Distribution by Scientific Domains
Distribution within Medical Sciences

Kinds of Kit

  • available kit
  • commercial elisa kit
  • commercial kit
  • detection kit
  • diagnostic kit
  • elisa kit
  • emergency kit
  • enzyme immunoassay kit
  • extraction kit
  • immunoassay kit
  • mesh kit
  • mini kit
  • survival kit
  • test kit
  • tool kit

  • Terms modified by Kit

  • kit exon
  • kit expression
  • kit gene
  • kit ligand
  • kit mutation

  • Selected Abstracts

    Treatment responses to cladribine and dasatinib in rapidly progressing aggressive mastocytosis

    K. J. Aichberger
    ABSTRACT Background, Systemic mastocytosis (SM) is a mast cell neoplasm in which neoplastic cells usually display the D816V-mutated variant of KIT. Cladribine (2CdA) and dasatinib are two drugs that counteract the in vitro growth of neoplastic mast cells in SM. However, only little is known about the in vivo effects of these drugs in SM. Patient and methods, We report on a patient with highly aggressive interferon-alpha-resistant SM who was treated with 2CdA and dasatinib. In vitro pretesting revealed a response of neoplastic mast cells to both compounds with reasonable IC50 values. Results, The patient was treated with six cycles of 2CdA (0·13 mg kg,1 intravenously daily on 5 consecutive days). Despite a short-lived major clinical response and a decrease in serum tryptase, the patient progressed to mast cell leukaemia after the sixth cycle of 2CdA. The patient then received two further courses of 2CdA followed by treatment with dasatinib (100 mg per os daily). However, no major response was obtained and the patient died from disease progression after 2 months. Conclusions, In a patient with rapidly progressing aggressive SM, neither 2CdA nor dasatinib produced a long-lasting response in vivo, despite encouraging in vitro results. For such patients, alternative treatment strategies have to be developed. [source]

    Mixed-lineage eosinophil/basophil crisis in MDS: a rare form of progression

    F. Wimazal
    ABSTRACT Background, Basophilic crisis and eosinophilia are well recognized features of advanced chronic myeloid leukaemia. In other myeloid neoplasms, however, transformation with marked basophilia and eosinophilia is considered unusual. Design, We examined the long-term follow-up of 322 patients with de novo myelodysplastic syndromes (MDS) to define the frequency of basophilic, eosinophilic and mixed lineage (basophilic and eosinophilic) transformation. Results, Of all patients, only one developed mixed lineage crisis (, 20% basophils and , 20% eosinophils). In this patient, who initially suffered from chronic myelomonocytic leukaemia, basophils increased to 48% and eosinophils up to 31% at the time of progression. Mixed lineage crisis was not accompanied by an increase in blast cells or organomegaly. The presence of BCR/ABL and other relevant fusion gene products (FIP1L1/PDGFRA, AML1/ETO, PML/RAR,, CBF,/MYH11) were excluded by PCR. Myelomastocytic transformation/myelomastocytic leukaemia and primary mast cell disease were excluded by histology, KIT mutation analysis, electron microscopy and immunophenotyping. Basophils were thus found to be CD123+, CD203c+, BB1+, KIT- cells, and to express a functional IgE-receptor. Among the other patients with MDS examined, 4(1·2%) were found to have marked basophilia (, 20%) and 7(2·1%) were found to have massive eosinophilia ( , 20%), whereas mixed-lineage crisis was detected in none of them. Conclusions, Mixed basophil/eosinophil crisis may develop in patients with MDS but is an extremely rare event. [source]

    High resolution analysis of follicular lymphoma genomes reveals somatic recurrent sites of copy-neutral loss of heterozygosity and copy number alterations that target single genes,

    K-John J. Cheung
    A multiplatform approach, including conventional cytogenetic techniques, BAC array comparative genomic hybridization, and Affymetrix 500K SNP arrays, was applied to the study of the tumor genomes of 25 follicular lymphoma biopsy samples with paired normal DNA samples to characterize balanced translocations, copy number imbalances, and copy-neutral loss of heterozygosity (cnLOH). In addition to the t(14;18), eight unique balanced translocations were found. Commonly reported FL-associated copy number regions were revealed including losses of 1p32-36, 6q, and 10q, and gains of 1q, 6p, 7, 12, 18, and X. The most frequent regions affected by copy-neutral loss of heterozygosity were 1p36.33 (28%), 6p21.3 (20%), 12q21.2-q24.33 (16%), and 16p13.3 (24%). We also identified by SNP analysis, 45 aberrant regions that each affected one gene, including CDKN2A, CDKN2B, FHIT, KIT, PEX14, and PTPRD, which were associated with canonical pathways involved in tumor development. This study illustrates the power of using complementary high-resolution platforms on paired tumor/normal specimens and computational analysis to provide potential insights into the significance of single-gene somatic aberrations in FL tumorigenesis. © 2010 Wiley-Liss,Inc. [source]

    Hereditary gastrointestinal stromal tumors sharing the KIT Exon 17 germline mutation p.Asp820Tyr develop through different cytogenetic progression pathways

