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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)
Female rats of the inbred strain BDII are genetically predisposed to endometrial estrogen-dependent adenocarcinomas (EAC). More than 90% of them spontaneously develop this tumor type before the age of 24 months. In order to dissect out the genetic components behind these tumors we have made crosses between BDII females and rats from 2 other strains that are nonsusceptible to EAC. It was found that EAC tumors developed in a subset of intercross and backcross animals from both interstrain crosses. The chromosomal changes in the developing tumors were studied using cytogenetic and molecular cytogenetic methods. From these studies, we conclude that certain chromosome regions were recurrently engaged in chromosomal changes such as increases in copy number (e.g., trisomy, amplification) or decreases (e.g., deletion). Based on the analysis of 56 tumors, 8 regions were found to be particularly often involved: RNO4prx, gain=34 (61%) (amplification 12 cases); RNO5mid, loss=15 (27%); RNO6prx, gain=25 (45%) (amplification 8 cases); RNO10 loss, prx-mid/gain dst=25 (45%) (amplification 1 case); RNO12q, gain=23 (41%); RNO15p loss/RNO15q gain=29 (52%) (amplification 1 case) [RNO, rat chromosome; prx, proximal; mid, middle; dst, distal; p, short arm; q, long arm]. We begun to analyze these regions in detail using various molecular methods and within them there are certain possible target genes, such as
MET
(RNO4q21), CDKN2A/2B (RNO5q32),
MYCN
(RNO6q15 approximately q16), and TP53 (RNO10q24 approximately q25), but it is clear that several other genes, still unidentified, must also be involved.
...
PMID:Cytogenetic aberrations in spontaneous endometrial adenocarcinomas in the BDII rat model as revealed by chromosome banding and comparative genome hybridization. 1589 83
Neuroblastoma is a common childhood tumor comprising cases with rapid disease progression as well as spontaneous regression. Although numerous prognostic factors have been identified, risk evaluation in individual patients remains difficult. To define a reliable prognostic predictor and gene signatures characteristic of biological subgroups, we performed mRNA expression profiling of 68 neuroblastomas of all stages. Expression data were analysed using support vector machines (SVM-rbf), prediction analysis of microarrays (PAM), k-nearest neighbors (k-NN) algorithms and multiple decision trees. SVM-rbf performed best of all methods, and predicted recurrence of neuroblastoma with an accuracy of 85% (sensitivity 77%, specificity 94%). PAM identified a classifier of 39 genes reliably predicting outcome with an accuracy of 80%. In comparison, conventional risk stratification based on stage, age and
MYCN
-status only reached a predictive accuracy of 64%. Kaplan-Meier analysis using the PAM classifier indicated a 5-year survival of 20 versus 78% for patients with unfavorably versus favorably predicted neuroblastomas, respectively (P = 0.0001). Significance analysis of microarrays (SAM) identified additional genes differentially expressed among subgroups.
MYCN
-amplification and high expression of
NTRK1
/TrkA demonstrated a strong association with specific gene expression patterns. Our data suggest that microarray-derived data in addition to traditional clinical factors will be useful for risk assessment and defining biological properties of neuroblastoma.
...
PMID:Prediction of clinical outcome and biological characterization of neuroblastoma by expression profiling. 1610 81
Deletions of the short arm of chromosome 3 are often observed in a specific subset of aggressive neuroblastomas (NBs) with loss of distal 11q and without
MYCN
amplification. The critical deleted region encompasses the locus of the von Hippel-Lindau gene (VHL, 3p25). Constitutional loss of function mutations in the VHL gene are responsible for the VHL syndrome, a dominantly inherited familial cancer syndrome predisposing to a variety of neoplasms, including pheochromocytoma. Pheochromocytomas are, like NB, derived from neural crest cells, but, unlike NB, consist of more mature chromaffin cells instead of immature neuroblasts. Further arguments for a putative role of VHL in NB are its function as oxygen sensitizer and the reported relation between hypoxia and dedifferentiation of NB cells, leading to a more aggressive phenotype. To test the possible involvement of VHL in NB, we did mRNA expression analysis and sought evidence for VHL gene inactivation. Although no evidence for a classic tumor suppressor role for VHL in NB could be obtained, a strong correlation was observed between reduced levels of VHL mRNA and low patient survival probability (p=0.013). Furthermore, VHL appears to have predictive power in
NTRK1
(
TRKA
) positive tumor samples with presumed favorable prognosis, which makes it a potentially valuable marker for more accurate risk assessment in this subgroup of patients. The significance of the reduced VHL expression levels in relation to NB tumor biology remains unexplained, as functional analysis demonstrated no clear effect of the reduction in VHL mRNA expression on protein stability of its downstream target hypoxia-inducible factor alpha.
...
