Canine Tumors Research Articles

Characterisation and Sensitivity of a Canine Mast Cell Tumour Line to Oncolytic Viruses.

Canine mast cell tumours (MCTs) are one of the most common skin cancers of dogs. Surgical removal is the primary treatment, but recurrence and metastasis can occur even with low-grade tumours. As a result, new treatment strategies are being sought. We tested the potential of several oncolytic viruses (OVs) to infect and kill a cell line isolated from a canine MCT. Employing a resazurin-based metabolic assay and flow cytometry technology, we used recombinant vesicular stomatitis virus (rVSV-Δm51), avian orthoavulavirus-1 (AOaV-1), and Orf viruses in our assessment. Our study aimed to evaluate the potential of oncolytic virotherapy in treating canine cancers. We found that MCT-1 cells showed different sensitivities to the OVs, with rVSV-Δm51 showing the most promising results invitro. These findings suggest that further investigation into using OVs for treating canine MCTs is needed, although clinical efficacy is yet to be determined.

TMOD-04. SAFETY AND EFFICACY DATA FROM A CLINICAL TRIAL OF SONODYNAMIC THERAPY WITH 5-ALA HCL ORAL SOLUTION AND CV-01 DELIVERED WHOLE HEMISPHERIC LOW-INTENSITY NON-ABLATIVE ULTRASOUND IN PET FRENCH BULLDOGS WITHDE NOVO NATURALLY OCCURRING HIGH-GRADE GLIOMA

Abstract To date, no animal model has been able to accurately test emerging therapeutics for high-grade glioma. Pet dogs’ high-grade gliomas closely mimic human tumors histopathologically and radiologically as well as with poor clinical survival. Dogs with these tumors have notably shorter survival than humans, with French Bulldogs showing the shortest survival of all breeds affected, aiding swift therapeutic evaluations. We report the first use of the novel CV-01 device delivering non-ablative low-intensity diffuse ultrasound (LIDU) with oral 5-ALA as a recurrent high-grade glioma treatment in a veterinary safety and efficacy trial. This Phase 1 study focused on safety, with secondary outcomes assessing histopathological efficacy markers (CC3, Iba1) and overall survival. After one SDT treatment pre-resection, treatments every 3-4 weeks were administered to eight French Bulldogs, totaling 60 administrations (average of 7.5 total treatments/patient). The control group matched breed, age, and histopathologic diagnosis. Average age was 6.35 years (range: 4.8 – 7.8 years), slightly older than controls (5.9 years, range: 3.0 - 9.9 years). No complications or toxicities were noted, and MRI scans showed no damage to the normal brain. Histopathologic analysis from four canine tumor samples revealed increased apoptosis and immune activation markers post-SDT (e.g. cleaved caspase 3 [CC3] and ionized calcium-binding adaptor molecule 1 [Iba1]), indicating selective tumor cell death. Median overall survival in the treatment group reached 205.5 days (6.8 months) compared to 55 days (1.8 months) in controls, with the longest survival at 587 days (versus 213 in controls). Although preliminary, these results affirm the safety of 5-ALA-mediated SDT in canine glioma patients. A multi-center, First-In-Human trial in recurrent high-grade glioma recently completed enrollment, aiming to further validate canine trials for emerging high-grade glioma therapeutics.

Longitudinal Study of Transcriptomic Changes Occurring over Six Weeks of CHOP Treatment in Canine Lymphoma Identifies Prognostic Subtypes

The majority of canine lymphoma patients treated with the standard of care, the CHOP chemotherapy protocol, initially achieve remission but eventually relapse with a multi-drug-resistant phenotype. This study assesses gene expression profiles of canine lymphoma tumor cell populations using RNA-Seq data from 15 matched patient samples taken prior to treatment and again six weeks into treatment with CHOP. Two distinct clusters were present in the t-SNE dimensionality reduction of the gene expression profiles. There was a significant difference in progression-free survival (PFS) between the cluster groups, with a median of 43.5 days in a group of six patients and 185 days in another group of nine patients. Comparing the group with shorter PFS to the group with longer PFS, we identified 265 significantly enriched GO:BP terms in 3874 significantly up-regulated genes and 740 significantly enriched GO:BP terms in 3236 significantly down-regulated genes. Comparing the six-week timepoint against the initial timepoint, in the group with longer PFS, we identified 277 significantly enriched GO:BP terms in 413 significantly up-regulated genes and 222 significantly enriched GO:BP terms in 267 significantly down-regulated genes. In the group with shorter PFS, we only identified 27 significantly differentially expressed genes, for this comparison. We found DNA damage response genes to be enriched in the down-regulated genes in both comparisons. These results identify and characterize two transcriptionally distinct groups of canine lymphoma patients with significantly different responses to CHOP chemotherapy.