    Isabel Veiga
    Hereditary gastrointestinal stromal tumor (GIST) syndrome is a rare autosomal dominant genetic disorder originated by germline mutations in the KIT or PDGFRA genes. We report the third family with hereditary predisposition to GIST due to the KIT Exon 17 germline mutation p.Asp820Tyr and characterize the cytogenetic progression pathways followed by different GIST sharing the same primary genetic event, using a combination of chromosome banding, comparative genomic hybridization (CGH), and fluorescence in situ hybridization (FISH) analyses. The missense mutation p.Asp820Tyr was detected in the proband's rectal and gastric GIST, as well as in his aunt's GIST epiplon metastasis. The mutation p.Asp820Tyr was subsequently also found in the proband's peripheral blood DNA, as well as in that of 4 of 10 relatives thus far analyzed. CGH analysis revealed loss of 14q and 15q in the proband's gastric lesion, whereas FISH analysis of the proband's rectal GIST did not detect loss of 14q and 15q, but instead loss of 4q and 22q and gain of 20q, indicating that the two tumors were independent GIST. Chromosome banding and CGH analyses of the aunt's GIST epiplon metastasis revealed multiple cytogenetic alterations, including 1p loss, but none in common with the two proband's GIST. We conclude that, although the patients share the same KIT Exon 17 germline mutation, the multiple GIST analyzed followed different pathogenetic progression pathways, each of which did not significantly differ from what has been described in sporadic GIST. © 2009 Wiley-Liss, Inc. [source]

    Genes, chromosomes and the development of testicular germ cell tumors of adolescents and adults

    Alan McIntyre
    Testicular germ cell tumors (TGCTs) of adults and adolescents are thought to be derived from primordial germ cells or gonocytes. TGCTs develop postpuberty from precursor lesions known as intratubular germ cell neoplasia undifferentiated. The tumors can be divided into two groups based on their histology and clinical behavior; seminomas resemble primordial germ cells or gonocytes and nonseminomas resemble embryonic or extraembryonic tissues at various stages of differentiation. The most undifferentiated form of nonseminoma, embryonal carcinoma, resembles embryonic stem cells in terms of morphology and expression profiling, both mRNAs and microRNAs. Evidence supports both environmental factors and genetic predisposition underlying the development of TGCTs. Various models of development have been proposed and are discussed. In TGCTs, gain of material from the short arm of chromosome 12 is invariable: genes from this region include the proto-oncogene KRAS, which has activating mutations in ,10% of tumors or is frequently overexpressed. A number of different approaches to increase the understanding of the development and progression of TGCTs have highlighted the involvement of KIT, RAS/RAF/MAPK, STAT, and PI3K/AKT signaling. We review the role of these signaling pathways in this process and the potential influence of environmental factors in the development of TGCTs. © 2008 Wiley-Liss, Inc. [source]

    Further characterization of the first seminoma cell line TCam-2

    Jeroen de Jong
    Testicular germ cell tumors of adolescents and adults (TGCTs) can be classified into seminomatous and nonseminomatous tumors. Various nonseminomatous cell lines, predominantly embryonal carcinoma, have been established and proven to be valuable for pathobiological and clinical studies. So far, no cell lines have been derived from seminoma which constitutes more than 50% of invasive TGCTs. Such a cell line is essential for experimental investigation of biological characteristics of the cell of origin of TGCTs, i.e., carcinoma in situ of the testis, which shows characteristics of a seminoma cell. Before a cell line can be used as model, it must be verified regarding its origin and characteristics. Therefore, a multidisciplinary approach was undertaken on TCam-2 cells, supposedly the first seminoma cell line. Fluorescence in situ hybridization, array comparative genomic hybridization, and spectral karyotyping demonstrated an aneuploid DNA content, with gain of 12p, characteristic for TGCTs. Genome wide mRNA and microRNA expression profiling supported the seminoma origin, in line with the biallelic expression of imprinted genes IGF2/H19 and associated demethylation of the imprinting control region. Moreover, the presence of specific markers, demonstrated by immunohistochemistry, including (wild type) KIT, stem cell factor, placental alkaline phosphatase, OCT3/4 (also demonstrated by a specific Q-PCR) and NANOG, and the absence of CD30, SSX2-4, and SOX2, confirms that TCam-2 is a seminoma cell line. Although mutations in oncogenes and tumor suppressor genes are rather rare in TGCTs, TCam-2 had a mutated BRAF gene (V600E), which likely explains the fact that these cells could be propagated in vitro. In conclusion, TCam-2 is the first well-characterized seminoma-derived cell line, with an exceptional mutation, rarely found in TGCTs. © 2007 Wiley-Liss, Inc. [source]

    Expression and mutational analyses of KIT and PDGFR-, in sarcomatoid renal cell carcinoma

    HISTOPATHOLOGY, Issue 2 2009
    Anna Petit
    No abstract is available for this article. [source]

    Clinical significance of oncogenic KIT and PDGFRA mutations in gastrointestinal stromal tumours

