Transmissible venereal tumor of the uterine stump following successful chemotherapy in a 5-year-old mixed-breed dog.

A 5-year-old spayed female mixed-breed dog was referred to the Atlantic Veterinary College (Charlottetown, Prince Edward Island) because of a 7-month history of intermittent pink, mucoid, vulvar discharge. The dog was imported from the Bahamas at 3.5 y of age and had a history of transmissible venereal tumor (TVT) of the vulva that was successfully treated with a course of vincristine chemotherapy. Complete remission was achieved with a disease-free interval of 6 mo before clinical signs recurred. Abdominal ultrasound and CT scan identified a large caudal abdominal mass thought to arise from the uterine stump. An exploratory laparotomy was performed and the mass grossly excised. Histopathology was consistent with a poorly differentiated round cell tumor, and immunohistochemical analysis confirmed TVT as the most likely diagnosis. No further treatment was carried out. Repeat abdominal ultrasound at 4 mo after surgery showed no evidence of mass recurrence. At 8 mo after surgery, the dog was reported to be doing well clinically. Key clinical message: Transmissible venereal tumor should be considered as a differential diagnosis for masses arising from the deep genital tissues of dogs in cases where there is a history of previous TVT. Transmissible venereal tumor should be considered even in dogs that have had complete resolution of a primary mass after chemotherapy.

Tumeur vénérienne transmissible du moignon utérin à la suite d'une chimiothérapie réussie chez un chien croisé de 5 ans.Une chienne de race mixte de 5 ans, stérilisée, a été référée au Atlantic Veterinary College (Charlottetown, Île-du-Prince-Édouard) en raison d'antécédents de pertes vulvaires roses, mucoïdes et intermittentes depuis 7 mois. Le chien a été importé des Bahamas à l'âge de 3,5 ans et avait des antécédents de tumeur vénérienne transmissible (TVT) de la vulve qui a été traitée avec succès par une chimiothérapie à la vincristine. Une rémission complète a été obtenue avec un intervalle sans maladie de 6 mois avant la réapparition des signes cliniques. L'échographie abdominale et la tomodensitométrie ont identifié une grosse masse abdominale caudale qui proviendrait du moignon utérin. Une laparotomie exploratoire a été réalisée et la masse excisée. L'histopathologie était compatible avec une tumeur à cellules rondes peu différenciée et l'analyse immunohistochimique a confirmé la TVT comme le diagnostic le plus probable. Aucun autre traitement n'a été effectué. Une échographie abdominale répétée 4 mois après la chirurgie n'a montré aucun signe de récidive massive. Huit mois après l'opération, la chienne se portait bien cliniquement.Message clinique clé:Les tumeurs vénériennes transmissibles doivent être considérées comme un diagnostic différentiel pour les masses provenant des tissus génitaux profonds des chiens dans les cas où il existe des antécédents de TVT. Une tumeur vénérienne transmissible doit être envisagée même chez les chiens dont la masse primaire a complètement disparu après chimiothérapie.(Traduit par Dr Serge Messier).

Canine transmissible venereal tumor in Morocco: Clinical and pathological findings in 64 dogs-insights from a descriptive epidemiological study (2020-2023).

Background: Canine transmissible venereal tumor (CTVT) is a widely spread, contagious neoplasm commonly found in dogs. Mostly affects the external genitalia, however, it may also exhibit unusual clinical presentations. Aim: To describe the epidemiology, clinical appearance, cytologic and histopathologic features of dogs with TVT in Morocco. Methods: Within the realm of a nation-wide study on canine and feline tumors in Morocco between September 2020 and March 2023, dogs with histologically diagnosed TVT were identified and data on epidemiologic, clinical as well as cytologic, and histologic features were compiled and analyzed. Results: A total of 64 cases of canine TVT were diagnosed. 52 dogs were cross-breed (81.2%) while 4 Siberian Huskies (6.2%) and 3 German shepherds (4.7%) were the most affected pure-breed dogs. The median age of dogs at diagnosis was 3 years (range, 1-10years) and male gender was more common (male:female ratio; 1.3:1). Tumor was located exclusively in the genital area in 58 cases (90.6%), whereas 6 dogs (9.4%) had an atypical occurrence of TVT with locations including skin and nasal cavity. Cytology allowed for an early diagnosis in 2 cases. Histology revealed no differences between the genital and extragenital forms. Immunohistochemistry was necessary in 4 cases and revealed positive staining for vimentin and Alpha-1-antitrypsin, negative marking for CD3, CD20, and AE1/AE3, and low cytoplasmic labeling for lysozyme. Conclusion: CTVT is a widely distributed neoplasm in Morocco, mostly showing presence in young, cross-breed, and oftentimes stray dogs. An adequate understanding of this tumor's epidemiological features is necessary for its management and eradication.

