Canine extramedullary plasma cell tumors (EMPs) most commonly arise in the skin, oral cavity, rectum, and colon. This retrospective study describes the histopathological and immunohistochemical characteristics and associated clinical signs and outcomes of laryngeal and tracheal EMPs in dogs. Five tracheal and 5 laryngeal EMPs were diagnosed at the Penn Vet Diagnostic Laboratory. Clinical information was obtained via submission forms and follow-up questionnaires. All dogs were male (9 castrated), 7 to 15 years old, and of different breeds. Neoplasms were composed of well-differentiated (n = 6) or moderately differentiated (n = 4) neoplastic plasma cells arranged in sheets, cords, and packets. All neoplasms labeled positively for MUM-1, negatively for PAX5, and were variably CD20- and CD79b-positive. There was no recurrence or disease progression 2 months to 7 years post biopsy in 6/9 cases. Results suggest that surgical resection can result in positive outcomes. Further studies are needed to identify factors leading to progression of this disease.

Nasal biopsies from 21 dogs diagnosed with chondro-osseous respiratory epithelial adenomatoid hamartomas or respiratory epithelial adenomatoid hamartomas were reviewed. Associated lesions included angiomatous tissue (4/21), seromucinous gland proliferation (2/21), and polyps (3/21), and all had chronic inflammation. Dogs had epistaxis (14/21), sneezing (9/21), decreased airflow (8/21), congestion (6/21), and discharge (5/21). In addition to a mass lesion, computed tomography findings (n = 19) included turbinate lysis (10/19), cribriform plate and orbit erosion (4/19), and contralateral extension (8/19). In 16 dogs with outcome data collected 0-49 months after diagnosis, 13 had continued respiratory symptoms, 11 of which received medical management; 2 of the 3 dogs with improvement had radiotherapy/radiofrequency procedures after biopsy. Eight dogs were alive, 5 were euthanized due to the hamartoma (median survival 9.3 months), 2 died from unknown causes, and 1 died from a seizure. Nasal hamartomas are often locally destructive mass lesions that cause recurrent upper respiratory symptoms and may require more aggressive therapeutic interventions for disease control. Diagnosing nasal hamartomas requires integrating the clinical history, imaging results, adequate biopsy sampling of the mass, and the presence of characteristic histologic features.

Radiation therapy (RT) is a common treatment modality for dogs with locally advanced head and neck tumors. Most dogs experience a clinical benefit secondary to RT, however, long term remissions are rare. This study evaluates the feasibility and safety profile of intratumoral CBC101 (a proprietary hydrogel-based injectable resiquimod formulation), a toll-like receptor (TLR) 7/8 agonist with immunomodulatory properties, when used in combination with radiation therapy. Three dogs with histologically confirmed head/neck cancers were prospectively enrolled. A baseline CT scan was performed. Dogs received palliative radiation therapy (8 Gy × 4) in conjunction with intratumoral CB101. A follow-up CT scan was performed at week 12 to assess tumor response and to evaluate for metastatic disease. Intratumoral CB101 was well-tolerated, feasible, and produced minimal adverse effects. Only one grade 1 adverse event was attributable to CB101; all other adverse events were expected radiation therapy side effects. The data obtained from this preliminary study will be used for further investigation into appropriate dosing and timing of intratumoral resiquimod or other TLRs, with eventual escalation into phase II and III clinical trials.

OBJECTIVE:The aim of this study was to develop and describe pre- and intra-operative sentinel lymph node (SLN) mapping techniques in dogs with thyroid carcinoma. STUDY DESIGN:A prospective, pilot clinical trial was performed. ANIMALS:Six client-owned dogs with unilateral thyroid carcinoma and no overtly metastatic locoregional lymph nodes (LNs) were enrolled. METHODS:All dogs underwent preoperative indirect computed tomography (CT)-lymphography (CTL) with peritumoral iohexol injection and intraoperative SLN mapping with peritumoral injection of a visible dye (methylene blue [MB]) and near-infrared (NIR) fluorescent dye (indocyanine green [ICG]). Subsequent LN extirpation and routine thyroidectomy were performed. All excised tissues were evaluated histologically. RESULTS:Pre- and intra-operative SLN mapping identified at least one SLN in all dogs. A median of one SLN (range, 1-2) was identified on both CTL and intraoperative SLN mapping. Identified SLNs included medial retropharyngeal, cranial deep cervical, and superficial cervical LNs. Variability between pre- and intra-operative SLN findings occurred in 3/6 dogs. A median of two LNs (range, 1-3) were extirpated for each dog. Metastatic carcinoma was diagnosed in extirpated LNs in 2/6 dogs and 3/12 extirpated LNs. CONCLUSION:In this pilot study, preoperative CTL and intraoperative MB and ICG/NIR allowed for identification of SLNs in dogs with thyroid carcinoma. CLINICAL SIGNIFICANCE:Sentinel lymph nodes were identified and extirpated using the described techniques, with nodal metastasis identified in a subset of these dogs due to SLN mapping. Large-scale, powered studies are needed to accurately determine the incidence and prognostic significance of nodal metastasis identified by SLN mapping and extirpation in dogs with thyroid carcinoma.

