Diagnostic Immunohistochemistry of Canine and Feline Intracalvarial Tumors in the Age of Brain Biopsies

Abstract

The focus of immunohistochemistry as applied to nervous system tumors is in identifying the neoplasm present and evaluating margins between normal and neoplastic tissue. Although not always utilized by specialists in neuropathology, immunohistochemistry remains useful to resolve concerns about the differentiation and rate of tumor growth. The aims of this review are to discuss the utility of immunohistochemical reagents currently used in diagnosis of canine and feline intracalvarial tumors, to indicate the applicability of some tests currently used in human nervous system tumors for domestic species, and to evaluate a few less commonly used reagents. A panel of biomarkers is usually needed to confirm a diagnosis, with groups of reagents for leptomeningeal, intraparenchymal, and ventricular neoplasms. In the future, signature genetic alterations found among feline and canine brain tumors-as correlated prospectively with diagnosis, rate of enlargement, or response to treatment-may result in new immunohistochemical reagents to simplify the task of diagnosis. Prospective studies determining the type and proportion of stem cell marker expression on patient longevity are likely to be fruitful and suggest new therapies. Due to increased frequency of biopsy or partial resection of tumors from the living patient, biomarkers are needed to serve as accurate prognostic indicators and assist in determining the efficacy of developing therapeutic options in nervous system tumors of dogs and cats.

Periocular extracranial cutaneous meningiomas in two dogs

“…Meningiomas do not present a specific immunohistochemical staining pattern but canine tumors are usually vimentin and S100 positive, GFAP negative, and stain variably with pancytokeratins. 1,4,10,13 The immunohistochemical staining pattern of tumors presented herein (vimentin and focal S100 positivity and pancytokeratin and GFAP negativity) are consistent with meningiomas. Epithelial membrane antigen has been found very useful in distinguishing human meningiomas from other spindle cell tumors, but no reagents are available for routine veterinary samples.…”

A comparison of clinical, magnetic resonance imaging and pathological findings in dogs with gliomatosis cerebri, focusing on cases with minimal magnetic resonance imaging changes‡

“…Olig2 immunohistochemistry is an emerging but previously validated tool in canine brain tumours . It should be noted that astrocytes and oligodendrocytes share a common precursor, and although normal and reactive astrocytes are Olig2‐negative, Olig2‐positive neoplastic cells have been detected in astrocytic tumours of dogs, cats and people . Critically, all such astrocytic tumours were also GFAP‐positive .…”

“…Normal astrocytes in non‐neoplastic brain tissue were used as an internal positive control. The use of this anti‐bovine antibody for canine brain tumours is well accepted …”

“…Sections were then incubated with the primary antibody, rabbit polyclonal antibody to recombinant mouse Olig2 (AB9610, EMD Millipore, Billerica, MA, USA), diluted 1:500, for 1 h 30 min. The use of this anti‐murine antibody for canine brain tumours has been reported . After three washes with tris‐buffered saline, sections were incubated for 40 min with a rabbit‐on‐canine horseradish peroxidase‐labelled polymer detection system (PromARK, Biocare Medical).…”

Clinical, Imaging and Pathological Characteristics of Brain Implanted Polylactic Co-Glycolic Acid Polymers Conjugated with Temozolomide

“…Meningiomas, the most common primary brain tumour of dogs [4,5] have shown good response to more extensive surgical resection [6][7][8] and both conventional and stereotactic radiation therapy [9,10]. Glial tumours arise from the neuroectoderm and most notably include low-grade astrocytomas, oligodendrogliomas, and glioblastoma multiforme, representing 17%, 13% and 3% of primary canine brain tumours respectively [5,11,12].…”