer syndromes expressing a variety of endocrine and non-endocrine neoplasias and lesions. The improving of both molecular and clinical genetics knowledge helps health care providers in the whole spectrum of the clinical managements of MEN patients. The MEN1 gene, a tumour suppressor gene, is responsible of MEN1 syndrome, and is probably involved in the regulation of several cell functions, including DNA replication and repair and transcriptional machinery. RET proto-oncogene encodes for a receptor tyrosine kinase protein whose expression is fundamental for appropriate migration, development and differentiation of neuroendocrine cells originating from neural crest. Currently, DNA testing makes possible the early identification of germline mutation in asymptomatic mutant gene carriers in both MEN syndromes. Consequently, the combination of new genetic and diagnostic tools could permit a precocious detection of MEN-associated neoplasms, and in particular the identification of a strong genotype-phenotype correlations in MEN2 syndrome demonstrates an improving outcome and quality of life for affected subjects.
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PMID:Lessons from genes mutated in multiple endocrine neoplasia (MEN) syndromes. 1598 80

The pathogenesis, diagnosis and therapy of tumours originating from the endocrine pancreas represent one of the most exciting challenges of contemporary medicine. Some of these tumours appear as part of four hereditary syndromes (multiple endocrine neoplasia type 1 (MEN1), von Hippel-Lindau disease (VHL), neurofibromatosis type 1 and tuberous sclerosis) that are all inherited as autosomal dominant traits and result from mutations of tumour suppressor genes. Considering its clinical relevance, MEN1 appears to be the most important among these four syndromes. Tumours of the endocrine pancreas develop in 30-80% of patients carrying mutations of the MEN1 gene. Gastrinomas are the most frequent functioning tumours in MEN1 patients, followed by insulinomas, whereas other tumors e.g. glucagonoma, VIP-oma, GRF-oma and somatostatinoma occur very rarely. Tumours of the endocrine pancreas are infrequent in patients suffering from VHL, neurofibromatosis and tuberous sclerosis. In this review article, the authors present a synopsis of tumours of the endocrine pancreas related to these hereditary syndromes underlining the clinical characteristics, diagnostical and therapeutical possibilities.
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PMID:[Hereditary tumours of the endocrine pancreas]. 1650 19

Individuals with inherited cancer syndromes are at significant risk of developing both benign and malignant tumours as a result of a germline mutation in a specific tumour suppressor gene. Tumours of familial origin are a rare event in the head and neck but despite this, they deserve a growing interest. Familial paragangliomas are most of the time limited to the paraganglionar system, but also may be part of different syndromic associations. Since early detection of paragangliomas reduces the incidence of morbidity and mortality, genotypic analysis in the search of SDHB, SDHC and SDHD mutations in families of affected patients plays a front-line diagnostic role, leading to more efficient patient management. Multiple endocrine neoplasias type 1 are characterized by the simultaneous occurrence of at least two of the three main related endocrine tumours: parathyroid, enteropancreatic and anterior pituitary. These tumours arise from inactivating germline mutations in the MEN-1 gene. No clear correlation of MEN-1 genotype with genotype has emerged to date, and MEN-1 mutation testing in tumours is not used clinically because it have not implications for tumour staging. Multiple endocrine neoplasia type 2 is due to a germline mutation in the RET proto-oncogene. Hallmarks of MEN-2A (the commonest phenotypic variant) include medullary thyroid carcinoma, pheochromocytoma, and hyperparathyroidism. The most central clinical difference with MEN-1 is that the associated cancer can be prevented or cured by early thyroidectomy in mutation carriers. Individuals with neurofibomatosis type 1 present early in life with pigmentary abnormalities, skinfold freckling and iris hamartomas, as result of NF1 gene mutation. Neurofibromatosis 2 is caused by inactivating mutations of the NF2 gene, and is characterized by the development of nervous system tumours (mainly bilateral vestibular schwannomas), ocular abnormalities, and skin tumours. The molecular genetic basis of nasopharyngeal carcinomas remains unknown, but there is evidence for the linkage of these tumours to chromosome 3p. Finally, the high rate of p16 mutations in squamous cell carcinomas and the association of p16 with familial melanoma propose p16 as an ideal candidate gene predisposing to familial squamous cell carcinomas. The elucidation of the cellular processes affected by dysfunction in familial tumours of the head and neck may serve to identify potential targets for future therapeutic interventions.
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PMID:Tumours of familial origin in the head and neck. 1685 15