Transmissible cancers, the genomes that do not melt down.

Evolutionary theory predicts that the accumulation of deleterious mutations in asexually reproducing organisms should lead to genomic decay. Clonally reproducing cell lines, i.e., transmissible cancers, when cells are transmitted as allografts/xenografts, break these rules and survive for centuries and millennia. The currently known 11 transmissible cancer lineages occur in dogs (canine venereal tumour disease), in Tasmanian devils (devil facial tumor diseases, DFT1 and DFT2), and in bivalves (bivalve transmissible neoplasia). Despite the mutation loads of these cell lines being much higher than observed in human cancers, they have not been eliminated in space and time. Here, we provide potential explanations for how these fascinating cell lines may have overcome the fitness decline due to the progressive accumulation of deleterious mutations and propose that the high mutation load may carry an indirect positive fitness outcome. We offer ideas on how these host-pathogen systems could be used to answer outstanding questions in evolutionary biology. The recent studies on the evolution of these clonal pathogens reveal key mechanistic insight into transmissible cancer genomes, information that is essential for future studies investigating how these contagious cancer cell lines can repeatedly evade immune recognition, evolve, and survive in the landscape of highly diverse hosts.

Immunohistochemical expression of vimentin, E-cadherin, and CD45 in natural cases of canine cutaneous round tumors.

Round cell tumors are common cutaneous lesions in dogs, with increased occurrence percentages among different skin tumors. This study aimed to investigate the frequency as well as gross and pathological characteristics of round cell tumors in natural cases of tumorous dogs in relation to breed, sex, and age. Moreover, it aimed to evaluate the immunohistochemical expression of a panel of immunohistochemical stains, including vimentin, E-cadherin, and cluster of differentiation (CD45) as an adjunct technique for the differential diagnosis of cutaneous round cell neoplasm. Data were collected from 64 dogs of both sexes (36 females and 28 males), various breeds, and different ages (8 months to 7 years). The histopathological nature of neoplastic growth was reported, and neoplasm prevalence was classified using age, sex, breed, and site on the body. We observed 48 cases of transmissible venereal tumors, 12 cutaneous histiocytomas, and 4 histiocytic sarcoma. Immunohistochemical characterization revealed an intense positive immunoreactivity for vimentin in transmissible venereal tumor cells and moderate positive immunoreactivity for E-cadherin and CD45 in cutaneous histiocytoma and histiocytic sarcoma cells. In conclusion, the canine transmissible venereal tumor was the most frequent form of round cell tumor; thus, a definitive cutaneous neoplasm diagnosis should be based on histopathological morphology and immunohistochemical findings.

Effect of vincristine on intraocular pressure and tear fluid oxidative stress biomarkers in canine transmissible venereal tumor.

