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)

Oncogenic rearrangements of the NTRK1 gene (also designated TRKA), encoding one of the receptors for the nerve growth factor, are frequently detected in thyroid carcinomas. Such rearrangements fuse the NTRK1 tyrosine kinase domain to 5'-end sequences belonging to different genes. In previously reported studies we have demonstrated that NTRK1 oncogenic activation involves two genes, TPM3 and TPR, both localized similarly to the receptor tyrosine kinase, on the q arm of chromosome 1. Here we report the characterization of a novel NTRK1-derived thyroid oncogene, named TRK-T3. A cDNA clone, capable of transforming activity, was isolated from a transformant cell line. Sequence analysis revealed that TRK-T3 contains 1,412 nucleotides of NTRK1 preceded by 598 nucleotides belonging to a novel gene that we have named TFG (TRK-fused gene). The TRK-T3 amino acid sequence displays, within the TFG region, a coiled-coil motif that could endow the oncoprotein with the capability to form complexes. The TRK-T3 oncogene encodes a 68-kDa cytoplasmic protein reacting with NTRK1-specific antibodies. By sedimentation gradient experiments the TRK-T3 oncoprotein was shown to form, in vivo, multimeric complexes, most likely trimers or tetramers. The TFG gene is ubiquitously expressed and is located on chromosome 3. The breakpoint producing the TRK-T3 oncogene occurs within exons of both the TFG gene and the NTRK1 gene and produces a chimeric exon that undergoes alternative splicing. Molecular analysis of the NTRK1 rearranged fragments indicated that the chromosomal rearrangement is reciprocal and balanced and involves loss of a few nucleotides of germ line sequences.
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PMID:The DNA rearrangement that generates the TRK-T3 oncogene involves a novel gene on chromosome 3 whose product has a potential coiled-coil domain. 756 64

Papillary thyroid carcinomas have frequently been found to display oncogenic rearrangements of the NTRK1 gene, which encodes the high-affinity nerve growth factor receptor. Replacement of its extracellular domain by sequences coding for the 221 amino-terminal residues of the TPM3 gene was responsible for the oncogenic NTRK1 activation in three of eight of these tumors. In all of them, the illegitimate recombination involved the 611-bp NTRK1 intron placed upstream of the transmembrane domain and the TPM3 intron located between exons 7 and 8. Therefore, due to the splicing mechanism, all of the TPM3/NTRK1 gene fusions encoded an invariable transcript and the same chimeric protein of 70 kDa, which was constitutively phosphorylated on tyrosine. In two of the three tumors the simultaneous presence of the reciprocal products of the TPM3/NTRK1 recombination, 5'TPM3-3'NTRK1 and 5'NTRK1-3'TPM3 sequences, respectively, and the previously demonstrated localization of both genes on the long arm of chromosome 1 lead us to suggest that an intrachromosomal inversion could be responsible for their recombination. In an attempt to understand the molecular basis that predisposes NTRK1 and TPM3 genes to be a recurrent target of illegitimate recombination, we have determined the nucleotide sequence around the breakpoints of the recombination products in all three patients as well as those of the corresponding regions from the normal TPM3 and NTRK1 genes. In these regions, a search for common features usually involved in illegitimate recombination in mammalian cells revealed the presence of some recombinogenic elements as well as pal-indromes, direct and inverted repeats, and Alu family sequences.
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PMID:A sequence analysis of the genomic regions involved in the rearrangements between TPM3 and NTRK1 genes producing TRK oncogenes in papillary thyroid carcinomas. 759 Jul 42

