Veterinary Oncology / Immuno-Oncology

A brief introduction to Veterinary Oncology / Immuno-Oncology:

(Also see our TILs manuscript at: Cancers | Free Full-Text | Comparative Evaluation of Tumor-Infiltrating Lymphocytes in Companion Animals: Immuno-Oncology as a Relevant Translational Model for Cancer Therapy (

Mice vs domestic species (dogs in particular)

  • Natural occurring animal models of disease offer unique and valuable aspects with analogous behavioural tumoural characteristics and responses to human counterparts
  • Domestic species = immunologically outbred species
  • Similar body sizes and metabolic pathways where effects of drug activity and toxicity can be more thoroughly studied compared to mice. Domestic species also share the same environment of their human companions, and are therefore exposed to many of the same allergens, food antigens, and environmental chemicals
  • Shorter lifespan overall when compared to humans allows for more rapid treatment response evaluation and observation of disease progression
  • Canine immune system is much more primed, mounts immune responses in primary and metastatic disease and can eventually develop antitumoral immunity compared to mouse models (implanted or induced tumour models)


Immune Cells and Immune Responses: Dog Vs Human 

  • Same CD4 and CD8 T cells
  • Gamma delta T Cells
  • T-regs (CD4+FoxP3+)
  • The same repertoire of markers are present on the majority of the canine vs. human immune system

Immune checkpoint inhibitors characterized in Dogs

  • PD-1, OX40, CD28, TIGIT, TIM-3, and Lag3
  • APCs with MHCII, CD40, CD80, CD86, PD-L1 expression
  • PD-1 as antibody; phase I trial completion in dogs with a variety of different cancers
  • Other canine checkpoint targeted antibodies against PD-L1 and OX40 antibodies
  • Therapeutics are on their way
    • Merck has a canine validated Anti-PD1 antibody due for 2023


  • Preponderance of mast cells compared to humans; mucosal sites/ mast cell tumors more common in dogs than in humans.
  • Dogs also develop malignancies of cells of the DC and macrophage lineage (histiocytoma, histiocytic sarcoma) at a much higher rate than in humans (e.g., Langerhans histiocytosis)
    • Though these provide unique opportunities to translate therapeutics for these diseases back to humans
  • Humane euthanasia in veterinary medicine may impact translatability of biomarker evaluation


Current Immune-Based Therapeutics in Veterinary Oncology:

Cancer vaccines

  • Canine osteosarcoma Listeria-vectored vaccine targeting HER2/neu can effectively prevent tumor metastases, and control the growth of macroscopic metastases
  • Plasmid-DNA based tumor vaccine targeting the TERT antigen, which has been evaluated in dogs with lymphoma in combination with CHOP chemotherapy
  • GD3 antigen in canine melanoma studies
  • Melanoma vaccine commercially available (xenogeneic plasmid vaccine against tyrosinase)
  • Oncolytic herpesvirus vaccine in canine glioma


Adoptive cell therapy (ACT) and CAR T cells

  • Still early overall but has been documented in:
    • Lymphoma
    • Osteosarcoma
      • Adoptive transfer of non-specifically activated T-cells + IL-15 activated NK cells led to improved survival

Monoclonal Antibodies

  • Anti-CD20 for canine lymphoma
  • Caninized immune-checkpoint inhibitors are in development
    • Cross-overlap of active binding regions have been documented with human immune checkpoint inhibitors


Cytokines + Other

  • Validated research tools for cytokine analysis in dogs
    • Lymphoma
    • Urothelial carcinoma (MIUC)
  • Proven similarities in humans as biomarkers or indicative of TME behaviour
  • IL-12 nanoparticles (soft tissue sarcoma)
  • Inhalant IL-15 for pulmonary metastases
  • IL-2 for feline injection site sarcomas
  • Metronomic chemotherapy resultant in T-cell depletion
  • Palladia (Toceranib Phosphate) and other TKIs used in veterinary medicine