BACKGROUND: The ocular side effects of cancer chemotherapeutic drugs are relatively uncommon. Nonetheless, the ocular system has a potentially high sensitivity to toxic substances. This study proposed a framework to assess the effect of vincristine chemotherapy on intraocular pressure, tear protein, and oxidative stress in canines with transmissible venereal tumor (TVT). METHODS: The study group comprised 10 dogs with TVT, whose diagnosis was based on cytology, and all dogs were treated with vincristine for 4 weeks. Each animal was given a complete ophthalmic examination, followed by a standard Schirmer tear test. Before and 20 min after administering vincristine, intraocular pressure (IOP) was measured in the eyes with a noncontact tonometer. At any of the times mentioned, tear samples were collected using the Schirmer test procedure and were subjected to protein analysis-oxidative stress index (OSI), total antioxidant capacity (TAC), total oxidant status (TOS), nitric oxide (NO), and malondialdehyde (MDA) were determined, and standard statistical analysis was applied. RESULTS: No significant differences were found in protein in tears, but mean Pre and Postinjection IOP revealed a significant decrease in the eyes each week. Also, results indicated significant differences in oxidative stress markers: increased OSI, NO, and MDA, and reduced TAC. CONCLUSION: The importance of an increase in oxidative stress levels in the tears of vincristine-treated patients should be taken seriously, as it appears to play a role in the pathogenesis of eye disease. Therefore, during the treatment weeks prior to prescribing vincristine, eye diseases should be evaluated and considered.

Comparison of serum 25(OH) vitamin D, parathormone and immunity marker concentrations between dogs with transmissible venereal tumour and healthy dogs.

BACKGROUND: 1,25-Dihydroxyvitamin D (1,25(OH)2 D) is vital in the homeostasis of calcium and bone health as well as in the prevention of many disorders such as neoplasms. Epidemiological data show that low concentrations of both 1,25(OH)2 D and its precursor 25(OH) vitamin D (25(OH)D) are associated with an increased risk of a variety of human tumours. OBJECTIVES: To investigate 25(OH)D, parathormone (PTH) and immunity marker concentrations in dogs with transmissible venereal tumour (TVT). METHODS: 25(OH)D, PTH and various biochemical and immunity markers were evaluated in dogs with TVT (n = 26) and in healthy (n = 30) dogs. RESULTS: 25(OH)D concentrations were significantly lower in dogs with TVT in comparison with healthy dogs. In contrast, PTH, immunoglobulin G and interleukin (IL)-9 concentrations were higher in the dogs with TVT. Other variables, including IL-10, interferon γ, calcium and inorganic phosphate, were not statistically different between the two groups. CONCLUSIONS: Decreased serum 25(OH)D concentration may be a risk factor for the development of canine TVT; however, cause-and-effect remains incompletely understood. Further studies are required to elucidate the exact role of 25(OH)D in canine TVT and whether vitamin D supplementation may be useful prophylactically or as an adjunct to chemotherapy.

Vincristine-associated total antioxidant and oxidant status of ovaries and in vitro nuclear oocyte maturation in dogs with canine transmissible venereal tumor.

The aim of this study is to evaluate the effects of scheduled vincristine sulfate therapy on canine oocyte quality and nuclear oocyte maturation, associated with total antioxidant and oxidant status of ovaries and Anti-Müllerian Hormone (AMH) concentrations in dogs with Canine Transmissible Venereal Tumor (CTVT). Six bitches suffering from CTVT and six healthy bitches were included in the study. Hemogram was carried out weekly. AMH measurements and ovariohysterectomy operations were performed after the termination of vincristine sulfate therapies. Tissue samples from ovaries were utilized for Malondialdehyde (MDA), reduced Glutathione (GSH), Superoxide Dismutase (SOD), Total Anti-oxidative Status (TAS), Total Oxidative Status (TOS) measurements, and Oxidative Stress Index (OSI) was calculated. Collected oocytes were evaluated for meiotic competence, after In Vitro Maturation (IVM) and parthenogenetic activation. No difference between the two groups was observed in hematologic parameters (P > 0.05). Meiotic stages of Germinal Vesicle Break Down (GVBD), Metaphase I (MI), and Metaphase II (MII) were significantly different between groups (P < 0.05). The number of oocytes reaching MII and meiotic resumption was lower in the CTVT group. Furthermore, AMH concentrations, oxidant parameters (OSI, TOS, and MDA), and antioxidant parameters (GSH, SOD, and TAS) were also statistically different between groups (P < 0.05). The results of this study show that vincristine sulfate application in the treatment of CTVT could alter oxidant/antioxidant status in ovaries. Apart from these, oocyte quality and IVM rates seem to decline related to gonadotoxicity. Moreover, AMH could be an important marker in the evaluation of oocyte qualities in bitches, as it is in women.