The prevalence of NTRK1 re-arrangement was determined in papillary thyroid carcinomas (PTCs) of children from Belarus who had been exposed to radioactive iodine after the Chernobyl reactor accident; 81 tumors were included, all of which were devoid of RET re-arrangement as analyzed in a current study on genomic alterations in PTC. Oncogenic fusion of the NTRK1 tyrosine kinase domain with the amino-terminal part of the tropomyosin gene (TPM3/NTRK1, trk) was observed in 5 tumors. A single tumor exhibited a TPR/NTRK1 fusion (TRK-T2). Reciprocal NTRK1/TPM3 transcripts were found in 4 of 5 tumors with TPM3/NTRK1 re-arrangement, indicating an intra-chromosomal balanced reciprocal inversion. No phenotypic differences from other post-Chernobyl childhood PTCs were detected. As compared with the high prevalence of RET re-arrangements reported for thyroid carcinomas of children after the Chernobyl reactor accident, NTRK1 re-arrangements appear rare. Our results confirm that activation of receptor tyrosine kinase genes plays the predominant role in post-Chernobyl childhood thyroid carcinogenesis.
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PMID:NTRK1 re-arrangement in papillary thyroid carcinomas of children after the Chernobyl reactor accident. 1007 15

Anaplastic large cell lymphomas (ALCL) are frequently associated with the t(2;5)(p23;q35). This translocation fuses the nucleophosmin (NPM) gene at 5q35, which encodes a nucleolar protein involved in shuttling ribonucleoproteins from the cytoplasm to the nucleus, to the anaplastic lymphoma kinase (ALK) gene at 2p23, encoding a tyrosine kinase receptor. In this report, we describe a typical case of ALCL whose malignant cells exhibited a novel (1;2)(q25;p23) translocation. These cells expressed ALK protein, but, in contrast to t(2;5)-positive ALCL (which show cytoplasmic, nuclear, and nucleolar staining), labeling was restricted to the malignant cell cytoplasm. Using a polymerase chain reaction (PCR)-based technique to walk on chromosome 2 from the known ALK gene across the breakpoint, we showed that the gene involved at 1q25 is TPM3, encoding a nonmuscular tropomyosin. We subsequently identified, using reverse transcription-PCR analysis of cases showing similar ALK cytoplasm-restricted staining, fusion of the ALK and TPM3 genes in 2 other cases of ALCL. The TPM3 gene has been previously found in papillary thyroid carcinomas as a fusion partner with the TRK kinase gene. We showed that TPM3 is constitutively expressed in lymphoid cell lines, suggesting that, in these t(1;2)-bearing ALCL cases, the TPM3 gene contributes an active promoter for ALK expression. Activation of the ALK catalytic domain probably results from homodimerization of the hybrid protein TPM3-ALK, through the TPM3 protein-protein interaction domain. The present cases of ALCL associated with a novel t(1;2)(q25;p23) demonstrate that at least one fusion partner other than NPM can activate the intracytoplasmic domain of the ALK kinase.
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PMID:A new fusion gene TPM3-ALK in anaplastic large cell lymphoma created by a (1;2)(q25;p23) translocation. 1021 6

