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

Most cervical carcinomas appear to arise from cervical intraepithelial neoplasia (CIN) lesions. In addition to infection with high-risk human papilloma viruses, which is indicative of an increased risk of progression, alterations of oncogenes and tumor suppressor genes play a role. Genetic studies of CIN lesions, primary cervical carcinoma, and metastases may shed light on the relative importance of various genetic alterations involved in the progression of CIN to invasive carcinoma. We examined tumor material from 10 patients with squamous cell carcinoma of the uterine cervix and synchronous CIN lesions and lymph node metastases. The CIN component, invasive carcinoma, and lymph node metastases were analyzed separately for loss of heterozygosity (LOH) on the following loci: VHL (3p21), HLA region (6p22-23), PGL (11q 22-24), E6 associated protein (15q11-13), TP53 (17p13), DCC (18q21.1), and chromosomes 1, 2, 4, 9, 20, and X. Using immunohistochemistry, the expression of the EGF receptor, ERBB2, and TP53 was determined. In CIN lesions, frequent LOH was found at chromosome arms 3p, 6p, and 11q. Primary invasive carcinoma showed additional LOH at chromosome arms 6q, 17p, and 18q. In lymph node metastases, an additional locus on the X chromosome displayed LOH. All carcinomas and synchronous lesions but one showed high expression levels of the EGF receptor. TP53 staining, when present, was found in all synchronous lesions. Focal staining of ERBB2 was found in one CIN lesion, two invasive carcinomas, and four metastases. The molecular alterations accumulated in a fashion that paralleled the progression of the tumors. These results indicate that cervical tumorigenesis occurs in a stepwise fashion, including infection and integration of oncogenic HPV and several specific genetic alterations. Genes Chromosomes Cancer 26:346-354, 1999.
 ...
PMID:Genetic alterations during the progression of squamous cell carcinomas of the uterine cervix. 1053 70

We here review the literature on genetics related to pheochromocytoma. About 10 percent of these neuroendocrine tumors are hereditary and are most often associated with multiple endocrine neoplasia type 2 (MEN 2), von Hippel-Lindau disease, and neurofibromatosis type 1 (NF 1). Hereditary tumor syndromes such as the aforementioned ones, are ideal to study the molecular pathogenesis of tumorigenesis as opposed to sporadic tumors in which genetic alterations often merely represent epigenetic tumor progression phenomena. Recent advances in molecular genetics, especially of RET, VHL, NF1, and SDHD, helped better understand the pathogenesis of pheochromocytoma. In this paper, we not only summarize key points of genetic discoveries related to pheochromocytoma, but also report in table format all known RET germline mutations related to pheochromocytoma.
 ...
PMID:Genetic aspects of pheochromocytoma. 1130 96

The pheochromocytomas are an important cause of secondary hypertension. Although pheochromocytoma susceptibility may be associated with germline mutations in the tumor-suppressor genes VHL and NF1 and in the proto-oncogene RET, the genetic basis for most cases of nonsyndromic familial pheochromocytoma is unknown. Recently, pheochromocytoma susceptibility has been associated with germline SDHD mutations. Germline SDHD mutations were originally described in hereditary paraganglioma, a dominantly inherited disorder characterized by vascular tumors in the head and the neck, most frequently at the carotid bifurcation. The gene products of two components of succinate dehydrogenase, SDHC and SDHD, anchor the gene products of two other components, SDHA and SDHB, which form the catalytic core, to the inner-mitochondrial membrane. Although mutations in SDHC and in SDHD may cause hereditary paraganglioma, germline SDHA mutations are associated with juvenile encephalopathy, and the phenotypic consequences of SDHB mutations have not been defined. To investigate the genetic causes of pheochromocytoma, we analyzed SDHB and SDHC, in familial and in sporadic cases. Inactivating SDHB mutations were detected in two of the five kindreds with familial pheochromocytoma, two of the three kindreds with pheochromocytoma and paraganglioma susceptibility, and 1 of the 24 cases of sporadic pheochromocytoma. These findings extend the link between mitochondrial dysfunction and tumorigenesis and suggest that germline SDHB mutations are an important cause of pheochromocytoma susceptibility.
 ...
PMID:Gene mutations in the succinate dehydrogenase subunit SDHB cause susceptibility to familial pheochromocytoma and to familial paraganglioma. 1140 20