Transmission of canine transmissible venereal tumour between two dogs in the UK.

Canine transmissible venereal tumour (CTVT) is a contagious cancer spread by transfer of living cancer cells. Occasional cases are observed in the UK in dogs imported from endemic regions. Here, we report a case of imported canine transmissible venereal tumour that was transmitted to a second dog within the UK. Transmission of genital canine transmissible venereal tumour occurred despite neutered status of the second dog. The aggressive course of disease in both cases, which included metastasis, resistance to therapeutic interventions and ultimate euthanasia of both dogs, is described. The diagnosis of canine transmissible venereal tumour was made using a combination of cytology, histology, immunohistochemistry and PCR to detect the LINE-MYC rearrangement. Practitioners unfamiliar with canine transmissible venereal tumour are reminded of this disease of concern, particularly when imported dogs are placed in multi-dog households, irrespective of neuter status.

Canine transmissible venereal tumor - From general to molecular characteristics: A review.

Cancer is a group of complex diseases resulting from the accumulation of genetic and epigenetic changes affecting control and activity of several genes, especially those involved in cell differentiation and growth processes, leading to an abnormal proliferation. When the disease reaches an advanced stage, cancer can lead to metastasis in other organs. Interestingly, recent studies have shown that some types of cancer spread not only through the body, but also can be transmitted among individuals. Therefore, these cancers are known as transmissible tumors. Among the three types of transmissible tumors that occur in nature, the canine transmissible venereal tumor (CTVT) is known as the oldest cancer in the world, since it was originated from a single individual 11 000 years ago. The disease has a worldwide distribution, and its occurrence has been documented since 1810. The CTVT presents three types of cytomorphological classification: lymphocytoid type, mixed type, and plasmacytoid type, the latter being chemoresistant due to overexpression of the ABCB1 gene, and consequently increase of the P-glycoprotein. More knowledge about the epidemiology and evolution of CTVT may help to elucidate the pathway and form of the global spread of the disease.

Immunophenotypic and molecular profile of cancer stem-cell markers in ex vivo canine transmissible venereal tumour (CTVT).

BACKGROUND: Several studies have attempted to characterise the origin of canine transmissible venereal tumour (CTVT). However, the participation of cancer stem cells (CSC) has not been reported OBJECTIVES: Herein we describe the expression patterns of CSC markers CD44, CD34, CD90 and CD133 in CTVT METHODS: Thirty-eight samples were selected and assessed through flow cytometry and immunohistochemistry RESULTS AND CONCLUSIONS: Twenty-two tumours were classified as plasmacytoid and 16 as mixed. Almost all tumours showed high CD44 and low CD34 levels. CD133 and CD90 expression varied among tumours. Cytological groups did not differ in the proportion of CSC markers. Our results suggest that CSC subpopulations might participate in CTVT.

Sex disparity in oronasal presentations of canine transmissible venereal tumour.

BACKGROUND: The canine transmissible venereal tumour (CTVT) is a contagious cancer spread by the direct transfer of living cancer cells. CTVT usually spreads during mating, manifesting as genital tumours. However, oronasal CTVT is also occasionally observed, and presumably arises through oronasal contact with genital CTVT tumours during sniffing and licking. METHODS: Given that sniffing and licking transmission behaviours may differ between sexes, we investigated whether oronasal CTVT shows sex disparity. RESULTS: Twenty-seven of 32 (84%) primary oronasal tumours in a CTVT tumour database occurred in males. In addition, 53 of 65 (82%) primary oronasal CTVT tumours reported in the published literature involved male hosts. These findings suggest that male dogs are at four to five times greater risk of developing primary oronasal CTVT than females. This disparity may be due to sex differences in licking and sniffing activity, perhaps also influenced by sex differences in CTVT accessibility for these behaviours. CONCLUSION: Although oronasal CTVT is rare, it should be considered as a possible diagnosis for oronasal tumours, particularly in male dogs.