    HISTOPATHOLOGY, Issue 3 2008
    J Lasota
    Gastrointestinal stromal tumours (GISTs) are the most common mesenchymal neoplasms of the gastrointestinal tract. Despite clinicopathological differences, GISTs share oncogenic KIT or platelet-derived growth factor-alpha (PDGFRA) mutations. Imatinib, KIT and PDGFRA inhibitor, has been successfully used in the treatment of metastatic GISTs. There are primary KIT or PDGFRA mutations diagnosed before imatinib treatment, linked to GIST pathogenesis, and secondary mutations detected during treatment, causing drug resistance. KIT exon 11 mutations are the most common. Gastric GISTs with exon 11 deletions are more aggressive than those with substitutions. KIT exon 11 mutants respond well to imatinib. Less common KIT exon 9 Ala502_Tyr503dup mutants occur predominantly in intestinal GISTs and are less sensitive to imatinib. An Asp842Val substitution in exon 18 is the most common PDGFRA mutation. GISTs with such mutation are resistant to imatinib. PDGFRA mutations are associated with gastric GISTs, epithelioid morphology and a less malignant course of disease. GISTs in neurofibromatosis 1, Carney triad and paediatric tumours generally lack KIT and PDGFRA mutations. Secondary KIT mutations affect exons 13,17. GISTs with secondary mutations in exon 13 and 14 are sensitive to sunitinib, another tyrosine kinase inhibitor. KIT and PDGFRA genotyping is important for GIST diagnosis and assessment of sensitivity to tyrosine kinase inhibitors. [source]

    KIT and RAS signalling pathways in testicular germ cell tumours: new data and a review of the literature

    N. C. Goddard
    Summary Testicular germ cell tumours (TGCTs) are the leading cause of cancer deaths in young male Caucasians. Identifying changes in DNA copy number can pinpoint genes involved in tumour development. We defined the smallest overlapping regions of imbalance in TGCTs using array comparative genomic hybridization analysis. Novel regions, or regions which refined those previously reported, were identified. The expression profile of genes from 12p, which is invariably gained in TGCTs, and amplicons defined at 12p11.2-12.1 and 4q12, suggest KRAS and KIT involvement in TGCT and seminoma development, respectively. Amplification of these genes was not found in intratubular germ cell neoplasia adjacent to invasive disease showing these changes, suggesting their involvement in tumour progression. Activating mutations of RAS genes (KRAS or NRAS) and overexpression of KRAS were mutually exclusive events. These, correlations between the expression levels of KIT, KRAS and GRB7 (which encodes an adapter molecule known to interact with the KIT tyrosine kinase receptor) and other reported evidence reviewed here, are consistent with a role for activation of KIT and RAS signalling in TGCT development. In order to assess a role for KIT in seminomas, we modulated the level of KIT expression in TCam-2, a seminoma cell line. The likely seminomatous origin of this cell line was supported by demonstrating KIT and OCT3/4 overexpression and gain of 12p material. Reducing the expression of KIT in TCam-2 through RNA inhibition resulted in decreased cell viability. Further understanding of KIT and RAS signalling in TGCTs may lead to novel therapeutic approaches for these tumours. [source]

    Strong expression of IGF1R in pediatric gastrointestinal stromal tumors without IGF1R genomic amplification,

    Katherine A. Janeway
    Abstract Wildtype (WT) gastrointestinal stromal tumors (GISTs), lacking mutations in KIT or PDGFRA, represent 85% of GISTs in pediatric patients. Treatment options for pediatric WT GIST are limited. Recently, expression profiling of a limited number of pediatric and adult WT GISTs and more in depth study of a single pediatric WT GIST implicated the insulin-like growth factor 1 receptor (IGF1R) as a potential therapeutic target in pediatric WT GIST. We performed immunoblotting, SNP and FISH studies to determine the extent of expression, biochemical activation and genomic amplification of IGF1R in a larger number of pediatric WT GISTs. Pediatric WT GISTs expressed IGF1R strongly, whereas typical adult KIT mutant GISTs did not. IGF1R gene amplification was not detected in pediatric WT GISTs, and some KIT -mutant GISTs had IGF1R gene deletion due to monosomy 15. Despite the absence of apparent genomic activation mechanisms accounting for overexpression, clinical study of IGF1R-directed therapies in pediatric WT GIST is warranted. [source]

    Genetic mapping of dominant white (W), a homozygous lethal condition in the horse (Equus caballus)