Approximately 10% of catecholamine-secreting tumors are malignant, and 10% are familial. These tumors have been associated with several hereditary syndromes, including multiple endocrine neoplasia type 2, von Hippel-Lindau syndrome, neurofibromatosis type 1, and familial paraganglioma. Mutations in succinate dehydrogenase (SDH) subunit genes have been identified in some kindreds with catecholamine-secreting tumors. In 1972 at the Mayo Clinic, a metastatic catecholamine-secreting paraganglioma was diagnosed in a 32-yr-old man. In 1979, 7 yr after the initial surgical treatment, a lytic metastasis to the left femur was found and was treated with local external radiotherapy. Locally metastatic abdominal catecholamine-secreting paragangliomas were diagnosed in the patient's 27-yr-old son. Analyses of the VHL, RET, SDHD, and SDHC genes revealed no mutations. However, a missense point mutation was detected in the SDHB gene: c.725G-->A in exon 7, which alters a conserved arginine at amino acid position 242 to a histidine (R242H). Sequencing of the SDHB gene in the tumors did not reveal any somatic mutations or loss of heterozygosity of the remaining allele. Thirty years after the initial diagnosis, the father is one of the longest living survivors of malignant catecholamine-secreting paraganglioma. Our findings indicate that mutations in SDHB may be associated with metastatic, yet clinically indolent, abdominal paraganglioma in some families.
 ...
PMID:Familial malignant catecholamine-secreting paraganglioma with prolonged survival associated with mutation in the succinate dehydrogenase B gene. 1221 55

We review genetic aspects and recent advances in our understanding of the molecular pathogenesis of familial chromaffin cell tumors (pheochromocytoma, paraganglioma). About 10 percent of pheochromocytomas are familial and occur as part of multiple endocrine neoplasia type 2 (MEN 2), von Hippel-Lindau (VHL) disease, and neurofibromatosis type 1 (NF 1). A subset of paragangliomas, tumors that can also produce and secrete catecholamines, are also familial and occur in patients with germline mutations in genes that encode subunits of the mitochondrial complex II. The precise molecular mechanisms underlying the pathogenesis of chromaffin cell tumors remain widely unknown, although recent studies in hereditary tumors help elucidate their development. In MEN 2, overrepresentation of mutant RET in selected adrenomedullary cells may be an important mechanism in initiating the formation of a pheochromocytoma. In VHL disease, pheochromocytoma development appears to occur according to Knudson's two-hit model, a VHL germline mutation and wildtype allelic deletion. Tumorigenesis of NF1-associated pheochromocytomas remains unknown, as does tumor formation (i.e., carotid body tumor) in patients with germline mutations in SDHB, SDHC, and SDHD, genes that encode subunits of the mitochondrial complex II, the smallest complex in the respiratory chain. Many genetic alterations have been found in sporadic chromaffin cell tumors. However, at present such genetic changes are difficult to place into context with regard to tumor formation and progression.
 ...
PMID:New insights into the genetics of familial chromaffin cell tumors. 1238 38