Cell-mediated immunity and expression of MHC class I and class II molecules in dogs naturally infected by canine transmissible venereal tumor: Is there complete spontaneous regression outside the experimental CTVT?

The canine transmissible venereal tumor (CTVT) is a transplantable cancer with the ability evade the immune system, despite strict immune surveillance of the host; in this context, the relationship between inflammatory infiltrate and CTVT prognosis is not entirely understood. Natural canine transmissible venereal tumors of 22 dogs were evaluated for tumor/host interaction through clinical and epidemiological data, cyto-histopathological and cytogenetic findings and, mainly, cell-mediated immune response. We performed analysis on dogs with naturally acquired disease to provide information from the study of CTVT biology in its natural course, as the clinical evolution of the natural tumor in the host is not yet as well known as in the laboratory. Populations for T cell labeling (CD3+ CD4+ CD8+), B cells, NK cells, and macrophages were analyzed by flow cytometry in blood and tumor samples and expressions of MHC class I and class II molecules were quantified by immunohistochemistry and compared mainly between the phases of progression and regression in the natural CTVT. Dogs were also treated with vincristine sulfate and evaluated for chemotherapeutic response. Chemotherapy was effective in 88% of cases and there was no recurrence of the disease 12 months after the cure. Tumor cells displayed a numerical chromosomal variation between 54 and 72, not correlating with the host genotype. Although a greater expression of MHC molecules [18.6 ± 5.8% class I (P < 0.004) and 38.5 ± 6.5% class II (P < 0.003)] was observed in the regression phase, no significant effect was observed between the clinical phase of the tumor and cellular immune response in the analysis by flow cytometry (P > 0.05). We also found no correlation between cytological subtype of the tumor (plasmacytoid, lymphocytoid and mixed) and cellular immune response, suggesting that there is no difference in tumor immunogenicity. Here, we found no immunological evidence to support the theory of the immune-induced complete spontaneous regression in CTVT.

A retrospective study of canine transmissible venereal tumour in Grenada, West Indies.

BACKGROUND: Canine transmissible venereal tumour (CTVT) is a naturally occurring neoplasia affecting dogs worldwide. Previous CTVT studies in Grenada were limited to case records of dogs with neoplastic conditions at a veterinary diagnostic laboratory. OBJECTIVES: The present retrospective study aimed to determine the occurrence and risk factors of CTVT in a wider population of owned dogs presented to a university-affiliated veterinary hospital between 2008 and 2018. METHODS: Data on the age, breed, gender, and gonadectomy status were retrieved from an electronic database and analyzed using logistic regression. RESULTS: Of the 7180 dogs presented during the period, 102 dogs (1.4%) were diagnosed with CTVT. A higher predisposition was observed in Grenadian pothounds (odds ratio [OR] = 22.8, 95% confidence interval [CI] 10.3-50.4; p < 0.001) and mixed-breed dogs (OR = 9.2, 95% CI 4.1-20.7; p < 0.001) in comparison to the purebreds. Neutered dogs (OR = 2.2, 95% CI 1.4-3.3; p < 0.001) were at an increased risk of CTVT than intact dogs. Age and gender were not identified as significant risk factors. CONCLUSIONS: The percentage of dogs with CTVT in this study represents a crude estimate of the CTVT prevalence in the owned dog population in Grenada. Further studies including both owned and free-roaming dogs are required for a more accurate estimation of the CTVT prevalence in the region. Our results indicate that breed and gonadectomy status are significant risk factors for the occurrence of CTVT in Grenada.

Relationship between plasma cell-free DNA changes and lysyl oxidase during the treatment and prognosis of canine transmissible venereal tumors.