    C. Mau
    Summary Dominant white coat colour (W) is a depigmentation syndrome, known in miscellaneous species. When homozygous in the horse (similar in mice), the mutation responsible for the white phenotype is lethal in a very early stage of gestation. It seems, that the action of the dominant white allele is not always fully penetrant, resulting occasionally in spotted look alike offspring. These horses resemble a coat colour pattern known as sabino spotting. So far, it is not known whether dominant white (W) and sabino spotting (S) share a common genetic background. In this study, a pedigree consisting of 87 horses segregating for dominant white (W) was used to genetically localize the horse (W)-locus. Microsatellite ASB23 was found linked to (W), which allowed us to map dominant white to a region on horse chromosome 3q22. Tyrosine kinase receptor (KIT) was previously mapped to this same chromosome region (3q21,22). KIT and its ligand (KITLG) are responsible for the normal function of melanogenesis, haematopoiesis and gametogenesis. So far, sequence analysis of different KIT gene fragments did not lead to new polymorphisms, except for a SNP detected in KIT intron 3 (KITSNPIn3). Additional microsatellites from ECA3q (TKY353 and LEX7), together with KITSNPIn3 allowed us to state more precisely the (W)-mutation. The positional results and comparative functional data strongly suggest that KIT encodes for the horse (W)-locus. Zusammenfassung Die dominant weisse Fellfarbe (W) ist eine Form der Depigmentierung, die bei vielen Spezies auftritt. Beim Pferd wirkt die Mutation für Dominant Weiss (W) in homozygoter Form (analog zur Maus), bereits in einem sehr frühen Stadium der Trächtigkeit letal. Es scheint, dass die Wirkung des dominant weissen Allels nicht immer mit vollständiger Penetranz erfolgt. Dies führt gelegentlich zu Nachkommen mit einer Art Schecken-Fellzeichnung. Solche Pferde sind phänotypisch mit den sogenannten ,,Sabino-Schecken,, vergleichbar. Es ist bis jetzt nicht bekannt ob Dominant Weiss (W) und Sabino-Scheckung (S) einen gemeinsamen genetischen Hintergrund besitzen. Mittels eines Pedigrees aus 87 Pferden, in dem Dominant Weiss (W) segregiert, konnte in der vorliegenden Studie der equine (W)-Locus genetisch lokalisiert werden. Der Mikrosatellit ASB23 erwies sich als gekoppelt mit (W) und ermöglichte die Zuweisung des (W)-Locus auf eine Region von Chromosom ECA 3q22. Das Gen für den Tyrosinkinaserezeptor (KIT) liegt ebenfalls in dieser Chromosomenregion (3q21,22). Das KIT -Gen ist zusammen mit dem KIT -Liganden (KITLG) verantwortlich für einen normal funktionierenden Ablauf der Melanogenese, Hämatopoese und Gametogenese. Die direkte Sequenzierung von KIT -Genfragmenten führte bis jetzt zu keinen neuen Polymorphismen, ausser einem SNP in KIT Intron 3 (KITSNPIn3). Mittels weiterer Mikrosatelliten von ECA3q (TKY353 and LEX7) sowie KITSNPIn3 gelang es, die (W)-Mutation genauer zu positionieren. Die vorliegenden Lokalisierungsresultate und vergleichende funktionelle Erkenntnisse deuten stark darauf hin, dass KIT für den Pferde (W)-Locus kodiert. [source]

    Deficiency of KIT-positive cells in the colon of patients with diabetes mellitus

    Abstract Background Diabetes mellitus is a well-known cause of gastrointestinal dysmotility. The pathogenesis of diabetic gastroenteropathy is mainly considered to be a neuropathy, but the cause of dysmotility remains unknown. Interstitial cells of Cajal (ICC), which express c-kit receptor tyrosine kinase (KIT), are considered to be pacemaker cells for the gastrointestinal movement. Therefore, we investigated a possible involvement of ICC in the pathogenesis of diabetic gastroenteropathy in humans. Methods The KIT-positive cells in the proper muscle layer of the colon were detected by immunohistochemistry in patients with diabetes mellitus and normal control subjects. Mast cells, which are also known to express KIT, were detected by staining with Alcian blue. The numbers of KIT-positive cells and Alcian blue-positive cells in the proper muscle layer were counted under the microscope and the number of KIT-positive cells apart from Alcian blue-positive cells was calculated. Results In the normal control subjects, KIT-positive cells were located at the myenteric plexus region and in the circular muscle layer of the colon. Their distribution pattern was similar to that of ICC. The average number of KIT-positive cells, apart from mast cells (which reflects the number of ICC), in patients with diabetes mellitus was approximately 40% of that found in normal subjects. Conclusions Deficiency of ICC might be related to the pathogenesis of diabetic gastroenteropathy in humans. [source]

    Advances in the diagnosis and management of cutaneous mast cell tumours in dogs

    J. M. Dobson
    Mast cell tumours are one of the most common tumours of the canine skin and have a reputation for being difficult to manage because of their variable clinical presentation, behaviour and response to treatment. This review of recent literature on canine mast cell tumours suggests that the majority of such tumours may not be as bad as their reputation suggests. Most grade I and grade II tumours can be managed successfully by good surgery. Recent literature also calls into question the utility of clinical staging systems and the value of assessing surgical margins for prognosis and highlights the paucity of well-conducted, case-controlled clinical trials in assessing the efficacy of medical management of high-risk tumours. In terms of more basic research, recent studies have implicated the stem cell factor receptor KIT as having a role in the aetiology of canine mast cell tumours and there appears to be an association between c-kit mutation and higher grade of tumour. This may offer a possible target for new therapeutic approaches. [source]