Phaeochromocytomas arising in adrenal or extra-adrenal sites and paragangliomas of the head and neck, in particular of the carotid bodies, occur sporadically and also in a familial setting. In addition to mutations in RET and VHL in familial disease, germline mutations in SDHD and SDHB genes that encode subunits of mitochondrial complex II have also been associated with the development of familial phaeochromocytomas. To further investigate the role of SDHD and SDHB in the development of these tumours we determined the occurrence of germline SDHD and SDHB mutations in four patients with a family history of phaeochromocytoma with associated head and neck paraganglioma, one patient with a family history of phaeochromocytoma only and two patients with apparently sporadic extra-adrenal phaeochromocytoma, one of whom had early onset disease. Secondly, we investigated whether somatic SDHB mutations correlated with loss of heterozygosity at 1p36 in a subgroup of 11 sporadic and three MEN 2-associated RET-mutation-positive phaeochromocytomas. Novel SDHB mutations were identified in the probands from four families and two apparently sporadic cases (six of seven probands studied), including two missense mutations, a single nonsense and frameshift mutation, as well as two splice site mutations, one of which was shown to have partial penetrance resulting in 'leaky' splicing. Further, five intronic polymorphisms in SDHB were found. No SDHD mutations were identified. In addition, no somatic SDHB mutations were found in the remaining allele of the 11 sporadic adrenal phaeochromocytomas with allelic loss at 1p36 or the three MEN 2-associated RET-mutation-positive phaeochromocytomas. Therefore, we conclude that SDHB has a major role in the pathogenesis of familial phaeochromocytomas, but the possible role of SDHB in sporadic tumours showing allelic loss at 1p36 has yet to be ascertained.
 ...
PMID:Novel succinate dehydrogenase subunit B (SDHB) mutations in familial phaeochromocytomas and paragangliomas, but an absence of somatic SDHB mutations in sporadic phaeochromocytomas. 1261 61

Pheochromocytomas and paragangliomas are tumors of the autonomic nervous system; pheochromocytomas are tumors of the adrenal medulla, and paragangliomas are extra-adrenal tumors arising from either the sympathetic nervous system or parasympathetic ganglia. It has previously been estimated that approximately 10%-15% of pheochromocytomas are due to hereditary causes. However, our increased understanding of the three hereditary syndromes (neurofibromatosis 1, multiple endocrine neoplasia type 2, and von Hippel-Lindau syndrome) in which pheochromocytoma is found and the recent discovery that mutations in genes in the succinate dehydrogenase family (SDHB and SDHD) predispose to pheochromocytoma have necessitated a re-evaluation of the genetic basis of pheochromocytoma. These studies indicate that the frequency of germline mutations associated with isolated pheochromocytoma is higher than previously estimated, with both hospital-based series and a large population-based series indicating that the frequency of germline mutations in RET, VHL, SDHB, and SDHD taken together approximates 20%. In all patients with pheochromocytoma, including those with known hereditary syndrome or a positive family history, the frequency of germline mutations in these four genes together approaches 30%. Given the frequency of germline mutations, consideration should be given to genetic counseling for all patients with pheochromocytoma and is particularly important for individuals with a positive family history, multifocal disease, or a diagnosis before age 50. Identification of patients with hereditary pheochromocytoma is important because it can guide medical management in mutation-positive patients and their families. This review provides an overview of the known genetic syndromes that are commonly associated with pheochromocytoma, examines recent data on the association of germline mutations in the succinate dehydrogenase gene family with pheochromocytoma, and suggests guidelines for the genetic evaluation of pheochromocytoma patients.
 ...
PMID:Pheochromocytoma: the expanding genetic differential diagnosis. 1292 44

Germ-line mutations in the genes encoding succinate dehydrogenase complex subunits B (SDHB) and D (SDHD) have been reported in familial paragangliomas and apparently sporadic phaeochromocytomas (ASP), but the genotype-phenotype relationships of these mutations are unknown. Eighty-four patients (all but 2 followed up for 8.8 +/- 5.7 years) with ASP (57 with adrenal tumors, 27 with extra-adrenal, multiple, malignant, or recurrent tumors) were screened for the major susceptibility genes for phaeochromocytoma (RET, VHL, SDHD, and SDHB). Thirty-three tumors were available for molecular analysis, enzyme assays, and immunohistochemistry. No (0%) RET and 2 (2.4%) VHL mutations were detected. Only two coding single nucleotide polymorphisms in the SDHD gene (G12S and H50R) were found in 6 patients (7%). Conversely, six deleterious mutations in the SDHB gene were identified in 8 patients (9.5%). Ectopic site and recurrence or malignancy were strongly associated with SDHB mutations (7 of 8, 87%, versus 20 of 76, 26%; P = 0.001). Somatic DNA analysis indicated a loss of heterozygosity at chromosome 1p36 (SDHB locus) in 16 of 33 cases (48%). A loss of heterozygosity at the SDHB locus was found in all tumors with SDHB mutation, and assays of respiratory chain enzymes showed a complete loss of complex II catalytic activity. The vascular architecture of tumors with SDHB mutations displayed features typical of malignancy. These data strongly suggest that SDHB gene is a tumor suppressor gene and that the identification of germ-line mutations in SDHB gene in patients with ASPs should be considered as a high-risk factor for malignancy or recurrence.
 ...
PMID:Mutations in the SDHB gene are associated with extra-adrenal and/or malignant phaeochromocytomas. 1450 Apr 3