PURPOSE:To describe the clinical features surgical technique, early and long-term outcome with or without surgery, and histopathological findings of melanocytic anterior uveal lesions in young dogs. METHODS:Medical records of dogs at a guide dog facility removed from training due to a pigmented iris lesion were reviewed from 2014 to 2021. Selected dogs had surgical iridectomies performed. RESULTS:Iridal melanocytic lesions were characterized as well-delineated, pigmented, and flat (nevus) or raised (mass) lesions of the iris. Forty dogs (18 Labrador retrievers, 18 German shepherd dogs, 1 Golden retriever, 3 Labrador/Golden mixes) ranging from 0.5 to 3.1 years of age were affected unilaterally (n = 35) or bilaterally (n = 5). Sector iridectomy was performed in 13 dogs with prominent and well-isolated mass lesion and enucleation was carried out in 2 dogs with extensive lesions, while all other cases were monitored without surgical intervention. Postoperative complications included dyscoria (13/13), focal posterior synechia (9/13) and focal nonprogressive cataract (8/13). All eyes remained visual and comfortable up to 6.2 years post-iridectomy with no clinically identifiable local recurrence. Histopathology was consistent with uveal melanocytoma in all samples obtained surgically. All cases that did not undergo surgery remained free of complications up to 4.5 year post diagnosis. CONCLUSION:Melanocytic anterior uveal lesions may be overrepresented in certain lineages of breeds and be present at a young age. While none of the eyes developed complications when monitored without surgery, early surgical excision of the mass by sector iridectomy yields noteworthy functional outcome and retention of a comfortable globe.

Tumor-infiltrating lymphocyte (TIL) density plays an important role in anti-tumor immunity and isassociated with patient outcome in various human and canine malignancies. As a first assessment of the immune landscape of the tumor microenvironment in canine renal cell carcinoma (RCC), we retrospectively analyzed clinical data and quantified CD3, FoxP3, and granzyme B immunostaining in formalin-fixed paraffin-embedded tumor samples from 16 dogs diagnosed with renal cell carcinoma treated with ureteronephrectomy. Cell density was low for all markers evaluated. Increased numbers of intratumoral FoxP3 labelled (+) cells, as well as decreased granzyme B+: FoxP3+ TIL ratio, were associated with poor patient outcomes. Our initial study of canine RCC reveals that these tumors are immunologically cold and Tregs may play an important role in immune evasion.

Reagents for immunohistochemistry studies.

Supplementary Methods, Figure Legends 1-6 from Heterozygosity for Hypoxia Inducible Factor 1α Decreases the Incidence of Thymic Lymphomas in a p53 Mutant Mouse Model

PDF file - 1196K, Supplementary Figure 1. Phenotypic analysis of FAP+ stromal cells in untreated TC1 flank tumors in C57BL/6 mice. Supplementary Figure 2. Depletion of FAP+ cells. Supplementary Figure 3. Persistence and antitumor activities of FAP-CAR T cells employing either human 4-1BB (73.3-hBBz) or mouse CD28 (73.3-m28z) co-stimulatory domain in mice and their in vitro activity. Supplementary Figure 4. Deletion of DGKzeta enhanced effector functions and in vivo persistence of FAP-CAR T cells. Supplementary Figure 5. Body weight of FAP-CAR T cells-treated mice remained constant or increased. Supplementary Figure 6. Histology of bone marrows and pancreas following treatment with FAP-CAR T cells. Supplementary Figure 7. Activation-induced cell death of FAP-CAR T cells. Supplementary Figure 8. Differential FAP expression on tumor and pancreatic FAP+ stromal cells. Supplementary Figure 9. mAb 73.3 and mAb FAP5 are specific for distinct epitopes of murine FAP expressed by fibroblasts.

Supplementary Figure S1. HIF1α is dispensable for pancreas development. Supplementary Figure S2. Additional characterization of KrasG12D;Hif1αKO animals. Supplementary Figure S3. Disease spectrum of KrasG12D and KrasG12D;Hif1αKO mice. Supplementary Figure S4. Additional characterization of immune cell infiltration in KrasG12D and KrasG12D;Hif1αKO pancreata. Supplementary Figure S5. HIF1α deficiency increases the proportion of B1b cells in spleen. Supplementary Figure S6. B cell depletion inhibits development of microinvasive neoplasms in KrasG12D;Hif1αKO pancreata. Supplementary Figure S7. Characterization of pancreatic immune infiltrates following αCD20 mAb administration. Supplementary Figure S8. Effects of HIF1α on expression of cytokines and chemokines.