    Identification of tryptase- and chymase-related gene clusters in human mast cells using microarrays

    ALLERGY, Issue 3 2006
    C. Dahl
    Tryptase and chymase are the two major granular proteases present in human mast cell (MC)s. We used oligonucleotide microarray to measure the levels of approximately 22 000 transcripts in cord blood-derived MCs at 4 weeks, 8 weeks, 12 weeks and 18 weeks in culture. Tryptase (TPSB2) was expressed at the highest level among all transcripts and its expression level reached a plateau at 8 weeks. On the other hand, the expression level of chymase (CMAI) doubled every 4,6 weeks. A similar tendency was found at the protein levels with FACS analysis. After filtering the transcripts with MC-specificity, hierarchical clustering analysis identified 494 and 81 transcripts in the same clusters with tryptase and chymase, respectively. MC-specific genes, KIT and HDC were found in the tryptase cluster. In the chymase cluster, a critical suppressor for cell senescence, BMI1 and the several related genes were found, suggesting that chymase expression may be closely related to cell senescence/quiescence events. [source]

    Immunohistochemical analysis of receptor tyrosine kinase signal transduction activity in chordoma

    J. H. Fasig
    Aims: Currently, there are no effective chemotherapeutic protocols for chordoma. Reports of receptor tyrosine kinase (RTK) expression in chordoma suggest that these tumours may respond to kinase inhibitor therapy. However, RTK signalling activity has not been extensively investigated in chordoma. Methods: A tissue microarray containing 21 cases of chordoma was analysed for expression of a number of proteins involved in signal transduction from RTKs by immunohistochemistry. Results: Platelet-derived growth factor receptor-,, epidermal growth factor receptor (EGFR), KIT and HER2 were detected in 100%, 67%, 33% and 0% of cases, respectively. Platelet-derived growth factor receptor-, staining was of moderate-to-strong intensity in 20 of 21 cases. In contrast, KIT immunoreactivity was weak and focal in each of the seven positive cases. Total EGFR staining was variable; weak staining for phosphorylated EGFR was detected in nine cases. Phosphorylated isoforms of p44/42 mitogen-activated protein kinase, Akt and STAT3, indicative of tyrosine kinase activity, were detected in 86%, 76% and 67% of cases, respectively. Conclusions: Chordomas commonly express RTKs and activated signal transduction molecules. Although there were no statistically significant correlations between the expression of any of the markers studied and disease-free survival or tumour location, the results nonetheless indicate that chordomas may respond to RTK inhibitors or modulators of other downstream signalling molecules. [source]

    Pathology of gastrointestinal stromal tumors

    Seiichi Hirota
    Gastrointestinal stromal tumors (GIST) are the most common mesenchymal tumors in the gastrointestinal tract. It was found that most GIST expressed KIT, a receptor tyrosine kinase encoded by protooncogene c- kit. In normal gastrointestinal wall, KIT is expressed by interstitial cells of Cajal (ICC), which are a pacemaker for autonomous gastrointestinal movement. Because both GIST and ICC are double-positive for KIT and CD34, and because familial and multiple GIST appear to develop from diffuse hyperplasia of ICC, GIST are considered to originate from ICC or their precursor cells. It was also found that approximately 90% of the sporadic GIST have somatic gain-of-function mutations of the c- kit gene, and that the patients with familial and multiple GIST have germline gain-of-function mutations of the c- kit gene. These facts strongly suggest that the c- kit gene mutations are a cause of GIST. Approximately half of the sporadic GIST without c- kit gene mutations were demonstrated to have gain-of-function mutations in platelet-derived growth factor receptor-, (PDGFRA) gene that encodes another receptor tyrosine kinase. Because KIT is immunohistochemically negative in a minority of GIST, especially in PDGFRA gene mutation-harboring GIST, mutational analyses of c- kit and PDGFRA genes may be required to diagnose such GIST definitely. Imatinib mesylate was developed as a selective tyrosine kinase inhibitor. It inhibits constitutive activation of mutated KIT and PDGFRA, and is now being used for KIT-positive metastatic or unresectable GIST as a molecular target drug. Confirmation of KIT expression by immunohistochemistry is necessary for application of the drug. The effect of imatinib mesylate is different in various types of c- kit and PDGFRA gene mutations, and the secondary resistance against imatinib mesylate is often acquired by the second mutation of the identical genes. Mutational analyses of c- kit and PDGFRA genes are also significant for prediction of effectiveness of drugs including newly developed agents. [source]

    PKC theta, a novel immunohistochemical marker for gastrointestinal stromal tumors (GIST), especially useful for identifying KIT-negative tumors

