Cellular Proliferative and Telomerase Activity in Canine Mammary Gland Tumors

Abstract

In canine mammary tumors, we examined the telomerase activity, proliferative activity by proliferative cell nuclear antigen (PCNA) immunohistochemistry, and percentage of apoptotic cells by the deoxynucleotidyl transferase-mediated dUTP-biotin nick end-labeling (TUNEL) method. The relationship between these measures and histopathologic malignancy was also investigated. PCNA index was highest in malignant tumors (adenocarcinoma: 27.0%; malignant mixed tumor: 15.7%), followed by benign tumors (adenoma: 4.4%; benign mixed tumor: 5.3%), hyperplasia (2.1%), and normal mammary gland (0.9%). In adenoma and adenocarcinoma, papillary and solid types showing higher cellularity tended to have higher PCNA indices than did cystic and tubular types. Although the TUNEL index was <1% in all cases, the relationship between this measure and histopathologic diagnosis showed the same tendency as observed in PCNA immunostaining. Telomerase activity was detectable in all adenomas, benign mixed tumors, and adenocarcinomas examined. In contrast, all normal mammary glands, hyperplasias, and malignant mixed tumors were negative for telomerase. Relative telomerase activity (RTA) of adenocarcinoma (56.5) was significantly higher than that of adenoma (27.8) and benign mixed tumor (33.9), and a significant positive correlation (P < 0.001) was noted between RTA and PCNA index. No significant correlations were noted between either PCNA or TUNEL index and clinical features such as metastasis and tumor diameter. PCNA index and telomerase activity may be useful markers for judging malignancy of canine mammary tumors.

Multiple mammary tumours in a bitch: analysis of mitotic index, AgNOR count and c-erbB2 expression status: a case report

“…The histological types found in this case were also reported by other researchers (Misdorp et al, 1999;Funakoshi et al, 2000;Reddy et al, 2009) but mostly in solitary cases. The mitotic index revealed that the tumour mass had a good proportion of cells in the M-phase of the cell cycle.…”

Telomerase: A Potential Diagnostic and Therapeutic Tool in Canine Oncology

“…30,34,42 The presence of telomerase activity in canine tumor tissues has been reported by a number of investigators. 2,13,42,43 Taken together, these four studies have analyzed over 100 canine solid tumors for telomerase activity and have demonstrated that more than 95% of all canine cancers are associated with telomerase activity. Table 1 summarizes the telomerase assessment of canine tumors from three studies.…”

“…A number of investigators are now focusing their attention on telomerase and its role in canine oncology in an attempt to discern whether telomerase is ubiquitously expressed in canine tumors and may represent a promising target for therapeutic intervention. 2,13,34 Canine telomeres consist of large heterogeneous repeats ranging from 3 to 23 kbp in length. 34,42 Telomeric attrition has not only been demonstrated during in vitro aging of canine fibroblast cultures but telomeric instability has also been documented in vivo.…”

Köpek Meme Tümörlerinde Bcl-2, Bcl-XL ve Bax Sunulumu İle Apoptotik İndeksin Değerlendirilmesi

“…The evaluation of malignancy potential and prognosis is important for the treatment of CMT. Nevertheless the histopathological diagnosis, which is accepted as the best way for the classification of CMT, sometimes can be insufficient for the definition of prognosis because of tumours' complicated histological types and their different biological behaviours [4,6] . Thereby, in recent years the interest on novel markers such as growth and proliferation factors and apoptosis related genes and proteins is increasing in order to make more reliable diagnosis and to estimate of prognosis and biological behaviours of CMT.…”