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Abstract Background Knowledge of the prevalence of thromboemboli and the associated hemostatic status in dogs with carcinoma or sarcoma is unknown and might allow earlier intervention. Objectives Estimate prevalence of thromboemboli and their association with hemostatic changes in dogs with carcinomas or sarcomas; estimate predictive values of hemostatic variables for thromboembolic disease in tumor‐bearing dogs. Animals Thirty‐two dogs with sarcoma, 30 with carcinoma, 20 healthy age‐controlled dogs. Methods Prospective cross‐sectional study. A hemostasis panel (platelet concentration, thromboelastography, fibrinogen and D‐dimer concentration, factor X, VII and antithrombin activity) was performed in all dogs. Tumor‐bearing dogs underwent complete post mortem and histopathological evaluation. Comparisons between healthy dogs and tumor‐bearing dogs with and without intracavitary hemorrhage; and tumor‐bearing dogs with and without microthrombi were analyzed. Results Thromboembolic disease was identified in 32/62 (52%, 95% CI: 39%‐65%) tumor‐bearing dogs. Microthrombi were identified in 31/62 (50%, 95% CI: 37%‐63%) dogs, 21/31 (68%, 95% CI: 49%‐83%) had exclusively intra‐tumoral microthrombi, 10/31 (32%, 95% CI: 17%‐51%) had distant microthrombi. Macrothrombi were identified in 3 tumor‐bearing dogs. Hemostatic changes potentially consistent with overt and non‐overt disseminated intravascular coagulation were identified in some tumor‐bearing dogs. D‐dimer concentrations were significantly higher (P = .02) and platelet concentration significantly lower (P = .03) in tumor‐bearing dogs with microthrombi compared to tumor‐bearing dogs without microthrombi. D‐dimer concentration above 500 ng/mL was 80% sensitive and 41% specific for the prediction of microthrombi presence. Conclusion The high microthrombi prevalence and concomitant hemostatic dysfunction in dogs with carcinomas or sarcomas has not previously been reported, though the clinical importance is unknown. Increased D‐dimer concentration might increase suspicion of microthrombi.

Abstract Background In humans, muscle-invasive bladder cancer (MIBC) is highly aggressive and associated with a poor prognosis. With a high mutation load and large number of altered genes, strategies to delineate key driver events are necessary. Dogs and cats develop urothelial carcinoma (UC) with histological and clinical similarities to human MIBC. Cattle that graze on bracken fern also develop UC, associated with exposure to the carcinogen ptaquiloside. These species may represent relevant animal models of spontaneous and carcinogen-induced UC that can provide insight into human MIBC. Results Whole-exome sequencing of domestic canine (n = 87) and feline (n = 23) UC, and comparative analysis with human MIBC reveals a lower mutation rate in animal cases and the absence of APOBEC mutational signatures. A convergence of driver genes (ARID1A, KDM6A, TP53, FAT1, and NRAS) is discovered, along with common focally amplified and deleted genes involved in regulation of the cell cycle and chromatin remodelling. We identify mismatch repair deficiency in a subset of canine and feline UCs with biallelic inactivation of MSH2. Bovine UC (n = 8) is distinctly different; we identify novel mutational signatures which are recapitulated in vitro in human urinary bladder UC cells treated with bracken fern extracts or purified ptaquiloside. Conclusion Canine and feline urinary bladder UC represent relevant models of MIBC in humans, and cross-species analysis can identify evolutionarily conserved driver genes. We characterize mutational signatures in bovine UC associated with bracken fern and ptaquiloside exposure, a human-linked cancer exposure. Our work demonstrates the relevance of cross-species comparative analysis in understanding both human and animal UC.

Critical appraisal of the available literature for the treatment of canine oral malignant melanoma (OMM) is lacking. This critical review aimed to evaluate the current literature and provide treatment recommendations and possible suggestions for future canine OMM research. PubMed, Web of Science and Google Scholar were searched in June 2021, for terms relevant to treatment of OMM. Inclusion and exclusion criteria were applied and information on clinical response and outcome extracted. Eighty-one studies were included. The overall level of evidence supporting the various canine OMM treatment options was low. The majority of studies included confounding treatment modalities and lacked randomization, control groups and consistency in reporting clinical response and outcomes. Within these limitations, surgery remains the mainstay of therapy. Adjunctive radiotherapy provided good local control and improved median survival times (MST), chemotherapy did not offer survival benefit beyond that of surgery, while electrochemotherapy may offer a potential alternative to radiotherapy. Immunotherapy holds the most promise in extending MST in the surgical adjunctive setting, in particular the combination of gene therapy and autologous vaccination. Prospective, randomized, double-blinded clinical trials, with a lack of confounding factors and reporting based on established guidelines would allow comparison and recommendations for the treatment of canine OMM.