PMID:The von Hippel-Lindau tumor suppressor gene expression level has prognostic value in neuroblastoma. 1650 18
To identify oncogene amplification involved in ovarian carcinogenesis, we studied 21 ovarian carcinomas and 5 serous borderline tumors using conventional comparative genomic hybridization (CGH) and CGH to a genomic DNA microarray. Immunohistochemical analysis of the proteins encoded by the genes that were amplified frequently (FGF3/4,
FGFR1
, CCNE1, PAK1, JUNB, and MDM2) was performed on a tissue microarray comprising 254 cases of ovarian neoplasms. Regarding histologic type, characteristic patterns of copy number changes were revealed. They correlated with histologic tumor type and with intratumoral heterogeneity. Gain of FGF3/4 and CCNE1 was found in all serous carcinomas. Endometrioid carcinomas most frequently showed gain of JUNB (83%), KRAS2 (67%),
MYCN
(50%), ESR (50%), and CCND2 (50%). Of the serous borderline tumors, 80% harbored amplification of
FGFR1
and MDM2 and a 75% gain of PIK3CA. Only CCNE1 immunoreactivity was significantly correlated with CGH results (P < .05) and postoperative survival (P < .05). Microarray-based genomic analysis in combination with immunohistochemical analysis was found to be a powerful technique for identification of clinically relevant gene amplification in human ovarian cancer.
...
PMID:Analysis of gene amplification and prognostic markers in ovarian cancer using comparative genomic hybridization for microarrays and immunohistochemical analysis for tissue microarrays. 1675 89
Tumor suppressor genes can be inactivated by various mechanisms, including promoter hypermethylation and loss of heterozygosity. We screened the 10q locus for loss of heterozygosity and the promoter methylation status of PTEN, MGMT, MXI1, and
FGFR2
in neuroblastic tumors and neuroblastoma cell lines. Expression of these genes in cell lines was analyzed with reverse transcriptase-polymerase chain reaction. Loss of heterozygosity at 10q was detected in 18% of tumors and microsatellite instability in 14%. Promoter hypermethylation of MGMT appeared in 8% of tumors and 25% of cell lines. Correlation between methylation status and lack of expression was evident for PTEN,
FGFR2
, and MXI1 and was less clear for MGMT. No associations between these alterations and
MYCN
amplification, 1p deletion, or aggressive tumor histology could be demonstrated, singly or in combination. These data suggest that 10q alterations might be implicated in the development of a small number of neuroblastomas.
...
PMID:Loss of heterozygosity and microsatellite instability on chromosome arm 10q in neuroblastoma. 1735 Apr 60
For decades, cytogenetic studies have demonstrated that somatically acquired structural rearrangements of the genome are a common feature of most classes of human cancer. However, the characteristics of these rearrangements at sequence-level resolution have thus far been subject to very limited description. One process that is dependent upon somatic genome rearrangement is gene amplification, a mechanism often exploited by cancer cells to increase copy number and hence expression of dominantly acting cancer genes. The mechanisms underlying gene amplification are complex but must involve chromosome breakage and rejoining. We sequenced 133 different genomic rearrangements identified within four cancer amplicons involving the frequently amplified cancer genes MYC,
MYCN
, and
ERBB2
. The observed architectures of rearrangement were diverse and highly distinctive, with evidence for sister chromatid breakage-fusion-bridge cycles, formation and reinsertion of double minutes, and the presence of bizarre clusters of small genomic fragments. There were characteristic features of sequences at the breakage-fusion junctions, indicating roles for nonhomologous end joining and homologous recombination-mediated repair mechanisms together with nontemplated DNA synthesis. Evidence was also found for sequence-dependent variation in susceptibility of the genome to somatic rearrangement. The results therefore provide insights into the DNA breakage and repair processes operative in somatic genome rearrangement and illustrate how the evolutionary histories of individual cancers can be reconstructed from large-scale cancer genome sequencing.
...
PMID:Architectures of somatic genomic rearrangement in human cancer amplicons at sequence-level resolution. 1767 64
MYCN
amplification is associated with poor prognosis in neuroblastoma disease. To improve our understanding of the influence of the
MYCN
amplicon and its corresponding expression, we investigated the 2p expression pattern of
MYCN
amplified (n = 13) and nonamplified (n = 4) cell lines and corresponding primary tumors (n = 3) using the comparative expressed sequence hybridization technique. All but one
MYCN
amplified cell line displayed overexpression at 2p. Expression peaks were observed frequently at 2pter and less frequently at 2p24 (
MYCN
locus), 2p23.3-23.2, and/or 2p23.1. Importantly, cell lines and two corresponding primary tumors displayed expression peaks at similar loci. No significant 2p24 expression level was observed for those cell lines displaying a low amplification rate (n = 3) by comparative genomic hybridization. Only the cell lines with an enhanced peak at 2p23.2-23.3 displayed coamplification of the
ALK
gene (2p23.2), reported to be associated with unfavorable prognosis. Finally, two of four cell lines without
MYCN
amplification, both derived from patients with poor outcome, also showed an expression peak at 2p23.2. These data indicate that, besides
MYCN
, other genes proximal and distal to
MYCN
are highly expressed in neuroblastoma. The prognostic significance of expression peaks at 2p23.2-23.3, independent of
MYCN
and
ALK
status, remains to be investigated.
