Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: 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)

The ataxia-telangiectasia-mutated (ATM) kinase is a key transducer of DNA damage signals within the genome maintenance machinery and a tumour suppressor whose germline mutations predispose to familial breast cancer. ATM signalling is constitutively activated in early stages of diverse types of human malignancies and cell culture models in response to oncogene-induced DNA damage providing a barrier against tumour progression. As BRCA1 and BRCA2 are also components of the genome maintenance network and their mutations predispose to breast cancer, we have examined the ATM expression in human breast carcinomas of BRCA1/2 mutation carriers, sporadic cases and familial non-BRCA1/2 patients. Our results show that ATM protein expression is aberrantly reduced more frequently among BRCA1 (33%; P=0.0003) and BRCA2 (30%; P=0.0009) tumours than in non-BRCA1/2 tumours (10.7%). Furthermore, the non-BRCA1/2 tumours with reduced ATM expression were more often estrogen receptor (ER) negative (P=0.0002), progesterone receptor (PR) negative (P=0.004) and were of higher grade (P=0.0004). In our series of 1013 non-BRCA1/2 cases, ATM was more commonly deficient (20%; P=0.0006) and p53 was overabundant (47%; P<0.0000000001) among the difficult-to-treat ER/PR/ERBB2-triple-negative subset of tumours compared with cases that expressed at least one of these receptors (10 and 16% of aberrant ATM and p53, respectively). We propose a model of 'conditional haploinsufficiency' for BRCA1/2 under conditions of enhanced DNA damage in precancerous lesions resulting in more robust activation and hence increased selection for inactivation or loss of ATM in tumours of BRCA1/2 mutation carriers, with implications for genomic instability and curability of diverse subsets of human breast cancer.
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PMID:The DNA damage signalling kinase ATM is aberrantly reduced or lost in BRCA1/BRCA2-deficient and ER/PR/ERBB2-triple-negative breast cancer. 1798 90

The formation of micronuclei (MN) is extensively used in molecular epidemiology as a biomarker of chromosomal damage, genome instability, and eventually of cancer risk. The occurrence of MN represents an integrated response to chromosome-instability phenotypes and altered cellular viabilities caused by genetic defects and/or exogenous exposures to genotoxic agents. The present article reviews human population studies addressing the relationship between genetic polymorphisms and MN formation, and provides insight into how genetic variants could modulate the effect of environmental exposures to genotoxic agents, host factors (gender, age), lifestyle characteristics (smoking, alcohol, folate), and diseases (coronary artery disease, cancer). Seventy-two studies measuring MN frequency either in peripheral blood lymphocytes or exfoliated cells were retrieved after an extensive search of the MedLine/PubMed database. The effect of genetic polymorphisms on MN formation is complex, influenced to a different extent by several polymorphisms of proteins or enzymes involved in xenobiotic metabolism, DNA repair proteins, and folate-metabolism enzymes. This heterogeneity reflects the presence of multiple external and internal exposures, and the large number of chromosomal alterations eventually resulting in MN formation. Polymorphisms of EPHX, GSTT1, and GSTM1 are of special importance in modulating the frequency of chromosomal damage in individuals exposed to genotoxic agents and in unexposed populations. Variants of ALDH2 genes are consistently associated with MN formation induced by alcohol drinking. Carriers of BRCA1 and BRCA2 mutations (with or without breast cancer) show enhanced sensitivity to clastogens. Some evidence further suggests that DNA repair (XRCC1 and XRCC3) and folate-metabolism genes (MTHFR) also influence MN formation. As some of the findings are based on relatively small numbers of subjects, larger scale studies are required that include scoring of additional endpoints (e.g., MN in combination with fluorescent in situ hybridization, analysis of nucleoplasmic bridges and nuclear buds), and address gene-gene interactions.
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PMID:Genetic polymorphisms and micronucleus formation: a review of the literature. 1803 39

