Canine mammary tumors (CMT) represent the most common cancer in noncastrated female dogs. Interestingly, triple-negative tumors are the most common molecular subtype in female dogs. In this study, we proposed to evaluate the expression of vascular endothelial growth factor receptor 2 (VEGFR-2), Platelet-derived growth factor receptor (PDGFR), and microvascular density (MVD) in a group of metastatic and nonmetastatic triple-negative CMT and compare the expression based on clinical parameters. Twenty-six female dogs with triple-negative mammary tumors were divided into three groups: nonmetastatic tumors (NMT) (n = 11), tumors with lymph node metastasis (LNM) (n = 10), and tumors with lung metastasis (LM) (n = 5). We observed increased VEGFR-2 expression in LNM compared with NMT and a positive correlation between tumor grade and VEGFR-2 expression. A positive correlation was noted between VEGFR-2 and PDGFR expression. Regarding microvascular density (MVD), we identified a higher number of vessels in primary tumors with lymph node metastasis and lung metastasis compared with tumors with no metastasis. The primary tumors with lung metastasis exhibited an increased MVD compared with carcinoma with lymph node metastasis. Overall, our results suggest a deregulation of VEGFR-2 and PDGFR and high MVD in metastatic tumors, indicating a role for angiogenesis in tumor progression.

Background: Hemostatic alterations are commonly detected in canine cancer patients. However, few studies have described hemostatic dysfunction in dogs with different tumor subtypes. In Veterinary Medicine, the state of hypercoagulability is hardly diagnosed alive, since laboratory exams for evaluate hemostatic function are not always requested. Due to importance of homeostatic disorders in cancer patients, this study aimed to evaluate hemostatic alterations such as platelet count, activated partial thromboplastin time (aPTT), prothrombin time (PT) and fibrinogen in tumor-bearing dogs.Materials, Methods & Results: From the 55 dogs evaluated, 30 had mammary carcinoma, 6 visceral hemangiosarcoma, 9 high-grade cutaneous mast cell tumor and 10 multicentric lymphoma. The results were compared to a control group composed by 10 Beagle dogs. Thrombocytosis was observed in 26.6% (8/30) of mammary carcinoma group and thrombocytopenia in 10% (3/30). The patients with hemangiosarcoma and mast cell tumor did not reveal thrombocytosis, however, thrombocytopenia was present in 16.6% (1/6) and 33% (3/9), respectively. Three dogs with multicentric lymphoma showed thrombocytopenia and other three showed thrombocytosis. From patients with thrombocytosis, one was classified as severe thrombocytosis (1077 x 10³/µL). Therefore, there were no statistically significant associations between neoplasia group with control group (P > 0.05). Regarding the aPTT and PT evaluation, mammary carcinoma (P = 0.0005), hemangiosarcoma (P = 0.033) and mast cell tumor (P = 0.012) patients showed statistical difference for aPTT, while the evaluation for PT was not significant (P > 0.05). We grouped all patients as a “tumor group” and compared to the control group. It was possible to observe increased aPTT and PT in 89% (49/55) and 50.90% (28/55) respectively, in tumor group compared to normal. A total of 47.27% (n = 26) of the patients with tumors presented increased aPTT and PT concomitantly. In the present study, 14.54% of the patients presented elevated levels of fibrinogen associated with increased aPTT. However, only the mast cell tumor group was statistically significant (P = 0.043).Discussion: Hemostatic alterations can be found in dogs with cancer and when these alterations occurs, can be directly associated with tumoral non-invasive actions called as paraneoplastic syndrome. However, the hemostatic paraneoplastic syndrome is poorly reported in veterinary medicine, with limited number of papers describing this condition. Our results indicated that the presence of thrombocytosis in patients with tumors could be related with the production of granulocytemacrophage colony stimulating factors (GM-CSF) and IL-6 by tumor cells. A total of 26 patients with tumors presented increased aPTT and PT concomitantly, confirming that hemostatic dysfunction is a common alteration in dogs with neoplasia. However, despite alterations in coagulation parameters, there were no clinical manifestations of bleeding such as petechial or bruising in these patients. The increased fibrinogen and aPTT can be caused by a systemic inflammatory reaction mediated by pro-inflammatory cytokines produced by tumors cells. Based on that, 14.54% of the animals presented elevated levels of fibrinogen associated with elevated aPTT suggesting that these patients are associated with systemic inflammation and tumor progression. This study suggested that bearing-tumors patients shows important hemostatic dysfunctions, elucidating the clinical importance of these results in veterinary medicine.

