The University of Georgia College of Veterinary Medicine

Georgia Veterinary Scholars Program

GVSP Summer 2009 Scholars

Georgia Veterinary Scholar

Faculty Mentor

Amy Yanke
University of Georgia
Class of 2012

Dr. Simon Platt
Deparment of Small Animal Medicine & Surgery

UGA College of Veterinary Medicine

Expression of Heat Shock Proteins, Ki67 and Vascular Endothelial Growth Factor in Canine Astrocytomas and Oligodendrogliomas

* A.B. Yanke,1 S.R. Platt,1 E.W. Howerth2
Department of Small Animal Medicine and Surgery1, and Department of Pathology2, University of Georgia, College of Veterinary Medicine, Athens, GA

Human brain tumors express Heat Shock Proteins (HSP), which are associated with their degree of malignancy. HSPs serve various roles in cell differentiation and proliferation during the normal cell cycle. Their up-regulation during tumor cell growth helps keep tumor proteins stable and therefore makes them a reasonable target for therapy. The aim of this study was to determine if canine astrocytomas and oligodendrogliomas express HSP 27, 72 and/or 90. An additional aim was to determine whether the expression of the HSPs was associated with Ki67 and/or Vascular Endothelial Growth Factor (VEGF) expression. Ki67 expression and VEGF up-regulation have been strong indicators of cell proliferation and angiogenesis during tumor growth, respectively. Twenty-two formalin-fixed, paraffin-embedded canine brain tumors (8 astrocytomas, 2 oligoastrocytomas and 12 oligodendrogliomas) underwent immunohistochemical staining using anti-HSP 27, 72 or 90 antibodies. These tumor samples were also immunohistochemically stained for Ki67 and VEGF expression. Canine mammary carcinoma and squamous cell carcinoma tissues served as the control samples, as both have previously been shown to express HSPs. Four non-overlapping high power fields of each stained sample were selected and cell staining was analyzed using a semi-quantitative method. Preliminary data suggests variable expression of each HSP (HSP 27: 0-30.57%, median 1.56%; HSP 72: 0-58.41%, median 0%; HSP 90: 0-11.13%, median 1.31%) in these tumors. Further analysis is underway to determine associations with VEGF and Ki67 expression. This study increases our knowledge about the functional proteins expressed on canine brain tumors with the hope to ultimately improve their specific targeted therapy.