Telomerase is a ribonucleoprotein complex that prevents the erosion of chromosomal extremities (telomeres) in eukaryotic cells. The role of telomerase in the process of tumoural transformation is currently undergoing intense scrutiny, as its activation is considered a fundamental step in “immortalization” of neoplastic cells, and has been suggested to play a key role in the progression of several tumours, including human intracranial meningiomas. This study aimed to evaluate in 25 cases of archived meningiomas (14 canine and 11 feline) the presence of telomerase, determined by immunohistochemistry (IHC) with an anti-h-TERT monoclonal antibody (clone 44F12, Novocastra), which detects the enzymatic catalytic subunit. The positive reaction, identified by the evidence of scattered nuclear and/or nucleolar staining, was computed with an automated image analysis system ("Lucia 32G/Mutech", Nikon) and expressed as percentage of positive tumoural cells. According to WHO International Classification of Tumors of the Nervous System of Domestic Animals, meningiomas were grouped into the following histotypes: meningothelial (6 canine), transitional/mixed (1 canine, 6 feline), psammomatous (1 canine, 2 feline), fibrous/fibroblastic (1 canine, 1 feline), anaplastic/malignant (5 canine, 2 feline). In 15 out of 25 meningiomas (6 canine, 9 feline) h-TERT protein was localized in the nuclei, notably nucleoli and occasionally in the cytoplasm (two cases) of the cells, with mild to strong staining intensity. Even the percentage of positive cells was variable, ranging from 5 to 80%, regardless of the histological type. Although the number of telomerase-negative meningiomas may depend upon overfixation, the heterogeneous h-TERT expression suggests the existence of alternative mechanisms to telomerase involved in the tumoural transformation and prompts the necessity to correlate h-TERT expression with proliferative activity and biologic behaviour.
Telomerase Reverse Transcriptase (h-TERT) immunohistochemistry in canine and feline meningiomas / L. Mandrioli; S. Panarese; A. Cesari; M. T. Mandara; P. S. Marcato; G. Bettini. - STAMPA. - (2006), pp. 173-174. (Intervento presentato al convegno 24th Meeting of ESVP tenutosi a Edinburgh, Scotland nel 31 agosto-2 settembre 2006).
Telomerase Reverse Transcriptase (h-TERT) immunohistochemistry in canine and feline meningiomas
MANDRIOLI, LUCIANA;PANARESE, SERENA;CESARI, ALESSANDRO;MARCATO, PAOLO STEFANO;BETTINI, GIULIANO
2006
Abstract
Telomerase is a ribonucleoprotein complex that prevents the erosion of chromosomal extremities (telomeres) in eukaryotic cells. The role of telomerase in the process of tumoural transformation is currently undergoing intense scrutiny, as its activation is considered a fundamental step in “immortalization” of neoplastic cells, and has been suggested to play a key role in the progression of several tumours, including human intracranial meningiomas. This study aimed to evaluate in 25 cases of archived meningiomas (14 canine and 11 feline) the presence of telomerase, determined by immunohistochemistry (IHC) with an anti-h-TERT monoclonal antibody (clone 44F12, Novocastra), which detects the enzymatic catalytic subunit. The positive reaction, identified by the evidence of scattered nuclear and/or nucleolar staining, was computed with an automated image analysis system ("Lucia 32G/Mutech", Nikon) and expressed as percentage of positive tumoural cells. According to WHO International Classification of Tumors of the Nervous System of Domestic Animals, meningiomas were grouped into the following histotypes: meningothelial (6 canine), transitional/mixed (1 canine, 6 feline), psammomatous (1 canine, 2 feline), fibrous/fibroblastic (1 canine, 1 feline), anaplastic/malignant (5 canine, 2 feline). In 15 out of 25 meningiomas (6 canine, 9 feline) h-TERT protein was localized in the nuclei, notably nucleoli and occasionally in the cytoplasm (two cases) of the cells, with mild to strong staining intensity. Even the percentage of positive cells was variable, ranging from 5 to 80%, regardless of the histological type. Although the number of telomerase-negative meningiomas may depend upon overfixation, the heterogeneous h-TERT expression suggests the existence of alternative mechanisms to telomerase involved in the tumoural transformation and prompts the necessity to correlate h-TERT expression with proliferative activity and biologic behaviour.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