    Atsushi Motegi
    Gastrointestinal stromal tumor (GIST) is the most common mesenchymal tumor in the digestive tract and the majority of GIST has characteristic gain-of-function mutations of the c-kit gene, which encodes the KIT receptor for stem cell factor. The present study aimed to establish the usefulness of protein kinase C theta (PKC ,) as an immunohistochemical marker for GIST in comparison with KIT immunohistochemistry. PKC , immunohistochemistry was carried out not only on 48 cases of GIST and another 40 cases of gastrointestinal mesenchymal tumors, but also on 24 cases of various tumors known to be immunohistochemically positive for KIT. Immunohistochemically, 41 out of 48 cases (85%) of GIST were positive for PKC ,, and its expression was confirmed by Western blot analysis using six cases of surgically resected GIST. In the present study there were six GIST immunohistochemically negative for KIT, which histologically revealed a myxoid epithelioid appearance characteristic to that of GIST with platelet-derived growth factor receptor alpha mutation. All six GIST were immunohistochemically positive for PKC ,. No PKC , immunoreactivity was observed in other gastrointestinal mesenchymal tumors and various KIT-positive tumors except for three cases (14%) of gastrointestinal schwannomas. The present study revealed that PKC , is an immunohistochemically novel and useful marker for GIST, especially for GIST negative for KIT. [source]

    Establishment and characterization of a KIT-positive and stem cell factor-producing cell line, KTHOS, derived from human osteosarcoma

    Toshiaki Hitora
    Osteosarcoma is a malignant bone tumor that commonly affects adolescents and young adults. In the present study a human osteosarcoma cell line, KTHOS, was established from a primary osteosarcoma lesion in the distal femur of a 16-year-old girl. After 106 passages, the KTHOS cell line retained the biological characteristics of osteosarcoma. The KTHOS cells had spindle to pleomorphic cytoplasm with round to ovoid nuclei containing multiple prominent nucleoli, as expected based on the mesodermic origin of osteoblasts. The KTHOS cells were immunoreactive for osteocalcin, osteonectin, stem cell factor (SCF), and KIT (CD117). Reverse transcriptase,polymerase chain reaction indicated that the KTHOS cell line expressed mRNA for SCF and KIT. The KTHOS cells produced relatively high amounts of soluble SCF as determined by enzyme-linked immunosorbent assay. The results suggest that cell proliferation of the KTHOS cell line might be involved in autocrine and/or paracrine loops of the SCF/KIT signaling system. The KTHOS cell line is a novel human osteosarcoma cell line that releases SCF and expresses KIT. This cell line can be used for studies to explore the mechanisms for oncogenesis of human osteosarcomas. [source]

    Barrier requirements as the evolutionary "driver" of epidermal pigmentation in humans

    Peter M. Elias
    Current explanations for the development of epidermal pigmentation during human evolution are not tenable as stand-alone hypotheses. Accordingly, we assessed instead whether xeric- and UV-B-induced stress to the epidermal permeability barrier, critical to survival in a terrestrial environment, could have "driven" the development of epidermal pigmentation. (1) Megadroughts prevailed in central Africa when hominids expanded into open savannahs [,1.5,0.8 million years ago], resulting in sustained exposure to both extreme aridity and erythemogenic UV-B, correlating with genetic evidence that pigment developed ,1.2 million years ago. (2) Pigmented skin is endowed with enhanced permeability barrier function, stratum corneum integrity/cohesion, and a reduced susceptibility to infections. The enhanced function of pigmented skin can be attributed to the lower pH of the outer epidermis, likely due to the persistence of (more-acidic) melanosomes into the outer epidermis, as well as the conservation of genes associated with eumelanin synthesis and melanosome acidification (e.g., TYR, OCA2 [p protein], SLC24A5, SLC45A2, MATP) in pigmented populations. Five keratinocyte-derived signals (stem cell factor,KIT; FOXn1,FGF2; IL-1,, NGF, and p53) are potential candidates to have stimulated the sequential development of epidermal pigmentation in response to stress to the barrier. We summarize evidence here that epidermal interfollicular pigmentation in early hominids likely evolved in response to stress to the permeability barrier. Am. J. Hum. Biol., 2010. © 2010 Wiley-Liss, Inc. [source]

    Differentially expressed proteins in gastrointestinal stromal tumors with KIT and PDGFRA mutations

    Hyun Ju Kang
    Abstract Most gastrointestinal stromal tumors (GIST) have activating mutations in either KIT or PDGFRA. However, a small subset of GIST lacks either mutation. To investigate the molecular characteristics of GIST according to mutation type, protein expression profiles in 12 GIST (2 cases with PDGFRA mutations, 8 cases with KIT mutations and 2 cases lacking either mutation) were analyzed using 2-DE and MALDI-TOF-MS. Comparative analysis of the respective spot patterns using 2-DE showed that 15 proteins were differently expressed according to the mutation status. Expression levels of septin and heat shock protein (HSP) 27 were increased in GIST with KIT mutations and annexin V was overexpressed in GIST lacking either mutation. Among the 15 proteins, overexpression of 5 proteins [annexin V, high mobility group protein 1 (HMGB1), C13orf2, glutamate dehydrogenase 1 and fibrinogen beta chain] and decreased expression of RoXaN correlated with a higher tumor grade. These findings suggest that differential protein expression can be used as a diagnostic biomarker. Moreover, it may play a role in the development and progression of GIST according to activating mutation type, as these proteins have been shown to be involved in tumor metastasis, apoptosis and immune response. [source]

