Pilot study: Understanding canine transmissible venereal tumor through its transcriptional profile.

Canine transmissible venereal tumor (CTVT) is transmitted through the implantation of tumor cells. CTVT was the first tumor described with contagious characteristics and remains one of the few tumors with this capability. This study aimed to map the transcriptomic profile of CTVT to elucidate the potential mechanisms through which this tumor implants and evades host immune surveillance. For this study, 11 dogs aged ≥ 2 years diagnosed with CTVT were selected. Tumor biopsies were performed, RNA was extracted and converted into complementary DNA, followed by RT-qPCR analysis. The transcriptomic profile of CTVT revealed a wide array of differentially expressed genes. However, only the most relevant genes from an oncological perspective were discussed. IL-8, CXCL13, NCAM1, RNASEL, COROA1, and CBLB demonstrated potential associations with immune system evasion and transmission via implantation. Therefore, studying these genes may contribute to the development of targeted therapies that prevent contagion and immune evasion.

de Sanctis Augusto P ，Dinau FC ，González-Zambrano CM ，Montoya-Flórez LM ，Araújo JP ，Rocha NS ... -  《-》

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.

do Prado Duzanski A ，Flórez LMM ，Fêo HB ，Romagnoli GG ，Kaneno R ，Rocha NS ... -  《-》

Effect of tumor infiltrating lymphocytes on the expression of MHC molecules in canine transmissible venereal tumor cells.

Hsiao YW ，Liao KW ，Hung SW ，Chu RM ... -  《VETERINARY IMMUNOLOGY AND IMMUNOPATHOLOGY》

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.

Pimentel PAB ，Oliveira CSF ，Horta RS 《-》

Extensive conservation of genomic imbalances in canine transmissible venereal tumors (CTVT) detected by microarray-based CGH analysis.

Thomas R ，Rebbeck C ，Leroi AM ，Burt A ，Breen M ... -  《-》