Immunohistochemical expression of h-telomerase reverse transcriptase in canine and feline meningiomas

Abstract

Telomere length maintenance is regarded as a fundamental step in tumorigenesis, as most human brain tumors, including meningiomas, stabilize the ends of their chromosomes using telomerase. This investigation represents an introduction to telomerase expression in canine and feline meningiomas. Twenty-five archived cases (14 dogs and 11 cats) were immunohistochemically tested for human-telomerase reverse transcriptase (h-TERT), scored, and quantified; furthermore, mitoses were counted on sections stained with a modified toluidine blue. The h-TERT antibody immunolabelled the nucleus and nucleolus of meningeal neoplastic cells, with an intensity ranging from mild to strong and a speckled distribution; a significantly higher expression in cats was noted, while no significant association between h-TERT immunolabelling and sex or histotype was evident in dogs or cats. The telomerase enzyme represents a fundamental parameter of potential malignant transformation, which may occur independently of the signal to proliferate, thereby supplying the cells with unlimited growth capabilities. Telomerase expression could be a prognostic indicator independent of the kinetic parameters, although this should be evaluated using a larger dataset with available clinical information.

Prognostic Value of Histologic and Immunohistochemical Features in Feline Cutaneous Mast Cell Tumors

“…Maintenance of telomere length by telomerase is a carcinogenetic mechanism for many neoplasms. 8,16,23,28,37 Mast cell precursors undergo transient growth factor-mediated induction of telomerase activity during differentiation. 6 Human MCT cell lines tend to maintain a persistently high telomerase activity, uninfluenced by protein kinase or cell cycle inhibitors.…”

“…23,28 Human mast cell precursors have transient induction of telomerase activity, 6 but telomerase expression in feline MCTs has not been assessed.…”

Advances in Diagnostic and Treatment Modalities for Intracranial Tumors

“…The cellular immortality‐related gene telomerase reverse transcriptase has been shown to be expressed in a variety of canine and feline brain tumors, and similar to human tumors has been associated with tumor grade 119, 120, 121. Similarly, overexpression of MMP‐2 and ‐9, E‐cadherin, claudin‐1, IL‐6, and cyclooxygenase‐2 has been documented in canine and feline meningiomas,121, 122, 123, 124, 125, 126 and MMP‐2/9 has been identified in canine gliomas and choroid plexus tumors 125.…”

Matrix Metalloproteinase-2 and Matrix Metalloproteinase-9 Expression in Canine and Feline Meningioma

“…25 Canine normal testis was used as a positive control for h-TERT. 26 An isotype-matched IgG negative control was run on each section.…”

“…It has been reported that a high proliferative index in the tumor is associated with low progesterone receptor (PR) concentration, suggesting that PR expression in canine and feline meningiomas is a reliable prognostic factor in the evaluation of this tumor, as well as in humans. 2,12,25,46 More recently, canine and feline meningiomas have been tested for telomerase immunoreactivity 22,26 and have produced contradictory results as to the correlation with the proliferative index.…”