    Aberrant expression of glycosylation in juvenile gastrointestinal stromal tumors

    Tsuyoshi Takahashi
    Abstract Most adult gastrointestinal stromal tumors (GIST) are thought to be caused by activating mutations in the KIT or PDGFRA gene. However, many juvenile GIST lack either mutation and are considered to develop with a different pathogenesis. To investigate the molecular characteristics of juvenile GIST, we analyzed the proteome difference in phosphorylated protein between adult and juvenile GIST. Eleven GIST samples (seven adult cases and four juvenile cases lacking either mutation) were analyzed by using immunostaining and LC-MS/MS. Comparative analysis of tyrosine-phosphorylated protein levels showed that juvenile GIST possessed phosphorylated KIT in spite of lacking mutation in the KIT gene. Moreover, downstream signals of KIT were also activated as in adult GIST. Although, SDS-PAGE gels showed that there was a difference of each KIT bands between adult and juvenile GIST, they became the same after removal of N-glycans or sialic acids. Moreover, one of the most typical enzymes, ST6Gal1, which transfers Neu5Ac residues in ,2-6 linkage to Gal ,1-4GlcNAc units on N-glycans, is significantly less expressed in juvenile GIST. This suggests that the difference in KIT is generated by post-translational modification and may play a role in the progression of juvenile GIST. [source]

    Oncogenic and ligand-dependent activation of KIT/PDGFRA in surgical samples of imatinib-treated gastrointestinal stromal tumours (GISTs),

    T Negri
    Abstract As the range of receptor tyrosine kinase (RTK) inhibitors widens, a detailed understanding of the activating mechanisms of KIT/platelet-derived growth factor receptor (PDGFR)A and the related downstream pathways involved in the development and maintenance of GISTs is becoming increasingly important. We analysed areas with different histological response ratios in surgical specimens taken from imatinib-treated and untreated GIST patients in order to investigate KIT and PDGFRA expression/activation, the presence of their cognate ligands and the activation of downstream signalling, by means of biochemistry, immunohistochemistry and flow cytometry. All of the cases showed KIT and PDGFRA co-expression. In addition to the oncogenic activation of mutated receptors, activation of wild-type KIT and wild-type PDGFRA, sustained by heterodimerization and an autocrine,paracrine loop, was demonstrated by the presence of their specific ligands, stem cell factor (SCF) and PDGFA. To confirm RTK activation further, all of the samples (including those with the highest regression ratios) were investigated for downstream effectors, and all proved to have activated downstream signalling. The results show that after the mutated receptors are switched off, heterologous wild-type receptors become important in imatinib-treated GISTs as a means of maintaining signalling activation. Taken together, our findings suggest that drugs targeting wild-type receptors should be tested in imatinib-treated GIST patients. Copyright © 2008 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd. [source]

    Increased KIT signalling with up-regulation of cyclin D correlates to accelerated proliferation and shorter disease-free survival in gastrointestinal stromal tumours (GISTs) with KIT exon 11 deletions,

    F Haller
    Abstract Gastrointestinal stromal tumours (GISTs) with deletions in KIT exon 11 are characterized by higher proliferation rates and shorter disease-free survival times, compared to GISTs with KIT exon 11 point mutations. Up-regulation of cyclin D is a crucial event for entry into the G1 phase of the cell cycle, and links mitogenic signalling to cell proliferation. Signalling from activated KIT to cyclin D is directed through the RAS/RAF/ERK, PI3K/AKT/mTOR/EIF4E, and JAK/STATs cascades. ERK and STATs initiate mRNA transcription of cyclin D, whereas EIF4E activation leads to increased translation efficiency and reduced degradation of cyclin D protein. The aim of the current study was to analyse the mRNA and protein expression as well as protein phosphorylation of central hubs of these signalling cascades in primary GISTs, to evaluate whether tumours with KIT exon 11 deletions and point mutations differently utilize these pathways. GISTs with KIT exon 11 deletions had significantly higher mitotic counts, higher proliferation rates, and shorter disease-free survival times. In line with this, they had significantly higher expression of cyclin D on the mRNA and protein level. Furthermore, there was a significantly higher amount of phosphorylated ERK1/2, and a higher protein amount of STAT3, mTOR, and EIF4E. PI3K and phosphorylated AKT were also up-regulated, but this was not significant. Ultimately, GISTs with KIT exon 11 deletions had significantly higher phosphorylation of the central negative cell-cycle regulator RB. Phosphorylation of RB is accomplished by activated cyclin D/CDK4/6 complex, and marks a central event in the release of the cell cycle. Altogether, these observations suggest increased KIT signalling with up-regulation of cyclin D as the basis for the unfavourable clinical course in GISTs with KIT exon 11 deletions. Copyright © 2008 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd. [source]

    Amplification of genes encoding KIT, PDGFR, and VEGFR2 receptor tyrosine kinases is frequent in glioblastoma multiforme

