Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.7.10.1 (ERK)
 95,504 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Genetic alteration of the RET proto-oncogene is associated with multiple endocrine neoplasia type 2A and 2B (MEN 2A and MEN 2B), familial medullary thyroid carcinoma (FMTC) and Hirschprung's disease. Oncogenically activated RET has also been demonstrated in sporadic medullary thyroid tumors, which in some cases show somatic missense mutations. We have recently described a complex 9 bp deletion in RET exon 11 in a single case of sporadic MTC. In order to determine the prevalence of this mutation among sporadic MTC tumors, we have now analysed 15 cases and five normal controls by PCR-based nonradioactive single-strand conformational polymorphism analysis (PCR-SSCP) and fragment size analysis of exon 11. DNA was extracted from microdissected tumor tissue or normal cells and subjected to nested PCR prior to analysis. A markedly divergent SSCP pattern and a PCR fragment 9 bp shorter than normal were demonstrated in 14 of the 15 MTC tumors. Sequencing revealed the deletion of nine bases encompassing a key cysteine at codon 634, often altered in MEN 2A. Four lymphocyte controls and normal thyroid tissue from one patient failed to show the deletion. Several factors in the DNA sequence environment immediately surrounding the deletions, including an extended inverted repeat, several direct repeats and a so-called symmetric element suggest that the deletional events may be non-random.
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PMID:A complex nine base pair deletion in RET exon 11 common in sporadic medullary thyroid carcinoma. 916 Aug 84

Multiple endocrine neoplasia type 2 (MEN-2) is a familial cancer syndrome inherited in an autosomal dominant fashion with age-related penetrance. The main tumour type present in all manifestations of this syndrome. MEN-2A, MEN-2B and familial medullary thyroid carcinoma (FMTC), is medullary thyroid carcinoma (MTC). MTC arises from the parafollicular or C cells of the thyroid. MEN-2A is characterised by the triad of MTC, phaeochromocytoma, and parathyroid hyperplasia. MEN-2B is characterised by features similar to those of MEN-2A, except for the absence of clinically apparent parathyroid hyperplasia, and additional stigmata including a marfanoid habitus, mucosal neuromas and ganglioneuromatosis of the gastrointestinal tract. FMTC families have MTC as their only phenotype. Missense mutations affecting conserved cysteine codons adjacent to the transmembrane domain of the RET proto-oncogene have been identified in the germline DNA of patients with MEN-2A and FMTC. A single mutation at codon 918 in the tyrosine kinase domain of the RET receptor has been associated with the MEN-2B phenotype. In a small number of FMTC families, missense point mutations have also been identified in the intracellular domain of the RET protein. RET mutation analysis of MEN-2 families has allowed the identification of genotype-phenotype correlations. While 25% of all MTCs are hereditary, the great majority of MTCs, 75%, are sporadic. Various somatic RET mutations have been identified in sporadic MTCs. In a small number of hereditary MTCs with germline mutations in RET, an additional somatic missense RET mutation has been identified. The discovery of RET mutations in MEN-2 has made possible accurate DNA-based diagnosis and predictive testing. The clinical significance of somatic RET mutations has yet to be determined.
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PMID:RET proto-oncogene mutations in multiple endocrine neoplasia type 2 and medullary thyroid carcinoma. 916 49

The identification of RET proto-oncogene mutations associated with multiple endocrine neoplasia type 2 (MEN-2) has provided a convenient screening test for MEN-2 in patients with pheochromocytoma (PH). In 120 patients with apparently sporadic PH, we analyzed RET exons 10, 11, 13 and 16 using denaturing gradient gel electrophoresis and found a Leu to Phe missense mutation at codon 790 (exon 13) in 1 case. A TaqI polymorphism located at exon 13 and an AluI polymorphism at exon 14 were present with a similar frequency in the 120 sporadic PH and in 94 unaffected normotensive Caucasian subjects. In 60 patients with PH, including 14 with documented MEN-2, we compared genetic testing with the pentagastrin stimulation test. The latter was 100% sensitive and 92% specific, whereas genetic testing was 88% sensitive and 100% specific. Additional somatic mutations were sought in 35 sporadic PH. Two missense mutations affecting RET exons 11 (C634R) and 16 (M918T) and three neutral mutations at codon 836 of exon 14 associated with the AluI polymorphism were detected. Detection of RET mutations in patients with PH is safe, specific and convenient. Tumoral mutations of the RET gene may play a role in medullary tumorigenesis but seem to be less frequent than previously reported.
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PMID:Genetic alterations of the RET proto-oncogene in familial and sporadic pheochromocytomas. 916 62