Rearrangements of NTRK1 proto-oncogene were detected in 'spontaneous' papillary thyroid carcinomas with a frequency varying from 5 to 25% in different studies. These rearrangements result in the formation of chimaeric genes composed of the tyrosine kinase domain of NTRK1 fused to 5' sequences of different genes. To investigate if the NTRK1 gene plays a role in radiation-induced thyroid carcinogenesis, we looked for the presence of NTRK1-activating rearrangements in 32 human thyroid tumours (16 follicular adenomas, 14 papillary carcinomas and two lymph-node metastases of papillary thyroid carcinomas) from patients who had received external radiation, using the reverse transcription polymerase chain reaction, Southern blot and direct sequencing techniques. These data were compared with those obtained in a series of 28 'spontaneous' benign and malignant thyroid tumours, collected from patients without a history of radiation exposure and four in vitro culture cell lines derived from 'spontaneous' thyroid cancers. Our results concerning the radiation-associated tumours showed that only rearrangements between NTRK1 and TPM3 genes (TRK oncogene) were detected in 2/14 papillary carcinomas and in one lymph-node metastasis of one of these papillary thyroid carcinomas. All the radiation-associated adenomas were negative. In the 'spontaneous' tumours, only one of the 14 papillary carcinomas and one of the four in vitro culture cell lines, derived from a papillary carcinoma, presented a NTRK1 rearrangement also with the TPM3 gene. Twenty-five of this series of radiation-associated tumours were previously studied for the ras and RET/PTC oncogenes. In conclusion, our data: (a) show that the overall frequency of NTRK1 rearrangements is similar between radiation-associated (2/31: 6%) and 'spontaneous' epithelial thyroid tumours (2/32: 6%). The frequency, if we consider exclusively the papillary carcinomas, is in both cases 12%; (b) show that the TRK oncogene plays a role in the development of a minority of radiation-associated papillary thyroid carcinomas but not in adenomas; and (c) confirm that RET/PTC rearrangements are the major genetic alteration associated with ionizing radiation-induced thyroid tumorigenesis.
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PMID:Search for NTRK1 proto-oncogene rearrangements in human thyroid tumours originated after therapeutic radiation. 1064 82

The subset of CD30-positive anaplastic large cell lymphomas (ALCL) with the NPM-ALK gene fusion arising from the t(2;5)(p23;q35) forms a distinct clinical and prognostic entity. Recently, various cytogenetic, molecular, and protein studies have provided evidence for the existence of several types of variant ALK fusions in up to 20% of ALK+ ALCL, of which only one, a TPM3-ALK fusion resulting from a t(1;2)(q25;p23), has so far been cloned. A cryptic inv(2)(p23q35) has been described as another recurrent cytogenetic alteration involving ALK and an unidentified fusion partner in some ALCL. In a screen for variant ALK gene fusions, we identified two ALCL that were negative for NPM-ALK by reverse transcriptase-polymerase chain reaction, but were positive for cytoplasmic ALK with both polyclonal and monoclonal antibodies to the ALK tyrosine kinase domain, consistent with ALK deregulation by an alteration other than the t(2;5) Case 1 was a T-lineage nodal and cutaneous ALCL in a 52-year-old woman, and Case 2 was a T-lineage nodal ALCL in a 12-year-old girl. FISH analysis confirmed ALK rearrangement in both cases. An inverse polymerase chain reaction approach was then used to identify the ALK translocation partner in Case 1. We found an in-frame fusion of ALK to ATIC, a gene previously mapped to 2q34-q35. We then confirmed by DNA polymerase chain reaction the localization of ATIC to yeast artificial chromosome (YAC) 914E7 previously reported to span the 2q35 break in the inv(2)(p23q35). FISH analysis in Case 1 confirmed rearrangement of YAC 914E7 and fusion to ALK. The ATIC-ALK fusion was confirmed in Case 1 and also identified in Case 2 by conventional reverse transcriptase-polymerase chain reaction using ATIC forward and ALK reverse primers. ATIC encodes an enzyme involved in purine biosynthesis which, like other fusion partners of ALK, is constitutively expressed and appears to contain a dimerization domain. ATIC-ALK fusion resulting from the inv(2)(p23q35) thus provides a third mechanism of ALK activation in ALK+ ALCL.
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PMID:ATIC-ALK: A novel variant ALK gene fusion in anaplastic large cell lymphoma resulting from the recurrent cryptic chromosomal inversion, inv(2)(p23q35). 1070 93