Approximately 75% of pheochromocytomas are sporadic. Germline mutations in RET, VHL, SDHB, and SDHD have been shown to cause the 25% that are hereditary. Germline high penetrance gain-of-function RET mutations cause multiple endocrine neoplasia type 2, of which medullary thyroid carcinoma (MTC) and pheochromocytoma are components, whereas loss-of-function mutations cause Hirschprung disease (HSCR). A low-penetrance founder locus, in linkage disequilibrium with a RET ancestral haplotype comprising specific alleles at three intron (IVS) 1 single nucleotide polymorphisms (SNPs) (haplotype 0) and SNP A45A, predisposes to the majority of isolated HSCR. A different low-penetrance locus, in linkage disequilibrium with IVS 1 haplotype 2 and SNP S836S, was associated with a subset of sporadic MTC. We, therefore, sought to determine whether RET might also be a low-penetrance gene for apparently sporadic pheochromocytoma. We analyzed 104 pheochromocytoma cases without germline mutations in RET, VHL, SDHD, and SDHB for their status at A45, S836, three IVS 1 SNPs, and a novel upstream insertion/deletion variant. Pheochromocytoma cases were not associated with either A45A or S836S, but we found that cases were associated with haplotype 0 (P = 0.032). However, unlike HSCR, this pheochromocytoma-associated haplotype 0 was not associated with A45A. Taken together with the strengthening of association with the addition of the 5' insertion/deletion variant data (P = 0.016), our observations suggest the presence of a low-penetrance pheochromocytoma susceptibility locus in a region upstream of the putative loci for HSCR and apparently sporadic MTC.
 ...
PMID:Intronic single nucleotide polymorphisms in the RET protooncogene are associated with a subset of apparently sporadic pheochromocytoma and may modulate age of onset. 1455 73

C cell hyperplasia is associated with medullary carcinoma of the thyroid in the inherited MEN2 syndromes, in which the great majority of cases have been shown to be due to a mutation in the RET oncogene. We report a study of a family with C cell hyperplasia and hypercalcitoninemia in which no cases of medullary carcinoma have yet occurred and which lacked an identifiable causative RET mutation. Four of the family members showed hypercalcitoninemia, and marked C cell hyperplasia was present in each of the three in whom thyroidectomy has been performed. We investigated the possible involvement of the SDHD gene, because somatic and germline mutations in this gene have been found in a variety of tumors of neural crest-derived tissue. A germline mutation in exon 2 of the SDHD gene (c149 A-G, His 50 Arg) was found in six members of the family; all the four available members with hypercalcitoninemia possessed the mutation. One of the five available members without hypercalcitoninemia, an 18-yr-old female, also showed the mutation. We conclude that we have identified a new syndrome, characterized by familial non-RET C cell hyperplasia. Our studies suggest that a mutation in SDHD may be causative. These observations have implications for apparently incidental cases of hypercalcitoninemia or C cell hyperplasia.
 ...
PMID:Germline succinate dehydrogenase subunit D mutation segregating with familial non-RET C cell hyperplasia. 1455 76


1 2 3 4 5 6 7 8 9 10 Next >>