Hirschsprung disease and the multiple endocrine neoplasia type 2 syndromes are hereditary disorders related to the abnormal migration, proliferation or survival of neural crest cells and their derivatives. Hirschsprung disease is a frequent disorder of the enteric nervous system, resulting in intestinal obstruction. The multiple endocrine neoplasia type 2 syndromes predispose to cancers of neural crest derivatives. Both diseases are associated with heterozygous mutations in the RET proto-oncogene. RET encodes a transmembrane receptor tyrosine kinase expressed in neural crest lineages and whose ligand, glial-cell-line-derived neurotrophic factor, has been very recently identified. In vitro expression studies demonstrate that while Hirschsprung disease mutations result in loss of function of the mutant RET tyrosine kinase, multiple endocrine neoplasia type 2 mutations lead to its constitutive activation. Thus, the two 'faces' of RET, gain of function and loss of function, each lead to a different syndrome, respectively: multiple endocrine neoplasia type 2, a cancer syndrome, or Hirschsprung disease, a developmental defect.
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PMID:RET in human development and oncogenesis. 917 4

Inherited predisposition to phaeochromocytoma (MIM No 171300) occurs in multiple endocrine neoplasia type 2 (MEN 2) (MIM No 171400), von Hippel-Lindau (VHL) disease (MIM No 199300), and neurofibromatosis type 1 (NF1) (MIM No 162200). In addition, familial phaeochromocytoma alone has also been reported and we and others have identified germline VHL mutations in five of six kindreds analysed previously. Germline mutations in the RET proto-oncogene, which encodes a receptor tyrosine kinase, and in the VHL tumour suppressor gene cause MEN 2 and VHL disease, respectively. To further investigate the genetics of phaeochromocytoma predisposition, we analysed three groups of patients with no evidence of VHL disease, MEN 2 or NF1: Group A, eight kindreds with familial phaeochromocytoma; Group B, two patients with isolated bilateral phaeochromocytoma; and Group C, six cases of multiple extra-adrenal phaeochromocytoma or adrenal phaeochromocytoma with a family history of neuroectodermal tumours. Germline missense VHL mutations were identified in three of eight kindreds with familial phaeochromocytoma. A germline VHL mutation was also characterised in one of the two patients with bilateral phaeochromocytoma. No VHL or RET mutations were detected in the final group of patients with multiple extra-adrenal phaeochromocytoma or adrenal phaeochromocytoma with a family history of neuroectodermal tumours. The absence of germline VHL and RET gene mutations in many of these families suggested that other phaeochromoeytoma susceptibility loci may exist. Glial cell line-derived neurotrophic factor (GDNF) has been recently identified as a natural ligand for RET. Thus, it seems plausible that GDNF is a good candidate gene to play a role in phaeochromocytoma susceptibility. We searched for germline mutations in GDNF in 16 cases of familial phaeochromocytoma (groups A, B and C) and looked for evidence of somatic change in GDNF in 28 sporadic phaeochromocytomas, 12 MEN 2 phaeochromocytomas and five VHL phaeochromocytomas. No GDNF mutations were identified in patients with familial phaeochromocytoma disease, but a c277C-->T (R93W) sequence variant was identified in one of 28 sporadic tumours. This candidate mutation was identified in the germline and tumour tissue but was not present in 104 control GDNF alleles. GDNF sequence variants including R93W have been suggested previously to represent low penetrance susceptibility mutations for Hirschsprung disease and the R93W was not identified in 376 control alleles studied by others. These findings suggest that although GDNF mutations do not appear to have a major role in the pathogenesis of familial or sporadic phaeochromocytomas, allelic variation at the GDNF locus may modify phaeochromocytoma susceptibility.
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PMID:Genetic predisposition to phaeochromocytoma: analysis of candidate genes GDNF, RET and VHL. 921 74

Germ-like and somatic mutations in the RET proto-oncogene are associated with inherited and sporadic medullary thyroid carcinoma (MTC). The majority of patients with multiple endocrine neoplasia type 2A (MEN2A) and familial medullary thyroid carcinoma (FMTC) carry germ-line point mutations that result in the substitution of one of five cysteine residues. We investigated exons 10, 11, 13, 14 and 16 of the RET proto-oncogene in 33 unrelated Japanese patients with MTC. Eleven of the 33 cases (33%) were found to have germ-line mutations. Three previously unreported mutations in exon 10 and 11 were identified: one in codon 620, (TGC-->GGC), resulting in a cysteine to glycine substitution, and two in codon 630, (TGC-->TCC) and (TGC-->TAC), resulting in cysteine to serine and cysteine to tyrosine changes, respectively. The new mutations were present in the germ-line DNA of four unrelated patients for whom a family history of MTC had not been documented. Because the new RET alleles described here involve cysteine residues in a region of protein previously associated with FMTC and MEN2A, it is very likely that they represent mutations that predispose to the development of MTC.
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PMID:Novel germline RET proto-oncogene mutations associated with medullary thyroid carcinoma (MTC): mutation analysis in Japanese patients with MTC. 922 75

Mutations in the RET proto-oncogene have recently been recognized to be responsible for the inherited multiple endocrine neoplasia type 2 syndrome. As expected, Greek patients with MEN2 and FMTC carry RET mutations similar to those of other ethnic groups. In those regions of the gene that were analyzed, mutations were detected in six out of six families with classical MEN2A, three out of five of the families with familial MTC, and one case with MEN2B. Presymptomatic screening using DNA analysis has now replaced calcitonin stimulation tests in the offspring of families where the mutation has been characterized. The use of these methods will improve the prognosis in MEN2 patients and will also reduce the psychological burden of risk for a potentially lethal disease on family members.
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PMID:Genetic screening for RET mutations in families with multiple endocrine neoplasia 2 syndromes. 923 92