    Heikki Joensuu
    Abstract KIT, platelet-derived growth factor receptors (PDGFRs) and vascular endothelial growth factor receptors (VEGFRs) are important clinical targets for tyrosine kinase inhibitors. The frequency of KIT and VEGFR2 amplification in glioblastomas is not known, and few data are available in any other human tumour type. We investigated 43 primary glioblastomas for KIT, VEGFR2, PDGFRA and EGFR amplification using fluorescence in situ hybridization. KIT was amplified in 47% and VEGFR2 in 39% of the glioblastomas, respectively, and PDGFRA in 29%. Thirty-five (81%) of the tumours had either KIT or EGFR amplification. KIT, PDGFRA and VEGFR2 amplifications were strongly associated (p < 0.0001 for each pairwise comparison), suggesting co-amplification, whereas no significant association was found with EGFR amplification. The four secondary glioblastomas arising from pre-existing lower grade astrocytic tumours investigated had KIT amplification but none had EGFR amplification. No mutations were detected with denaturing high-performance liquid chromatography in KIT exons 9, 11, 13 or 17, PDGFRA exons 12 and 18, or EGFR exons 18, 19 or 21. Glioblastomas with KIT, PDGFR or VEGFR2 amplification were associated with similar outcome to other glioblastomas. We conclude that KIT, PDGFRA and VEGFR2 are commonly amplified in primary glioblastoma and that they may also be amplified in secondary glioblastoma. Amplified kinases may be potential targets for tyrosine kinase inhibitor therapy. Copyright © 2005 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd. [source]

    Characterization of the porcine KIT ligand gene: expression analysis, genomic structure, polymorphism detection and association with coat colour traits

    ANIMAL GENETICS, Issue 3 2008
    C. Hadjiconstantouras
    Summary Kit ligand (KITLG) is the ligand for the type III receptor tyrosine kinase KIT. Studies of the KIT/KITLG pathway in a number of mammalian species have shown that it is important for the development of stem cell populations in haematopoietic tissues, germ cells in reproductive organs and the embryonic migrating melanoblasts that give rise to melanocytes. Consequently, mutations in the pathway may result in a range of defects including anaemia, sterility and de-pigmentation. The cDNA sequence of the porcine KITLG gene has been reported previously, and is an attractive candidate locus for moderating coat colour in pigs. In this paper we report the gene structure and physical mapping of the porcine gene. We also report the identification of polymorphisms in the gene, one of which was used to confirm linkage to chromosome 5. Preliminary RNA expression studies using a panel of tissues have shown that in addition to the known variant lacking exon 6, there is alternative splicing of exon 4. However, little evidence was found for the KITLG gene being linked to variation in colour in a Meishan × Large White cross. [source]

    Analysis of the MC1R, KIT and ASIP loci in Chinese and European pigs

    ANIMAL GENETICS, Issue 3 2006
    K. R. Shi
    No abstract is available for this article. [source]

    Mutations in gastrointestinal stromal tumors , a population-based study from Northern Norway,

    APMIS, Issue 4 2007
    Gastrointestinal stromal tumor (GIST) is the most common mesenchymal tumor of the gastrointestinal tract. This tumor typically expresses KIT, and has KIT or PDGFRA activating mutation. In this study we evaluated 89 GISTs diagnosed in Northern Norway during a 30-year period. KIT exons 8, 9, 11, 13, and 17 were analyzed by PCR amplification and direct sequencing. Subsequently PDGRA exons 12, 14, and 18 were evaluated in KIT wild-type cases. KIT mutations were found in 66 cases (75%), and PDGFRA mutations in 9 cases (10%). Most common were KIT exon 11 mutations, with 58 cases. Tumors with Kit exon 11 point mutations had a significantly better prognosis than those with deletions. There were five KIT exon 9 duplications, three exon 13 point mutations, and one point mutation in exon 17. There were nine PDGFGRA mutations: seven in exon 18 and two in exon 12. All but one PDGFRA mutant GISTs were gastric tumors with epithelioid morphology, and these tumors were on average smaller than those with KIT mutations. KIT and PDGFRA wild type was found in 15% of cases. Analysis of KIT and PDGFRA mutations is of significance for treatment with tyrosine kinase inhibitors, and may also have value when assessing the biological potential of GIST. [source]

    Laparoscopic resection of extra-gastrointestinal stromal tumor of the transverse mesocolon

    N Asakage
    Abstract The patient was a 58-year-old man. A recent complete work-up was done to find the cause of epigastric pain and revealed a nodule about 4 cm in diameter in the upper right abdomen on CT scans. Laparoscopic resection was performed to allow for a definitive diagnosis to be made and to treat the lesion. The tumor was located in the transverse mesocolon, and there was no communication between the lesion and the ascending or transverse colon. Spindle-shaped tumor cells were arranged in palisades. The number of mitotic figures was only 1/50 HPF. The tumor was weakly positive for KIT and negative for CD34. From these findings, a diagnosis of extra-gastrointestinal stromal tumor originating in the transverse mesocolon was made. [source]


    Article first published online: 27 OCT 200


    Lou Farnworth
    No abstract is available for this article. [source]