Multiple Endocrine Neoplasia type 1 (MEN1) is a rare autosomal dominant hereditary cancer syndrome presented mostly by tumours of the parathyroids, endocrine pancreas and anterior pituitary, and characterised by a very high penetrance and an equal sex distribution. It occurs in approximately one in 30,000 individuals. Two different forms, sporadic and familial, have been described. The sporadic form presents with two of the three principal MEN1-related endocrine tumours (parathyroid adenomas, entero-pancreatic tumours and pituitary tumours) within a single patient, while the familial form consists of a MEN1 case with at least one first degree relative showing one of the endocrine characterising tumours. Other endocrine and non-endocrine lesions, such as adrenal cortical tumours, carcinoids of the bronchi, gastrointestinal tract and thymus, lipomas, angiofibromas, collagenomas have been described. The responsible gene, MEN1, maps on chromosome 11q13 and encodes a 610 aminoacid nuclear protein, menin, with no sequence homology to other known human proteins. MEN1 syndrome is caused by inactivating mutations of the MEN1 tumour suppressor gene. This gene is probably involved in the regulation of several cell functions such as DNA replication and repair and transcriptional machinery. The combination of clinical and genetic investigations, together with the improving of molecular genetics knowledge of the syndrome, helps in the clinical management of patients. Treatment consists of surgery and/or drug therapy, often in association with radiotherapy or chemotherapy. Currently, DNA testing allows the early identification of germline mutations in asymptomatic gene carriers, to whom routine surveillance (regular biochemical and/or radiological screenings to detect the development of MEN1-associated tumours and lesions) is recommended.
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PMID:Multiple endocrine neoplasia type 1. 1701 5

Multiple endocrine neoplasia (MEN) are major predisposition syndromes to endocrine tumours and are characterised by an autosomal dominant disorder and full penetrance. MEN-1 is a major form of hyperparathyroidism associated with a high prevalence of endocrine tumours of the pancreas, pituitary gland, adrenal cortex and the lymphoid and bronchial endocrine tissues. MEN-2 is the familial syndrome of medullary thyroid carcinoma, associated with pheochromocytoma and hyperparathyroidism. Apart from the clinical expression of their allelic variants, both syndromes are different in their physiopathogenesis, in that MEN-2 is related to the constitutional activation of the proto-oncogene RET that encodes a putative tyrosine kinase receptor, while MEN-1 is a tumour suppressor gene model, related to mutations in the menin adapter-protein of multiple intracellular functions. The study of other rarer forms of predisposition to endocrine tumours, and especially to hyperparathyroidism, has uncovered new genes such as HRPT2, which show that multiple physiological routes, including the close regulation of transcription and genetic stability, may lead to the same clinical outcome. These hereditary models of endocrine cancer contribute as much to further physiopathogenic knowledge as to the therapeutic recommendations for managing these syndromes.
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PMID:[Pathogenic patterns of genetic predisposition to endocrine tumors]. 1737 13

The co-occurrence of parathyroid hyperplasia with pancreatic endocrine tumours and/or pituitary adenoma is classified as Multiple Endocrine Neoplasia type 1 (MEN-1) and is caused by a germ-line mutation in MEN-1 gene encoding a tumour suppressor protein, menin. This review presents clinical expressions, diagnosis and management of the MEN-1 syndrome. Properties and mechanisms of menin functions are also reviewed.
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PMID:Multiple Endocrine Neoplasia type 1. 1824 4