Multiple endocrine neoplasia type 2A (MEN 2A) and familial medullary thyroid carcinoma (FMTC) are two dominantly inherited disorders caused by germline mutations of the RET proto-oncogene. The RET gene codes for a receptor tyrosine kinase. The majority of MEN2A and FMTC mutations are clustered in the extra-cellular cysteine-rich domain and result in constitutive activation of the tyrosine kinase through the formation of disulfide-bonded RET homodimers. Recently, two novel point mutations have been identified in the germline of five distinct FMTC families. Both mutations occur within the catalytic domain of the RET kinase and lead to the substitution of either glutamic acid 768 or valine 804 by an aspartic acid and a leucine respectively. We have introduced each FMTC mutation in two RET isoforms: RET51 the long isoform (1114 aa) and RET9 the short isoform (1072 aa) which differ in the C-terminal region of the protein. The RET51 isoform carrying either E768D or V804L mutation was autophosphorylated, displayed a transforming activity upon expression in Rat1 fibroblasts and induced neuronal differentiation of PC12 cells. However, the transforming capacity of these RET51-FMTC mutants was found to be severalfold less potent compared to the same isoform carrying either the MEN2A mutation (C634R) or the MEN2B mutation (M918T). In contrast, RET9 containing mutations E768D or V804L was not autophosphorylated, exhibited a poor oncogenic potential in fibroblasts and did not promote neuritic outgrowth upon expression in PC12 cells. Overall, these findings demonstrate that mutations E768D and V804L are gain-of-function mutations that confer to the long RET isoform the capacity to exert a biological effect, although these mutations are more weakly activating than the MEN2A and MEN2B mutations. These results may provide a biochemical basis as to why the phenotypic consequences of these mutations are restricted to thyroid C-cells.
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PMID:Oncogenic activation of RET by two distinct FMTC mutations affecting the tyrosine kinase domain. 924 75

The evolution of cancer is a multistep phenomenon, and multiple cellular genetic lesions are involved in the emergence of the malignant neoplasm. Several early events have been implicated in the neoplastic transformation of thyrocytes, and recent reports have described the involvement of specific genetic alterations in different types of thyroid neoplasms: ras point mutations are frequently observed in tumours with follicular histology, gsp-the mutated form of the alpha subunit of the Gs-protein-is encountered in up to 73% of papillary or follicular thyroid carcinomas, and a high prevalence of p53 point mutations has been found in anaplastic thyroid carcinomas but not in differentiated follicular tumours. More recent studies revealed that the RET proto-oncogene is involved in the oncogenesis of medullary thyroid carcinoma (MTC) and papillary thyroid carcinoma (PTC) by activation of its tyrosine kinase either by point mutation or rearrangement. In this review the most important recently published data on alterations of the RET proto-oncogene in heritable and sporadic MTCs and in PTCs will be summarized. Emphasis will be directed to the pathophysiological mechanisms of tumour initiation, the indications and limitations of DNA testing, and the clinical implications of identified RET defects in thyroid lesions.
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PMID:The RET proto-oncogene in medullary and papillary thyroid carcinoma. Molecular features, pathophysiology and clinical implications. 924 27

MEN (multiple endocrine neoplasia) type 2 syndrome is an inherited disease characterized by medullary thyroid carcinoma, pheochromocytoma, hyperparathyroidism and/or developmental anomalies. Germ-line mutations of the RET proto-oncogene have recently been identified as the underlying cause of the syndrome. Accordingly, several investigators have advocated prophylactic total thyroidectomy for medullary thyroid carcinoma at an early age in MEN 2 gene carriers identified by DNA analysis. Before applying this strategy in Japan, the biological behavior of each category of tumor in MEN 2 syndrome, and medullary thyroid carcinoma in particular, should be well understood. We conducted a nationwide questionnaire survey to clarify the clinicopathological features of MEN 2 in Japan, obtaining data for 230 patients diagnosed as having MEN 2. They included 84 males and 146 females, with a median age of 37.5 years (range 5-83). Patients were categorized as 179 with MEN 2A, 17 with MEN 2B, 12 with familial medullary thyroid carcinoma and 22 'other'. Medullary thyroid carcinoma, pheochromocytoma and parathyroid lesions occurred in 224 (97%), 132 (57%) and 25 (11%) patients respectively. Twelve patients (5.2%) died of medullary thyroid carcinoma and 11 patients died of other or unknown causes. Of 163 patients for whom follow-up data were obtained, 82 (50%) experienced recurrences of medullary thyroid carcinoma, including symptomatic recurrent tumors in 24 patients and elevated calcitonin levels alone in 54. In the era of RET mutational analysis for screening relatives of patients with MEN 2, these data provide useful information about surgical management for patients with MEN 2 in Japan.
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PMID:A nationwide clinical survey of patients with multiple endocrine neoplasia type 2 and familial medullary thyroid carcinoma in Japan. 925 65


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