Supplementary Figures 1-5 from Combining ATR Suppression with Oncogenic Ras Synergistically Increases Genomic Instability, Causing Synthetic Lethality or Tumorigenesis in a Dosage-Dependent Manner

Canine cutaneous epitheliotropic T-cell lymphoma is a neoplasm with heterogeneous clinical and histopathological presentations. Survival times and responses to therapy are variable, and indicators to predict outcomes are lacking. Clinical and histopathological parameters from 176 archival cases from the University of Pennsylvania and University of Bern (2012–2018) were investigated for associations with clinical outcomes. Histopathological evaluation used digitized whole slide images and QuPath software. Cases included 107 female and 69 male dogs from 48 breeds, with a mean age of 10.4 years. Most common clinical signs were erythema ( n = 131), crusting ( n = 108), and scaling ( n = 102). Affected sites were haired skin ( n = 159), lip ( n = 74), nasal planum ( n = 49), and paw pads ( n = 48). The median survival time (MST) was 95 days (1–850). Dogs had 4.26-fold and 2.82-fold longer MST when treated with chemotherapy and prednisone, respectively, than when receiving supportive care. Haired skin involvement (hazard ratio [HR]: 2.039, 95% confidence interval [CI]: 1.180–3.523), erosions/ulcers (HR: 1.871, 95% CI: 1.373–2.548), nodules (HR: 1.496, 95% CI: 1.056–2.118), and crusting (HR: 1.454, 95% CI: 1.061–1.994) were clinical parameters predicting poor outcomes, whereas complete posttherapeutic clinical remission (HR: 0.469, 95% CI: 0.324–0.680) and a stable disease (HR: 0.323, 95% CI: 0.229–0.456) were associated with longer survival. Histopathological features associated with the increased risk of death were extensive infiltration of the panniculus (HR: 2.865, 95% CI: 1.565-4.809), mitotic count ≥7/high-power field (HR: 3.027, 95% CI: 2.065–4.439), cell diameter ≥10.0 µm (HR: 2.078, 95% CI: 1.281–3.372), and nuclear diameter ≥8.3 µm (HR: 3.787, 95% CI: 1.647–8.707).

Alteration of tumor structure by FAP-CAR T cells in murine PDAs.

Supplementary Figure 4 from Heterozygosity for Hypoxia Inducible Factor 1α Decreases the Incidence of Thymic Lymphomas in a p53 Mutant Mouse Model

Canine cancer, a significant cause of mortality in domestic dogs, is a powerful comparative model for human cancers. Revealing genetic alterations driving the oncogenesis of canine cancers holds great potential to deepen our understanding of the cancer biology, guide therapeutic development, and improve cancer management in both dogs and people. Next generation sequencing (NGS) based-diagnostic panels have been routinely used in human oncology for the identification of clinically-actionable mutations, enabling tailored treatments based on the individual's unique mutation profiles. Here, we report the development of a comprehensive canine cancer gene panel, the Canine Oncopanel, using a hybridization capture-based targeted NGS method. The Canine Oncopanel allows deep sequencing of 283 cancer genes and the detection of somatic mutations within these genes. Vigorous optimization was performed to achieve robust, high-standard performance using metrics of similar cancer panels in human oncology as benchmarks. Validation of the Canine Oncopanel on reference tumour samples with known mutations demonstrated that it can detect variants previously identified by alternative methods, with high accuracy and sensitivity. Putative drivers were detected in over 90% of clinical samples, showing high sensitivity. The Canine Oncopanel is suitable to map mutation profiles and identify putative driver mutations across common and rare cancer types in dogs. The data generated by the Canine Oncopanel presents a rich resource of putative oncogenic driver mutations and potential clinically relevant markers, paving the way for personalized diagnostics and precision medicine in canine oncology.

Histiocytic sarcoma (HS) is a rare and aggressive tumor in humans with no universally agreed standard of care therapy. Spontaneous canine HS exhibits increased prevalence in specific breeds, shares key genetic and biologic similarities with the human disease, and occurs in an immunocompetent setting. Previous data allude to the immunogenicity of this disease in both species, highlighting the potential for their successful treatment with immunotherapy. Quantification of CD3 tumor-infiltrating lymphocytes (TIL) in five cases of human HS revealed variable intra-tumoral T cell infiltration. Due to the paucity of human cases and lack of current model systems in which to appraise associations between anti-tumor immunity and treatment-outcome in HS, we analyzed clinical data and quantified TIL in 18 dogs that were previously diagnosed with localized HS and treated with curative-intent tumor resection with or without adjuvant chemotherapy. As in humans, assessment of TIL in biopsy tissues taken at diagnosis reveal a spectrum of immunologically “cold” to “hot” tumors. Importantly, we show that increased CD3 and granzyme B TIL are positively associated with favorable outcomes in dogs following surgical resection. NanoString transcriptional analyses revealed increased T cell and antigen presentation transcripts associated with prolonged survival in canine pulmonary HS and a decreased tumor immunogenicity profile associated with shorter survivals in splenic HS. Based on these findings, we propose that spontaneous canine HS is an accessible and powerful novel model to study tumor immunology and will provide a unique platform to preclinically appraise the efficacy and tolerability of anti-cancer immunotherapies for HS.