...
PMID:Genes proximal and distal to MYCN are highly expressed in human neuroblastoma as visualized by comparative expressed sequence hybridization. 1816 68
We aimed to directly align a chromosomal CGH (cCGH) pattern with the gene mapping data by taking advantage of the clustering of the GGCC motif at certain positions in the human genome. The alignment of chromosomal with sequence data was achieved by superimposition of (i) the fluorescence intensity of the sequence specific fluorochrome, Chromomycin A3 (CMA3), (ii) the cCGH fluorescence intensity profile of individual chromosomes and (iii) the GGCC density profile extracted from the Ensembl genome sequence database. The superimposition of these three pieces of information allowed us to precisely localize regions of amplification in the neuroblastoma cell line STA-NB-15. Two prominent cCGH peaks were noted, one at 2p24.3, the position 15.4 mega base (Mb), and the other at 2p23.2, 29.51 Mb. FISH and high resolution array CGH (aCGH) experiments disclosed an amplification of
MYCN
(16 Mb) and
ALK
(29.2-29.9 Mb), thus confirming the cCGH data. The combined visualization of sequence information and cCGH data drastically improves the resolution of the method to less than 2 Mb.
...
PMID:Sequence based high resolution chromosomal CGH. 1854 18
Neuroblastoma in advanced stages is one of the most intractable paediatric cancers, even with recent therapeutic advances. Neuroblastoma harbours a variety of genetic changes, including a high frequency of
MYCN
amplification, loss of heterozygosity at 1p36 and 11q, and gain of genetic material from 17q, all of which have been implicated in the pathogenesis of neuroblastoma. However, the scarcity of reliable molecular targets has hampered the development of effective therapeutic agents targeting neuroblastoma. Here we show that the
anaplastic lymphoma kinase
(
ALK
), originally identified as a fusion kinase in a subtype of non-Hodgkin's lymphoma (NPM-
ALK
) and more recently in adenocarcinoma of lung (EML4-
ALK
), is also a frequent target of genetic alteration in advanced neuroblastoma. According to our genome-wide scans of genetic lesions in 215 primary neuroblastoma samples using high-density single-nucleotide polymorphism genotyping microarrays, the
ALK
locus, centromeric to the
MYCN
locus, was identified as a recurrent target of copy number gain and gene amplification. Furthermore, DNA sequencing of
ALK
revealed eight novel missense mutations in 13 out of 215 (6.1%) fresh tumours and 8 out of 24 (33%) neuroblastoma-derived cell lines. All but one mutation in the primary samples (12 out of 13) were found in stages 3-4 of the disease and were harboured in the kinase domain. The mutated kinases were autophosphorylated and displayed increased kinase activity compared with the wild-type kinase. They were able to transform NIH3T3 fibroblasts as shown by their colony formation ability in soft agar and their capacity to form tumours in nude mice. Furthermore, we demonstrate that downregulation of
ALK
through RNA interference suppresses proliferation of neuroblastoma cells harbouring mutated
ALK
. We anticipate that our findings will provide new insights into the pathogenesis of advanced neuroblastoma and that
ALK
-specific kinase inhibitors might improve its clinical outcome.
...
PMID:Oncogenic mutations of ALK kinase in neuroblastoma. 1892 3
Neuroblastoma is the third-most-common solid tumor of childhood. To date, no reliable blood marker for neuroblastoma has been established. The growth factor midkine is highly expressed in human carcinomas and its knockdown leads to tumor growth suppression in animal models. The present study evaluated the plasma midkine level in human neuroblastoma patients. Plasma samples were obtained from patients found through mass screening, as well as from sporadic neuroblastoma patients. The total number of cases examined was 756. Among them, prognostic information was available for 175 sporadic cases and 287 mass-screening cases. Midkine levels were significantly higher in neuroblastoma patients, including both mass-screening cases and sporadic cases, than in non-tumor controls (P < 0.0001). The midkine level was significantly correlated with the statuses of
MYCN
amplification,
TRKA
expression, ploidy, stage and age (P < 0.0001, < 0.0001, = 0.004, < 0.0001 and < 0.0001, respectively), which are known prognostic factors for neuroblastoma. There was a striking correlation between high plasma midkine level and poor prognosis (P < 0.0001). Within sporadic cases, the midkine level was also strikingly higher than in non-tumor controls (P < 0.0001), and correlated with the statuses of
MYCN
amplification and stage (P = 0.0005 and = 0.003, respectively). There was a significant correlation between high plasma midkine level and poor prognosis (P = 0.04). Taken together, the present data indicate that plasma midkine level is a prognostic factor for human neuroblastoma.
...
PMID:Plasma midkine level is a prognostic factor for human neuroblastoma. 1901 68
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