Canine Central Nervous System Neoplasm Phenotyping Using Tissue Microarray Technique

Abstract

Tissue microarrays (TMAs) represent a useful technique for the simultaneous phenotyping of large sample numbers and are particularly suitable for histopathologic tumor research. In this study, TMAs were used to evaluate semiquantitatively the expression of multiple antigens in various canine central nervous system (CNS) neoplasms and to identify markers with potential discriminative diagnostic relevance. Ninety-seven canine CNS neoplasms, previously diagnosed on hematoxylin and eosin sections according to the World Health Organization classification, were investigated on TMAs, with each tumor consisting of 2 cylindrical samples from the center and the periphery of the neoplasm. Tumor cells were phenotyped using a panel of 28 monoclonal and polyclonal antibodies, and hierarchical clustering analysis was applied to group neoplasms according to similarities in their expression profiles. Hierarchical clustering generally grouped cases with similar histologic diagnoses; however, gliomas especially exhibited a considerable heterogeneity in their positivity scores. Multiple tumor groups, such as astrocytomas and oligodendrogliomas, significantly differed in the proportion of positive immunoreaction for certain markers such as p75, AQP4, GFAP, and S100 protein. The study highlights AQP4 and p75 as novel markers, helping to discriminate between canine astrocytoma and oligodendroglioma. Furthermore, the results suggest that p75 and proteolipid protein may represent useful markers, whose expression inversely correlates with malignant transformation in canine astrocytomas and oligodendrogliomas, respectively. Tissue microarray was demonstrated to be a useful and time-saving tool for the simultaneous immunohistochemical characterization of multiple canine CNS neoplasms. The present study provides a detailed overview of the expression patterns of different types of canine CNS neoplasms.

Meningioma and associated cerebral infarction in three dogs

“…For further evaluation of the meningiomas, immunohistochemistry for vimentin (Vimentin, monoclonal mouse, diluted 1:100, Dako, Santa Clara, USA), pancytokeratin (AE1/AE3, monoclonal mouse, diluted 1:500, Dako), glial fibrillary acidic protein (GFAP, polyclonal rabbit, diluted 1:1000, Dako) or S-100 protein (S-100, polyclonal rabbit, diluted 1:800, Sigma-Aldrich, St. Louis, USA) using the avidin-biotin-peroxidase complex (ABC) method (Vector Laboratories, Burlingame, USA) was performed. In case 2, additionally immunohistochemistry detecting neuron specific enolase (NSE, monoclonal mouse, diluted 1:100, Dako) and laminin (Laminin, polyclonal rabbit, diluted 1:75, quartett GmbH, Berlin, Germany) were applied [13].…”

Ependymoma in a dwarf goat

“…It represents also an important point for the exclusion of an oligodendroglioma as the main differential diagnosis of cellular ependymomas. Oligodendrogliomas usually lack expression of GFAP [2] [13], but might occasionally stain positive for 2´3´-cyclic-nucleotide 3´-phosphodiesterase (CNPase) as it has been shown in a study about the immunophenotype of 97 canine CNS neoplasms [24], while ependymomas, to the best of the authors' knowledge, do not [24]. The negative result for the CNPase-antibody also constitutes a hint in opposition of the diag-nosis of an oligodendroglioma.…”

“…For immunohistochemistry (IHC), dewaxed tissue sections were processed as described previously [24]. Briefly, unstained sections were dewaxed and rehydrated in a descending series of alcohol.…”

Microtubule-Associated Protein 2 Expression in Canine Glioma

“…Based on these findings, MAP2 appears to be a suitable diagnostic immunohistochemical marker for canine glioma, with strong potential of aiding in the diagnosis of astrocytoma based on the pattern of immunolabeling. However, the number of cases exhibiting multifocal to coalescing (16/78; 20.5%) and patchy immunolabeling (20/78; 26%) illustrate the heterogeneity present in these tumors and raise a concern that the use of tissue microarray for immunohistochemical analysis in canine glioma may yield results that are not entirely representative of the totality of the neoplasm (33, 38). The three cases of astrocytoma with PNc and Ct staining were all from one location (the cerebellar white matter) and had an unusual pattern composed of sheets of gemistocyte-like morphology.…”