Inflammatory myofibroblastic tumors (IMTs) are neoplastic mesenchymal proliferations featuring an inflammatory infiltrate composed primarily of lymphocytes and plasma cells. The myofibroblastic cells in some IMTs contain chromosomal rearrangements involving the ALK receptor tyrosine-kinase locus region (chromosome band 2p23). ALK-which is normally restricted in its expression to neural tissues-is expressed strikingly in the IMT cells with 2p23 rearrangements. We now report a recurrent oncogenic mechanism, in IMTs, in which tropomyosin (TPM) N-terminal coiled-coil domains are fused to the ALK C-terminal kinase domain. We have cloned two ALK fusion genes, TPM4-ALK and TPM3-ALK, which encode approximately 95-kd fusion oncoproteins characterized by constitutive kinase activity and tyrosylphosphorylation. Immunohistochemical and molecular correlations, in other IMTs, implicate non-TPM ALK oncoproteins that are predominantly cytoplasmic or pre- dominantly nuclear, presumably depending on the subcellular localization of the ALK fusion partner. Notably, a TPM3-ALK oncogene was reported recently in anaplastic lymphoma, and TPM3-ALK is thereby the first known fusion oncogene that transforms, in vivo, both mesenchymal and lymphoid human cell lineages.
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PMID:TPM3-ALK and TPM4-ALK oncogenes in inflammatory myofibroblastic tumors. 1143 87

Despite its clinical and histological heterogeneity, anaplastic large cell lymphoma (ALCL) is now a well-recognized clinicopathological entity accounting for 2% of all adult non-Hodgkin's lymphomas (NHL) and about 13% of pediatric NHL. Immunophenotypically, ALCL are of T cell (predominantly) or Null cell type; by definition, cases expressing B cell antigens are officially not included in this entity. The translocation (2;5)(p23;q35) is a recurring abnormality in ALCL; 46% of the ALCL patients bear this signature translocation. This translocation creates a fusion gene composed of nucleophosmin (NPM) and a novel receptor tyrosine kinase gene, named anaplastic lymphoma kinase (ALK). The NPM-ALK chimeric gene encodes a constitutively activated tyrosine kinase that has been shown to be a potent oncogene. The exact pathogenetic mechanisms leading to lymphomagenesis remain elusive; however, the synopsis of evidence obtained to date provides an outline of likely scenarios. Several t(2;5) variants have been described; in some instances, the breakpoints have been cloned and the genes forming a new fusion gene with ALK have been identified: ATIC-ALK, TFG-ALK and TPM3-ALK. Cloning the translocation breakpoint and identifying the ALK and NPM genes provided tools for screening material from patients with ALCL using various approaches at the chromosome, DNA, RNA, or protein level: positive signals in the reverse transcriptase-polymerase chain reaction (RT-PCR) and the immunostaining with anti-ALK monoclonal antibodies (McAb) serve as the most convenient tests for detection of the t(2;5) NPM-ALK since the fusion gene and ALK protein expression do not occur in normal or reactive lymphoid tissue. The wide range of NPM-ALK positivity reported in different series appears to be dependent on the inclusion and selection criteria of the ALCL cases studied. Overall, however, 43% of ALCL cases were NPM-ALK+ (83% of pediatric ALCL vs 31% of adult ALCL). Occasional non-ALCL B cell lymphomas (4%) with diffuse large cell and immunoblastic histology and Hodgkin's disease cases (3%) were NPM-ALK-, but these data are questionable. The aggregate results indicate that, in contrast to primary nodal (systemic) ALCL, the t(2;5) may be present in only 10-20% of primary cutaneous ALCL and rarely, if at all, in lymphomatoid papulosis, a potential precursor lesion; however, these 10-20% positive cases were not confirmed by anti-ALK McAb immunostaining and may represent an overestimate. Positivity for NPM-ALK is associated to various degrees with the following parameters: 44% and 45% of ALCL cases with T cell and Null cell immunophenotype, respectively, are positive, whereas only 8% of cases with a B cell immunoprofile are positive; the mean age of positive patients is significantly younger than that of negative patients; positive cases carry a better overall prognosis (but not in all studies). Recently, the homogenous category of ALK lymphoma ('ALKoma') has emerged as a distinct pathological entity within the heterogenous group of ALCL. The fact that patients with ALK lymphomas experience significantly better overall survival than ALK- ALCL demonstrates further that analysis of ALK expression has important prognostic implications. The term ALK lymphoma signifies a switch in the use of the diagnostic criteria: cases are selected on the basis of a genetic abnormality (the ALK rearrangement), instead of the review of morphological or immunophenotypical features which are clearly more prone to disagreement and controversy. Since its initial description in 1985 ALCL has become one of the best characterized lymphoma entities.
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PMID:Pathobiology of NPM-ALK and variant fusion genes in anaplastic large cell lymphoma and other lymphomas. 1099 99