Five breast cancer subtypes have been described in sporadic breast cancer (SBC) using expression arrays: basal-like, ERBB2, normal breast-like, luminal A and B. These molecular subtypes show different genomic aberration patterns (GAPs). Recently, our group described these breast cancer subtypes in 50 non-BRCA1/2 familial tumors using immunohistochemistry assays. We extended this study to the other classes of familial breast cancer (FBC), including 62 tumors (18 BRCA1, 16 BRCA2 and 28 non-BRCA1/2), with the same panel of 25 immunohistochemical (IHC) markers and histological grade obtaining a similar classification. We combined these data with results generated by a 1 Mb BAC array-based CGH study to evaluate the genomic aberrations of each group. We found that BRCA1-related tumors are preferentially basal-like, whereas non-BRCA1/2 familial tumors are mainly luminal A subtype. We described distinct GAPs related to each IHC subtype. Basal tumors had a greater number of gains/losses, while luminal B tumors had more high-level DNA amplifications. Our data are similar to those obtained in SBC studies, highlighting the existence of distinct genetic pathways of tumor evolution, common to both SBC and FBC.
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PMID:Distinct genomic aberration patterns are found in familial breast cancer associated with different immunohistochemical subtypes. 1807 13

BRCA2 is a multifunctional tumor suppressor protein which plays critical roles in DNA repair, transcription, and cell proliferation, and the loss of which has been linked to the biology of several types of cancers. Here, on prostate adenocarcinoma specimens from 80 patients, we demonstrate that BRCA2 protein is lost in carcinoma cells compared to normal and hyperplastic prostate epithelium. Using highly metastatic prostate cancer PC-3 cells, we show that while BRCA2 depletion by small-interfering RNA promoted migration onto the extracellular matrix proteins fibronectin, laminin, and collagens, as well as invasion through the reconstituted basement membrane matrix Matrigel by more than 140%, recombinant BRCA2 overexpression decreased both phenomena by 57-80% and changed cell morphology from angular and spindle to round and compact. The BRCA2 inhibitory effect on cancer cell migration and invasion resulted from down-regulation of matrix metalloproteinase (MMP)-9 protein levels due to increased MMP-9 proteolysis, and was signaled through inhibition of PI3-kinase/AKT and activation of MAPK/ERK pathway. In BRCA2-overexpressing PC-3 cells, transient transfection with a constitutively active PI3-kinase mutant or treatment with the MAPK/ERK inhibitor PD98059 rescued MMP-9 levels and restored the migratory and invasive capabilities. Consistently, PI3-kinase inhibition with a dominant-negative mutant or MAPK/ERK activation with a gain-of-function mutant reduced MMP-9 levels and prevented migration and invasion in wild-type PC-3 cells. These results provide novel evidence showing that a functional BRCA2 protein may limit the metastatic potential of neoplastic cells by down-regulating MMP-9 production through inhibition of PI3-kinase/AKT and activation of MAPK/ERK, effectively hindering cancer cell migration and invasion.
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PMID:Loss of BRCA2 promotes prostate cancer cell invasion through up-regulation of matrix metalloproteinase-9. 1816 27

Most familial breast cancers arise in patients who tested negative for germline mutations in BRCA1 and BRCA2 genes (also referred to as BRCAX cases). Several studies aimed to define histopathological and molecular profiles characteristic of BRCA1, BRCA2 and BRCAX tumors have been performed. Major pathological and immunohistochemical differences have been reported in BRCA1 cancers compared to the other two groups, whereas less difference has been observed between BRCA2 and BRCAX cases. The aim of this study was to investigate the ability of selected tumor markers to discriminate BRCAX breast cancers from cancers arising in carriers of mutations in BRCA genes, and their usefulness in selecting familial cases in whom testing for such mutations is more likely to result uninformative. We carried out a morphological and immunohistochemical analysis on 22 BRCA1, 16 BRCA2 and 33 BRCAX familial breast cancers. Age at first diagnosis, histological type and grade, and immunostaining for estrogen receptor (ER), progesterone receptor (PR), p53, HER2/Neu, E-cadherin and cyclin D1 were investigated. The occurrence of somatic mutations of the TP53 gene was also verified. BRCA1 tumors resulted clearly distinguishable from BRCAX cases, occurring at a younger age, being more frequently of higher grade, negative for ER, PR and cyclin D1 expression and positive for p53 alterations. The predictive value of age at diagnosis, histological grade and PR expression was confirmed in a multivariable analysis. When comparing BRCA2 with BRCAX tumors, the only parameter that differed was cyclin D1, which was significantly overexpressed in BRCA2 cases both in the univariable and the multivariable analyses. If confirmed by further studies, our observations indicate that the investigation of cyclin D1 expression in familial breast cancer cases could be used, in conjunction with the analysis of other tumor markers preferentially associated with BRCA1 or BRCA2 tumors, to prioritize hereditary cases for mutation testing in BRCA genes.
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PMID:Cyclin D1 expression analysis in familial breast cancers may discriminate BRCAX from BRCA2-linked cases. 1832 10