Veterinary TILs WG Subheading Proposal

Companion Animal Subheading

  • Introduction / Report MDPI Cancers Paper above
    • Review paper as a main heading
      • Table 1 from our review paper would be a good summary and easy to read on the website
    • List histologic grading schemes currently validated in veterinary oncology in comparison to human
  • Comparative Image Bank
    • Histopathology with side-by-side tumour images and TILs [where available] for most common tumours or those with high comparative relevance (H&E)
      • Lung Carcinoma
      • Gastric Carcinoma
      • Prostatic Carcinoma
      • MIUC
      • Lymphoma
      • Osteosarcoma
      • Melanoma
      • Myeloma
        • Eventually an additional set of similar image repository with IHC & PD-L1 markers (or other immune checkpoint markers)
      • Additional large/farm animal tumour images
      • Cytologic sample images of the above tumour types as well
    • Comparative / Translational AI Toolset
      • Highlight need for AI-based tools and standardization in veterinary oncology/pathology
      • List of current AI / pathomic literature present in companion animals
      • Future plan: standardization of a high-resolution TILs maps on whole slide images and foundation of a platform similar to TIGER (tumour infiltrating lymphocytes in breast cancer) for common tumours in domestic species with a scope of incorporating other species (farm and wildlife).
        • Utilize ML platform proposed by RS in dogs/cats in a validation study
        • AI and ML platforms are in still early in veterinary medicine and there are no publications on pathomic evaluation of TILs, spatial relationships, or as biomarker development – there is certainly a need here that our group could lead
      • Guidelines in development
        • Continuously updated drafts of TILs assessment guidelines available for public comment
      • Opportunities in veterinary oncology
        • Items promoting missing data, or missing information veterinary immuno-oncology
          • List with current state of immunotherapies in veterinary oncology
            • Melanoma vaccine
            • Anti-PD-L1 therapeutic (Merck; coming 2023)
            • Rituximab-like CD20 monoclonal antibody for Canine Lymphoma (retracted form market due to poor performance in clinical setting)
            • CAR-T & other adoptive T-cell therapeutics
            • Autologous cancer vaccines
            • **Need for Adoptive TIL therapies
            • Improved NK Cell detection
          • Collaboration Hub
            • A place for researchers / projects (validated by the group) to list projects in need of multidisciplinary collaboration as well as contact information
          • Regulatory Commentary
            • It is likely too early for TILs regulatory involvement in veterinary medicine
            • However, as interest grows, there will be an increasing need for our group to formulate a stance and assist regulatory bodies such as the FDA, Health Canada and others to ensure research groups are following the WGs guidelines


Initial WG Project Proposals:

  • Work on a sample Repository for each tumour type (with clinical history, follow up etc)- multiple tumour types with TIL evaluation using the TIL working group schema
  • While collating cases and characterizing TILs follow up data could further modify/update existing veterinary medicine tumour diagnostic schemes (a template of all current schemes will be uploaded and associated with all corresponding tumours)
  • Multimodal and multidimensional immune profiling of tumours; spatial organization of the tumour microenvironment using cyclic immunofluorescence microscopy (CYCIF) and either conventional wide field microscopy or 3D optical sectioning and CyTOF and scRNAseq analyses for deep immune profiling of the tumour microenvironment.
    • Include transcriptional profiling (Nanostring Technology) of selected microregions and correlation with histopathology of the tumour
    • Spatial segmentation with GeoMX Digital Spatial profiler
    • Application of AI toolset to these analyses for biomarker development
  • Work towards clinical toolset / application as the group’s work and literature matures (prognostic scoring)

Possible Grant Funding for projects within the WG:

  • American Kennel Club Canine Health Foundation Grants (Canada & US)
  • Morris Animal Foundation (Canada & US)
  • CIHR Grants (Canada)
  • OICR (Ontario, Canada)
  • Terry Fox Foundation (Canada)
  • Ontario Veterinary College Pet Trust (Internal, Ontario Veterinary College)
  • Animal Care Trust (Internal, The Royal Veterinary College)
  • British Small Animal Veterinary Association (BSAVA, UK)
  • Biotechnology and Biological Sciences Research Council (BBSRC, UK)
  • The Animal Welfare Foundation (UK)



References for Interest:

  1. Chambers MR, Foote JB, Bentley RT, Botta D, Crossman DK, Della Manna DL, Estevez-Ordonez D, Koehler JW, Langford CP, Miller MA, Markert JM, Olivier AK, Omar NB, Platt SR, Rissi DR, Shores A, Sorjonen DC, Yang ES, Yanke AB, Gillespie GY. Evaluation of immunologic parameters in canine glioma patients treated with an oncolytic herpes virus. J Transl Genet Genom. 2021;5(4):423-442. doi: 10.20517/jtgg.2021.31. Epub 2021 Dec 5. PMID: 35342877; PMCID: PMC8955901.
  2. Chen HW, Small GW, Motsinger-Reif A, Suter SE, Richards KL. VH1-44 gene usage defines a subset of canine B-cell lymphomas associated with better patient survival. Vet Immunol Immunopathol. (2014) 157:125–30. doi: 10.1016/j.vetimm.2013.10.020
  3. Canter RJ, Grossenbacher SK, Foltz JA, Sturgill IR, Park JS, Luna JI, et al. Radiotherapy enhances natural killer cell cytotoxicity and localization in pre-clinical canine sarcomas and first-in-dog clinical trial. J Immunother Cancer. (2017) 5:98. doi: 10.1186/s40425-017-0305-7
  4. Thamm DH, Kurzman ID, King I, Li Z, Sznol M, Dubielzig RR, et al. Systemic administration of an attenuated, tumor-targeting Salmonella typhimurium to dogs with spontaneous neoplasia: phase I evaluation. Clin Cancer Res. (2005) 11:4827–34. doi: 10.1158/1078-0432.CCR-04-2510
  5. Paoloni M, Mazcko C, Selting K, Lana S, Barber L, Phillips J, et al. Defining the pharmacodynamic profile and therapeutic index of NHS-IL12 immunocytokine in dogs with malignant melanoma. PLoS ONE. (2015) 10:e0129954. doi: 10.1371/journal.pone.0129954
  6. Kurzman ID, MacEwen EG, Rosenthal RC, Fox LE, Keller ET, Helfand SC, et al. Adjuvant therapy for osteosarcoma in dogs: results of randomized clinical trials using combined liposome-encapsulated muramyl tripeptide and cisplatin. Clin Cancer Res. (1995) 1:1595–601.
  7. Mason NJ, Gnanandarajah JS, Engiles JB, Gray F, Laughlin D, Gaurnier-Hausser A, et al. Immunotherapy with a HER2-targeting listeria induces HER2-specific immunity and demonstrates potential therapeutic effects in a phase I trial in canine osteosarcoma. Clin Cancer Res. (2016) 22:4380–90. doi: 10.1158/1078-0432.CCR-16-0088
  8. Peruzzi D, Gavazza A, Mesiti G, Lubas G, Scarselli E, Conforti A, et al. A vaccine targeting telomerase enhances survival of dogs affected by B-cell lymphoma. Mol Ther. (2010) 18:1559–67. doi: 10.1038/mt.2010.104
  9. Thalmensi J, Pliquet E, Liard C, Chamel G, Kreuz C, Bestetti T, et al. A DNA telomerase vaccine for canine cancer immunotherapy. Oncotarget. (2019) 10:3361–72. doi: 10.18632/oncotarget.26927
  10. Milner RJ, Salute M, Crawford C, Abbot JR, Farese J. The immune response to disialoganglioside GD3 vaccination in normal dogs: a melanoma surface antigen vaccine. Vet Immunol Immunopathol. (2006) 114:273–84. doi: 10.1016/j.vetimm.2006.08.012
  11. Panjwani MK, Smith JB, Schutsky K, Gnanandarajah J, O'Connor CM, Powell DJ Jr, et al. Feasibility and safety of RNA-transfected CD20-specific chimeric antigen receptor T cells in dogs with spontaneous B cell lymphoma. Mol Ther. (2016) 24:1602–14. doi: 10.1038/mt.2016.146
  12. Flesner BK, Wood GW, Gayheart-Walsten P, Sonderegger FL, Henry CJ, Tate DJ, Bechtel SM, Donnelly LL, Johnson GC, Kim DY, Wahaus TA, Bryan JN, Reyes N. Autologous cancer cell vaccination, adoptive T-cell transfer, and interleukin-2 administration results in long-term survival for companion dogs with osteosarcoma. J Vet Intern Med. 2020 Sep;34(5):2056-2067. doi: 10.1111/jvim.15852. Epub 2020 Jul 10. PMID: 32649801; PMCID: PMC7517513.
  13. Gareau A, Ripoll AZ, Suter SE. A Retrospective Analysis: Autologous Peripheral Blood Hematopoietic Stem Cell Transplant Combined With Adoptive T-Cell Therapy for the Treatment of High-Grade B-Cell Lymphoma in Ten Dogs. Front Vet Sci. 2021 Dec 7;8:787373. doi: 10.3389/fvets.2021.787373. PMID: 34950726; PMCID: PMC8688351.
  14. Mochel JP, Ekker SC, Johannes CM, Jergens AE, Allenspach K, Bourgois-Mochel A, Knouse M, Benzekry S, Wierson W, LeBlanc AK, Kenderian SS. CAR T Cell Immunotherapy in Human and Veterinary Oncology: Changing the Odds Against Hematological Malignancies. AAPS J. 2019 Apr 8;21(3):50. doi: 10.1208/s12248-019-0322-1. PMID: 30963322.
  15. Lenz JA, Assenmacher CA, Costa V, Louka K, Rau S, Keuler NS, Zhang PJ, Maki RG, Durham AC, Radaelli E, Atherton MJ. Increased tumor-infiltrating lymphocyte density is associated with favorable outcomes in a comparative study of canine histiocytic sarcoma. Cancer Immunol Immunother. 2022 Apr;71(4):807-818. doi: 10.1007/s00262-021-03033-z. Epub 2021 Aug 20. PMID: 34415404; PMCID: PMC8858331.
  16. Dhawan D, Hahn NM, Ramos-Vara JA, Knapp DW. Naturally-occurring canine invasive urothelial carcinoma harbors luminal and basal transcriptional subtypes found in human muscle invasive bladder cancer. PLoS Genet. 2018 Aug 8;14(8):e1007571. doi: 10.1371/journal.pgen.1007571. PMID: 30089113; PMCID: PMC6101404.
  17. Chambers MR, Foote JB, Bentley RT, Botta D, Crossman DK, Della Manna DL, Estevez-Ordonez D, Koehler JW, Langford CP, Miller MA, Markert JM, Olivier AK, Omar NB, Platt SR, Rissi DR, Shores A, Sorjonen DC, Yang ES, Yanke AB, Gillespie GY. Evaluation of immunologic parameters in canine glioma patients treated with an oncolytic herpes virus. J Transl Genet Genom. 2021;5(4):423-442. doi: 10.20517/jtgg.2021.31. Epub 2021 Dec 5. PMID: 35342877; PMCID: PMC8955901.