Inflammatory myofibroblastic tumors (IMT) are mesenchymal solid tumors that occur preferentially in children and young adults. They present as myofibroblastic cell proliferations accompanied by plasmocytes and lymphocytes. Recent cytogenetic and molecular observations showed non-random abnormalities of chromosomal band 2p23 resulting in a rearrangement of the ALK gene. This finding of a specific gene alteration suggests a neoplastic rather than a reactive inflammatory process for IMT tumorigenesis. ALK is a tyrosine kinase oncogene initially found to be rearranged in anaplastic large-cell lymphomas (ALCL). Of note, the breakpoints within ALK, and also within some of the ALK fusion gene partners, such as TPM3 or CLTC, are similar in IMT and ALCL. The consistent involvement of ALK, together with the diversity of partner genes, underlines the central role of ALK constitutive activation in IMT development, as well as the importance of homodimerization mechanisms of the chimeric fusion proteins in this activation. Immunohistochemical analyses performed on paraffin embedded tissue sections have shown positive ALK expression with cytoplasmic localization in half of the IMT cases containing the molecular ALK rearrangement. In conclusion, these novel molecular data have defined a group of IMT of neoplastic origin characterized by the presence of ALK alterations. The description of ALK gene rearrangements in IMT and ALCL is the second example, after the observation of ETV6-NTRK3 in congenital fibrosarcoma and in a case of chronic myeloid leukemia, of identical gene fusions occurring in two different cell lines: hematopoietic and mesenchymal. The search for rearrangement of ALK by fluorescence in situ hybridization (FISH) is a useful complementary tool for IMT diagnosis.
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PMID:[Inflammatory myofibroblastic tumors]. 1259 87

Inflammatory myofibroblastic tumor (IMT), synonymously referred to as inflammatory pseudotumor, is a distinctive mesenchymal lesion composed of spindle cells displaying morphological features of myofibroblasts admixed with considerable numbers of inflammatory cells. Recent genetic and molecular studies have shown that a subset of IMT is characterized by the expression of altered anaplastic lymphoma kinase (ALK) protein mostly resulting from rearrangements of the ALK gene such as TPM3-ALK, TPM4-ALK and CLTC-ALK fusion genes. We analyzed the ALK status in nine cases of IMT arising in various anatomical locations. Six cases showed immunohistochemical expression of the ALK protein, and two ALK-positive lesions examined by reverse transcription-polymerase chain reaction and a subsequent sequencing analysis harbored the TPM4-ALK fusion gene. Of note, the majority of ALK-positive tumor cells in four of the six lesions lacked the coexpression of myogenic markers including alpha-smooth muscle actin, a cytoskeletal protein indicating myofibroblastic differentiation, whereas a substantial number of tumor cells in the remaining two cases coexpressed ALK and alpha-smooth muscle actin and/or desmin. In an ultrastructural study of the lesion with predominant ALK-positive/actin-negative cells, spindle cells failed to demonstrate features of myofibroblasts such as intracytoplasmic bundles of thin filaments and dense bodies. The current findings suggest that ALK-positive cells in IMT are not always myofibroblastic but might be immature primitive mesenchymal cells.
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PMID:Inflammatory myofibroblastic tumor with predominant anaplastic lymphoma kinase-positive cells lacking a myofibroblastic phenotype. 1278 12


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