Germline mutations in BRCA1 and BRCA2 confer high risks of breast cancer. However, evidence suggests that these risks are modified by other genetic or environmental factors that cluster in families. A recent genome-wide association study has shown that common alleles at single nucleotide polymorphisms (SNPs) in FGFR2 (rs2981582), TNRC9 (rs3803662), and MAP3K1 (rs889312) are associated with increased breast cancer risks in the general population. To investigate whether these loci are also associated with breast cancer risk in BRCA1 and BRCA2 mutation carriers, we genotyped these SNPs in a sample of 10,358 mutation carriers from 23 studies. The minor alleles of SNP rs2981582 and rs889312 were each associated with increased breast cancer risk in BRCA2 mutation carriers (per-allele hazard ratio [HR] = 1.32, 95% CI: 1.20-1.45, p(trend) = 1.7 x 10(-8) and HR = 1.12, 95% CI: 1.02-1.24, p(trend) = 0.02) but not in BRCA1 carriers. rs3803662 was associated with increased breast cancer risk in both BRCA1 and BRCA2 mutation carriers (per-allele HR = 1.13, 95% CI: 1.06-1.20, p(trend) = 5 x 10(-5) in BRCA1 and BRCA2 combined). These loci appear to interact multiplicatively on breast cancer risk in BRCA2 mutation carriers. The differences in the effects of the FGFR2 and MAP3K1 SNPs between BRCA1 and BRCA2 carriers point to differences in the biology of BRCA1 and BRCA2 breast cancer tumors and confirm the distinct nature of breast cancer in BRCA1 mutation carriers.
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PMID:Common breast cancer-predisposition alleles are associated with breast cancer risk in BRCA1 and BRCA2 mutation carriers. 1835 72

Pleomorphic lobular carcinomas (PLC) of the breast display histological features associated with classic invasive lobular carcinoma (ILC), yet they also exhibit more conspicuous nuclear atypia and pleomorphism, and an aggressive clinical behaviour. From a breast cancer progression perspective, it is unclear whether PLC is a variant of ILC or is a high-grade invasive ductal carcinoma (IDC) that has lost E-cadherin. The molecular features of 26 PLC were studied using immunohistochemistry [oestrogen receptor (ER), progesterone receptor (PR), HER2, p53 and E-cadherin], 0.9 Mb resolution, microarray-based comparative genomic hybridization (aCGH), fluorescent (FISH) and chromogenic (CISH) in situ hybridization and loss of heterozygosity. Comparative analysis was performed with aCGH data from PLC with classic ILC (16 cases) and high grade IDC (35 cases). PLCs were frequently ER- and PR-positive, E-cadherin-negative and occasionally HER2- and p53-positive. Recurrent copy number changes identified by aCGH included gains on 1q, 8q, 11q, 12q, 16p and 17q and losses on 8p, 11q, 13q, 16q and Xq. Highly recurrent 1q+ (100% of cases), 16p+ (93%), 11q- (53%) and 16q- (93%) and evidence of the der(1;16)/der(16)t(1;16) rearrangement, as detected by FISH, suggested that PLC had a 'lobular genotype'. Focal amplifications were evident at 8p12-p11, 8q24, 11q13.1-q14.1, 12q14, 17q12 and 20q13. Loss of BRCA2 was detected in 40% of PLC by LOH. Comparative analysis of aCGH data suggested the molecular features of PLC (ER/PR-positive, E-cadherin-negative, 1q+, 11q(-), 16p+ and 16q(-)) were more closely related to those of ILC than IDC, implicating an overlapping developmental pathway for these lobular tumour types. Molecular alterations found in PLC that are more typical of high-grade IDC than ILC (p53 and HER2 positivity, 8q+, 17q24-q25+, 13q(-) and amplification of 8q24, 12q14, 17q12 and 20q13) are likely to drive the high-grade and more aggressive biology of PLC.
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PMID:Molecular profiling pleomorphic lobular carcinomas of the breast: evidence for a common molecular genetic pathway with classic lobular carcinomas. 1847 30