Multiple endocrine neoplasia type 1 (MEN1) is caused by inactivating germ line mutations of the MEN1 tumour suppressor gene. The MEN1 gene product, menin, participates in many cellular processes, including regulation of gene transcription. As part of a protein complex that writes a trimethyl mark on lysine 4 of histone H3 (H3K4me3), menin is involved in activating gene transcription. Several functions of the menin histone methyltransferase complex have been discovered through protein interaction studies. Menin can interact with nuclear receptors and regulate transcription of hormone responsive target genes. Menin regulates transcription of cyclin-dependent kinase inhibitor and Hox genes via the chromatin-associated factor LEDGF. Aberrant expression of menin target genes in tumours in MEN1 patients suggests that loss of writing of the H3K4me3 mark contributes to MEN1 tumourigenesis. At present, drugs are being developed that target chromatin modifications. The identification of compounds that could restore H3K4me3 on menin target genes would provide new therapeutic strategies for MEN1 patients.
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PMID:Multiple endocrine neoplasia type 1: a chromatin writer's block. 1952 25

A genetic predisposition for paragangliomas and adrenal or extra-adrenal phaeochromocytomas was recognized years ago. Beside the well-known syndromes associated with an increased risk of adrenal phaeochromocytoma, Von Hippel Lindau disease, multiple endocrine neoplasia type 2 and neurofibromatosis type 1, the study of inherited predisposition to head and neck paragangliomas led to the discovery of the novel 'paraganglioma-phaeochromocytoma syndrome' caused by germline mutations in three genes encoding subunits of the succinate dehydrogenase (SDH) enzyme (SDHB, SDHC and SDHD) thus opening an unexpected connection between mitochondrial tumour suppressor genes and neural crest-derived cancers. Germline mutations in SDH genes are responsible for 6% and 9% of sporadic paragangliomas and phaeochromocytomas, respectively, 29% of paediatric cases, 38% of malignant tumours and more than 80% of familial aggregations of paraganglioma and phaeochromocytoma. The disease is characterized by autosomal dominant inheritance with a peculiar parent-of-origin effect for SDHD mutations. Life-time tumour risk seems higher than 70% with variable clinical manifestantions depending on the mutated gene. In this review we summarize the most recent knowledge about the role of SDH deficiency in tumorigenesis, the spectrum and prevalence of SDH mutations derived from several series of cases, the related clinical manifestantions including rare phenotypes, such as the association of paragangliomas with gastrointestinal stromal tumours and kidney cancers, and the biological hypotheses attempting to explain genotype to phenotype correlation.
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PMID:SDH mutations in tumorigenesis and inherited endocrine tumours: lesson from the phaeochromocytoma-paraganglioma syndromes. 1952 23

Carney complex (CNC) is an autosomal dominant, multiple endocrine neoplasia syndrome comprised of spotty skin pigmentation, myxomatosis, endocrine tumours and schwannomas. The majority of cases are due to inactivating mutations in PRKAR1A, the gene encoding the type 1A regulatory subunit of the 3',5'-cyclic adenosine monophosphate (cAMP)-dependent protein kinase, PKA (protein kinase A). In order to understand the molecular basis for tumorigenesis associated with PRKAR1A mutations, we have developed conventional and conditional Prkar1a knockout (KO) mice as well as primary cell culture models corresponding to these genetic manipulations. At the biochemical level, removal of Prkar1a from cells causes enhanced PKA activity, the same effect which has been observed in tumours isolated from CNC patients. Mice heterozygous for Prkar1a mutations (the exact genetic model for CNC patients) are born at expected frequencies and are tumour prone, developing neoplasms in cAMP-responsive cell types such as Schwann cells, osteoblasts and thyrocytes. In order to understand the basis of tissue-specific tumour formation, we have created tissue-specific KOs of the gene from three different tissues: the neural crest (Schwann cells), the pituitary gland and the heart. In the neural crest and the pituitary, ablation of Prkar1a leads to excess proliferation and tumorigenesis, whereas the same manipulation in developing cardiomyocytes leads to reduced proliferation and embryonic demise. The KO hearts also exhibit myxomatous changes suggesting a connection between PKA activation and myxomagenesis, although the nature of this relationship has not yet been determined. This work confirms the role of Prkar1a as a tissue-specific tumour suppressor, and ongoing work is focused on identifying the key downstream signalling targets affected by dysregulation of PKA.
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PMID:Use of mouse models to understand the molecular basis of tissue-specific tumorigenesis in the Carney complex. 1952 26


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