• Open Access

Expression of KIT Receptor Tyrosine Kinase in Endothelial Cells of Juvenile Brain Tumors

Authors

  • Marjut Puputti MSc,

    1. Helsinki Biomedical Graduate School, Helsinki, Finland.
    2. Laboratory of Molecular Oncology, Biomedicum Helsinki, Helsinki, Finland.
    3. The Finnish Programme for Centres of Excellence in Research, Host Defence Research, Turku, Finland.
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    • These authors have contributed equally to this study.

  • Olli Tynninen MD,

    1. Department of Pathology, Helsinki University Central Hospital (HUSLAB) and University of Helsinki, Helsinki, Finland.
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    • These authors have contributed equally to this study.

  • Paula Pernilä BSc,

    1. Laboratory of Molecular Oncology, Biomedicum Helsinki, Helsinki, Finland.
    2. The Finnish Programme for Centres of Excellence in Research, Host Defence Research, Turku, Finland.
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  • Marko Salmi MD, PhD,

    1. The Finnish Programme for Centres of Excellence in Research, Host Defence Research, Turku, Finland.
    2. MediCity Research Laboratory, University of Turku, Turku, Finland.
    3. Department of Medical Biochemistry, University of Turku, Turku, Finland.
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  • Sirpa Jalkanen MD, PhD,

    1. The Finnish Programme for Centres of Excellence in Research, Host Defence Research, Turku, Finland.
    2. MediCity Research Laboratory, University of Turku, Turku, Finland.
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  • Anders Paetau MD, PhD,

    1. Department of Pathology, Helsinki University Central Hospital (HUSLAB) and University of Helsinki, Helsinki, Finland.
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  • Harri Sihto MSc,

    1. Laboratory of Molecular Oncology, Biomedicum Helsinki, Helsinki, Finland.
    2. The Finnish Programme for Centres of Excellence in Research, Host Defence Research, Turku, Finland.
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  • Heikki Joensuu MD, PhD

    Corresponding author
    1. Laboratory of Molecular Oncology, Biomedicum Helsinki, Helsinki, Finland.
    2. Department of Oncology, Helsinki University Central Hospital, Helsinki, Finland.
    3. Molecular Cancer Biology Program, University of Helsinki, Biomedicum Helsinki, Finland.
    4. The Finnish Programme for Centres of Excellence in Research, Host Defence Research, Turku, Finland.
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Heikki Joensuu, MD, PhD, Department of Oncology, Helsinki University Central Hospital, Haartmaninkatu 4, PO Box 180, FIN-00029 Helsinki, Finland (E-mail: heikki.joensuu@hus.fi)

Abstract

KIT receptor tyrosine kinase is expressed in tumor endothelial cells of adult glioblastomas, but its expression in pediatric brain tumor endothelial cells is unknown. We assessed expression of KIT, phosphorylated KIT, stem cell factor (SCF) and vascular endothelial growth factor receptor-2 (VEGFR-2) in 35 juvenile pilocytic astrocytomas and 49 other pediatric brain tumors using immunohistochemistry, and KIT messenger RNA (mRNA) using in situ hybridization. KIT and phospho-KIT were moderately or strongly expressed in tumor endothelia of 37% and 35% of pilocytic astrocytomas, respectively, whereas marked SCF and VEGFR-2 expression was uncommon. KIT mRNA was detected in tumor endothelial cells. Tumor endothelial cell KIT expression was strongly (P < 0.01) associated with endothelial cell phospho-KIT and SCF expression, and with tumor KIT (P = 0.0011) and VEGFR-2 expression (P = 0.022). KIT and phospho-KIT were present in endothelia of other pediatric brain tumors, notably ependymomas. Endothelial cell KIT expression was associated with a young age at diagnosis of pilocytic astrocytoma or ependymoma, and it was occasionally present in histologically normal tissue of the fetus and children. We conclude that KIT is commonly present in endothelial cells of juvenile brain tumors and thus may play a role in angiogenesis in these neoplasms.

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