BACKGROUND: Transmissible venereal tumors (TVT) are a wide range of canine tumors for which there are no effective markers to monitor the therapeutic response in real-time. Circulating biomarkers can be valuable in early cancer diagnosis and prognosis. Accordingly, this study aimed to investigate the significance of the cell-free DNA (cfDNA) and cfDNA integrity index to monitor the response of TVTs to vincristine and compare them with lysyl oxidase activity. Plasma and sera were collected from fifteen male dogs within four weeks before drug administration. The analytical method was mainly based on the quantitative polymerase chain reaction (qPCR) technique for short and long cfDNAs and lysyl oxidase activity was measured in serum. RESULTS: The results of the cfDNA integrity index showed a significant (p < 0.05) difference in the baseline concentration compared to the second and third weeks (with cut-off values of 1.118 and 93.33% specificity). The cfDNA integrity index increased over time due to the reduction of short cfDNAs in the first week after treatment. Lysyl oxidase activity increased during the fourth week (p < 0.001), but there were no significant differences in the other weeks compared to the baseline. The ROC analysis of lysyl oxidase revealed high sensitivity (100%) and specificity (90%) on the second and third weeks compared to the baseline. Multivariate analysis between cfDNA integrity index and lysyl oxidase showed significant correlation (p < 0.05) only in baseline results. CONCLUSIONS: Overall, short cfDNA, the cfDNA integrity index, and lysyl oxidase activity can be proposed as diagnostic biomarkers and putative prognostic candidates in TVT patients. These biomarkers can be combined with cytology to quickly diagnose TVT.

Vincristine sulfate treatment influence on kidney function of female dogs with transmissible venereal tumor / Influência do tratamento com sulfato de vincristina na função renal de cadela com tumor transmissível venéreo

Chemotherapy agents have some undesirable and non-selective cytostatic effects. Considering that kidneys are vulnerable to drug-induced toxicity, this study evaluated renal injury caused by vincristine sulfate (VS) in 12 female dogs diagnosed with transmissible venereal tumor (TVT). The animals were treated with VS (0.025 mg/kg IV) every 7 days for 4 weeks. During treatment, the animals were subjected to clinical examination, blood count, serum measurement of symmetric dimethylarginine (SDMA), blood urea nitrogen (BUN), creatinine, alanine aminotransferase, and alkaline phosphatase. In addition, urinalysis and urinary gamma-glutamyl transferase (GGT) measurements were performed. All parameters were determined three times: before beginning the treatment (T0), after 14 days (T1), and after 28 days (T2). During the study period, there were no changes in serum urea or creatinine levels, urine specific gravity, or persistent proteinuria. Furthermore, urinary GGT measurement did not indicate tubular lesions, and consistent elevation of SDMA was found in only one patient above the reference range. The results showed that weekly therapy with VS as a single agent for 28 days does not induce renal injury in most cases.(AU)

Os agentes quimioterápicos possuem efeitos citostáticos indesejáveis e não seletivos. Considerando a vulnerabilidade renal à toxicidade induzida por drogas, este estudo avaliou a lesão renal causada pelo sulfato de vincristina (VS) em 12 cadelas com diagnóstico de tumor venéreo transmissível (TVT). Os animais foram tratados com VS (0,025 mg / kg IV) a cada sete dias, durante quatro semanas. No transcurso do tratamento, os animais foram submetidos a exame clínico, hemograma, dosagem sérica de dimetilarginina simétrica (SDMA), nitrogênio ureico sanguíneo (BUN), creatinina, alanina aminotransferase e fosfatase alcalina. Além disso, foram realizadas análises de urina e medições de gama-glutamil transferase (GGT) urinária. Todos os parâmetros foram mensurados em três tempos, antes do início do tratamento (T0), aos 14 dias (T1) e aos 28 dias (T2). Durante o período do estudo, não houve alterações nas concentrações de ureia ou creatinina séricas, na gravidade específica da urina ou proteinúria persistente. Além disso, a medição de GGT urinária não indicou lesões tubulares, e elevação consistente de SDMA foi encontrada em apenas um paciente acima do intervalo de referência. Os resultados mostraram que a terapia semanal com VS como agente único por 28 dias não induz lesão renal na maioria dos casos.(AU)

Canine transmissible venereal tumour established in immunodeficient mice reprograms the gene expression profiles associated with a favourable tumour microenvironment to enable cancer malignancy.