Hereditary cancer syndromes comprise approximately 5-10% of diagnosed carcinomas. They are caused by mutations in specific genes. Carriers of mutations in these genes are at an increased risk of developing cancer at a young age. When there is a suspicion of a hereditary cancer predisposition syndrome a detailed family tree of the patient requesting screening is constructed. DNA is isolated from all available members of the family. Mutation detection is carried out on DNA from an affected family member. If a mutation is found the remaining family is screened. The genetic basis of a large number of inherited cancer predisposition syndromes is known. In this paper the focus is on mutations in genes responsible for colorectal cancer, meaning adenomatous polyposis coli (APC), which is involved in familial adenomatous polyposis and homo sapiens mutL homolog 1 (hMLH1) and homo sapiens mutS homolog 2 (hMSH2), involved in hereditary non-polyposis colorectal cancer. In addition, the genes responsible for inherited breast and/or ovarian cancer, breast cancer genes 1 and 2 (BRCA1 and BRCA2), and the rearranged during transfection protooncogene RET which is responsible for multiple endocrine neoplasia type 2 are discussed. In all cases emphasis is given to the data available on the Greek population.
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PMID:Inherited cancer predisposition syndromes in Greece. 1850 76

Hereditary breast cancer arising in carriers of mutations in the BRCA1 and BRCA2 genes differs from sporadic breast cancer and from non-BRCA1/2 familial breast carcinomas. Most BRCA1 carcinomas have the basal-like phenotype and are high-grade, highly proliferating, estrogen receptor-negative and HER2-negative breast carcinomas, characterized by the expression of basal markers such as basal keratins, P-cadherin and epidermal growth factor receptor. BRCA1 carcinomas frequently carry p53 mutations. The basal-like phenotype is only occasionally found in BRCA2 carcinomas, which tend to be estrogen and progesterone receptor positive. BRCA1 and BRCA2 loss of heterozygosity is found in almost all BRCA1 and BRCA2 carcinomas, respectively. Both genotypes have a low frequency of HER2 expression/amplification. In addition, comparative genomic hybridization and array expression studies have revealed differences in chromosomal gains and losses as well as expression patterns between genotypes. Several studies have shown that hereditary carcinomas that are not attributable to BRCA1/2 mutations are heterogeneous and have phenotypic similarities to BRCA2 tumors. A small group of cases are secondary to mutations in other breast cancer susceptibility genes, such as p53, PTEN or CDH1. As a result of the low frequency of breast carcinomas attributable to mutations in these genes, it is very difficult to establish a specific phenotype for each genotype, other than the association of lobular carcinomas with CDH1 germline mutations. The pathological and molecular features of hereditary breast cancer can drive specific treatments and influence the process of mutation screening.
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PMID:The molecular pathology of hereditary breast cancer. 1854 63

Germline mutations in BRCA1 account for a low proportion of hereditary cases in diverse populations. Several efforts have been made to find new genes involved in the inheritance of breast cancer with no success until today. The participation of BRCA1 in the development of breast cancer has been proposed in several studies where hypermethylation of its promoter and a decrease in expression has been reported for sporadic cases and one study on familial cases. To explore the participation of BRCA1 in hereditary carcinogenesis through a different mechanism than the inheritance of germline mutations, we studied the methylation status of its promoter in breast tumors, from patients previously screened for BRCA1/BRCA2 germline mutations. We also determined the presence of the BRCA1 protein in these tumors and correlated both events with tumor grade, hormone receptors and ERBB2 presence. Promoter hypermethylation of the BRCA1 gene was detected in 51% of our biopsies, among which 67% did not express the respective protein. This result leads us to suggest that hypermethylation could be considered as an inactivating mechanism for BRCA1 expression, either as a first or second hit. Moreover, a number of biopsies with absence of expression on BRCA1 showed negative detection of estrogen and progesterone receptors, a similar phenotype to BRCA1 mutated breast tumors.
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PMID:Promoter hypermethylation of BRCA1 correlates with absence of expression in hereditary breast cancer tumors. 1856 44


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