Canine mammary tumors (CMT) are the most common cancer in noncastrated female dogs. Interestingly, triple-negative tumors are the most common molecular subtype in female dogs. In this study, we proposed to evaluate the expression of VEGFR-2, PDGFR and microvascular density (MVD) in a group of metastatic and nonmetastatic triple-negative CMT and compare the expression based on clinical parameters. Twenty-six female dogs with triple-negative mammary tumors were divided into three groups: nonmetastatic tumors (NMT) (N=11), tumors with lymph node metastasis (LNM) (N=10) and tumors with lung metastasis (LM) (N=5). We observed increased VEGFR-2 expression in LNM compared with NMT and a positive correlation between tumor grade and VEGFR-2 expression. A positive correlation was noted between VEGFR-2 and PDGFR expression. Regarding microvascular density (MVD), we identified a higher number of vessels in primary tumors with lymph node metastasis and lung metastasis compared with tumors with no metastasis. The primary tumors with lung metastasis exhibited an increased MVD compared with carcinoma with lymph node metastasis. Overall, our results suggest a deregulation of VEGFR-2 and PDGFR and high MVD in metastatic tumors, indicating a role for angiogenesis in tumor progression.

Canine mammary tumors (CMT) are the most common cancer in noncastrated female dogs. Interestingly, triple-negative tumors are the most common molecular subtype in female dogs. In this study, we proposed to evaluate the expression of VEGFR-2, PDGFR and microvascular density (MVD) in a group of metastatic and nonmetastatic triple-negative CMT and compare the expression based on clinical parameters. Twenty-six female dogs with triplenegative mammary tumors were divided into three groups: nonmetastatic tumors (NMT) (N=11), tumors with lymph node metastasis (LNM) (N=10) and tumors with lung metastasis (LM) (N=5). We observed increased VEGFR-2 expression in LNM compared with NMT and a positive correlation between tumor grade and VEGFR-2 expression. A positive correlation was noted between VEGFR-2 and PDGFR expression. Regarding microvascular density (MVD), we identified a higher number of vessels in primary tumors with lymph node metastasis and lung metastasis compared with tumors with no metastasis. The primary tumors with lung metastasis exhibited an increased MVD compared with carcinoma with lymph node metastasis. Overall, our results suggest a deregulation of VEGFR-2 and PDGFR and high MVD in metastatic tumors, indicating a role for angiogenesis in tumor progression. Key-words: angiogenesis. metastasis. mammary neoplasm. 1. Misdorp, W. Tumors of the mammary gland. In Tumors in Domestic Animals, 4th ed.; Meuten, D.J., Eds.; Iowa State Press: Ames, IA, USA, 2002, pp. 575-606. 2. Sorenmo, K.U.; Worley, D.R.; Goldschmidt, M.H. Tumors of the Mammary Gland. In Withrow & MacEwen's Small Animal Clinical Oncology, 5th ed.; Withrow S.J., Vail D.M., Page R.L., Eds.; Elsevier: St Louis, MO, USA, 2013, pp. 538-556. 3. DE NARDI, A.B.; RODASKI, S.; SOUSA, R.S.; COSTA, T.A.; MACEDO, T.R.; RODIGHERI, S.M.; RIOS, A.; PIEKARZ, C.H. Prevalência de neoplasias e modalidades de tratamentos em cães, atendidos no hospital veterinário da Universidade Federal do Paraná. Arch Vet Sci. 2002, 7, 15-26; http://dx.doi.org/10.5380/avs.v7i2.3977 4. Santos, I.F.C.; Cardoso, J.M.M.; Oliveira, K.C.; Laisse, C. J. M.; Bessa, S.A.T. Prevalência de neoplasias diagnosticadas em cães no Hospital Veterinário da Universidade Eduardo Mondlane, Moçambique. Arq Bras Med Vet Zootec. 2013, 65, 773-782; http://dx.doi.org/10.1590/S0102-09352013000300025 5. Bray, F.; Ferlay, J.; Soerjomataram, I.; Siegel, R.L.; Torre, L.A.; Jemal, A. Global cancer statistics 2018: GLOBOCAN estimates of incidence and mortality worldwide for 36 cancers in 185 countries. CA Cancer J Clin. 2018, 68, 394-424; https://doi.org/10.3322/caac.21492 PTEN and VEGF in canine mammary gland tumours. Vet Res Commun. 2008, 32, 463-72; https://doi.org/10.1007/s11259-008-9049-7 12. Santos, A.; Lopes, C.; Gärtner, F.; Matos, A.J. VEGFR-2 expression in malignant tumours of the canine mammary gland: a prospective survival study. Vet Comp Oncol. 2016, 14, 83-92; https://doi.org/10.1111/vco.12107 13. Cristofanilli, M.; Morandi, P.; Krishnamurthy, S.; Reuben, J.M.; Lee, B.N.; Francis, D.; Booser, D.J.; Gree...