BACKGROUND: Canine transmissible venereal tumours (CTVTs) can cross the major histocompatibility complex barrier to spread among dogs. In addition to the transmissibility within canids, CTVTs are also known as a suitable model for investigating the tumour-host immunity interaction because dogs live with humans and experience the same environmental risk factors for tumourigenesis. Moreover, outbred dogs are more appropriate than inbred mice models for simulating the diversity of human cancer development. This study built a new model of CTVTs, known as MCTVTs, to further probe the shaping effects of immune stress on tumour development. For xenotransplantation, CTVTs were first injected and developed in immunodeficient mice (NOD.CB17-Prkdcscid/NcrCrl), defined as XCTVTs. The XCTVTs harvested from NOD/SCID mice were then inoculated and grown in beagles and named mouse xenotransplantation of CTVTs (MCTVTs). RESULTS: After the inoculation of CTVTs and MCTVTs into immune-competent beagle dogs separately, MCTVTs grew faster and metastasized more frequently than CTVTs did. Gene expression profiles in CTVTs and MCTVTs were analysed by cDNA microarray to reveal that MCTVTs expressed many tumour-promoting genes involved in chronic inflammation, chemotaxis, extracellular space modification, NF-kappa B pathways, and focal adhesion. Furthermore, several well-known tumour-associated biomarkers which could predict tumour progression were overexpressed in MCTVTs. CONCLUSIONS: This study demonstrated that defective host immunity can result in gene instability and enable transcriptome reprogramming within tumour cells. Fast tumour growth in beagle dogs and overexpression of tumour-associated biomarkers were found in a CTVT strain previously established in immunodeficient mice. In addition, dysregulated interaction of chronic inflammation, chemotaxis, and extracellular space modification were revealed to imply the possibly exacerbating mechanisms in the microenvironments of these tumours. In summary, this study offers a potential method to facilitate tumour progression and provide a niche for discovering tumour-associated biomarkers in cancer research.

Epidemiological study of canine transmissible venereal tumor (CTVT) in Brazil, 2000-2020.

Canine transmissible venereal tumor (CTVT) is a contagious neoplasm, mainly transmitted through coitus. This round cell mesenchymal tumor is common in Brazil, often located in the genitalia although extragenital presentations may also occur, such as cutaneous, oral, and nasal forms. The objective of this study was to perform an epidemiological analysis of CTVT from published data in the recent academic literature to systematically demonstrate the distribution of CTVT in Brazil, identify the frequency of this neoplasm and its main diagnostic tests, and characterize its main clinical manifestations in Brazil. For such purpose, it was analyzed the scientific publications with cases of CTVT in Brazil, in English or Portuguese, published between 2000-2020. The CTVT was identified in 19 Brazilian states plus the Federal District, totaling 3,622 cases across the national territory, with the largest number of cases recorded in the Southeast region. The cytological exam was the most used for the diagnosis of CTVT (89.2 %), followed by histopathological (37.8 %) and immunohistochemistry (13.5 %)1 . Predominant epidemiological aspects of CTVT identified in the study were: Mixed breed dogs (75.2 %), females (62.5 %), in adulthood (between 2 and 7 years) and dogs with free extra outdoor access (91.1 %). Genital presentation was the most frequent in the literature (86 %), followed by cutaneous (21.8 %), nasal (10 %), oral and lymph nodes presentations (10-5 %) and less frequent manifestations as ocular and anal/perianal (< 5 %). CTVT is a neoplasm widely distributed in Brazil, highly frequent and with several forms of clinical presentation, which can be underdiagnosed if there is no adequate knowledge of this tumor and its epidemiological characteristics. The extragenital manifestations of the neoplasm need further studies for its better characterization and more precise definition of its frequencies.