Artificial intelligence can be trained to predict c-KIT-11 mutational status of canine mast cell tumors from hematoxylin and eosin-stained histological slides.

Numerous prognostic factors are currently assessed histologically and immunohistochemically in canine mast cell tumors (MCTs) to evaluate clinical behavior. In addition, polymerase chain reaction (PCR) is often performed to detect internal tandem duplication (ITD) mutations in exon 11 of the c-KIT gene (c-KIT-11-ITD) to predict the therapeutic response to tyrosine kinase inhibitors. This project aimed at training deep learning models (DLMs) to identify MCTs with c-KIT-11-ITD solely based on morphology. Hematoxylin and eosin (HE) stained slides of 368 cutaneous, subcutaneous, and mucocutaneous MCTs (195 with ITD and 173 without) were stained consecutively in 2 different laboratories and scanned with 3 different slide scanners. This resulted in 6 data sets (stain-scanner variations representing diagnostic institutions) of whole-slide images. DLMs were trained with single and mixed data sets and their performances were assessed under stain-scanner variations (domain shifts). The DLM correctly classified HE slides according to their c-KIT-11-ITD status in up to 87% of cases with a 0.90 sensitivity and a 0.83 specificity. A relevant performance drop could be observed when the stain-scanner combination of training and test data set differed. Multi-institutional data sets improved the average accuracy but did not reach the maximum accuracy of algorithms trained and tested on the same stain-scanner variant (ie, intra-institutional). In summary, DLM-based morphological examination can predict c-KIT-11-ITD with high accuracy in canine MCTs in HE slides. However, staining protocol and scanner type influence accuracy. Larger data sets of scans from different laboratories and scanners may lead to more robust DLMs to identify c-KIT mutations in HE slides.

Circulating Endocannabinoids in Canine Cutaneous Mast Cell Tumor.

A cutaneous mast cell tumor (cMCT) is among the most common tumors in dogs. Endocannabinoids (eCBs) belong to the endocannabinoid system (ECS), which involves also cannabinoid receptors and an enzymatic system of biosynthesis and degradation. In this study, plasma levels of N-arachidonoylethanolamine (AEA), 2-arachidonoylglycerol (2-AG), N-palmitoylethanolamine (PEA), and N-oleoylethanolamine (OEA) were evaluated in 17 dogs with MCTs of varying histological grades and clinical stages, as well as in a control group of 11 dogs. Dogs affected by cMCT had higher plasma levels of 2-AG (p = 0.0001) and lower levels of AEA (p = 0.0012) and PEA (p = 0.0075) compared to the control group, while no differences were observed at the OEA level between healthy and cMCT dogs (p = 0.9264). The ability of eCBs to help discriminate between healthy and cMCT dogs was interrogated through the area under the ROC curve (AUC). An accuracy of 0.98 (95% confidence interval [CI], 0.94-1.02) was found for 2-AG, of 0.85 (95% CI, 0.71-0.99) for AEA, and of 0.81% for PEA (95% CI, 0.64-0.69). Values > 52.75 pmol/mL for 2-AG showed 94% sensitivity and 90% specificity in distinguishing cMCT. This is the first study to demonstrate alterations in plasmatic levels of eCBs in dogs affected by MCTs, suggesting the significance of these biomarkers in the tumorigenic process and their potential use as biomarkers in the future.

Large Scale Comparative Analysis of Canine and Human Osteosarcomas Uncovers Conserved Clinically Relevant Tumor Microenvironment Subtypes.

Osteosarcoma is an aggressive bone cancer lacking robust biomarkers for personalized treatment. Despite its scarcity in humans, it is relatively common in adult pet dogs. This study aimed to analyze clinically annotated bulk tumor transcriptomic datasets of canine and human osteosarcoma patients to identify potentially conserved patterns of disease progression. Bulk transcriptomic data from 245 pet dogs with treatment-naïve appendicular osteosarcoma were analyzed using deconvolution to characterize the tumor microenvironment (TME). The TME of both primary and metastatic tumors derived from the same dog was compared, and its impact on canine survival was assessed. A machine learning model was developed to classify the TME based on its inferred composition using canine tumor data. This model was applied to 8 independent human osteosarcoma datasets to assess its generalizability and prognostic value. This study found three distinct TME subtypes of canine osteosarcoma based on cell type composition of bulk tumor samples: Immune Enriched (IE), Immune Enriched Dense Extra-Cellular Matrix-like (IE-ECM), and Immune Desert (ID). These three TME-based subtypes of canine osteosarcomas were conserved in humans and could predict progression-free survival outcomes of human patients, independent of conventional prognostic factors such as percent tumor necrosis post standard of care chemotherapy treatment and disease stage at diagnosis. These findings demonstrate the potential of leveraging data from naturally occurring cancers in canines to model the complexity of the human osteosarcoma TME, offering a promising avenue for the discovery of novel biomarkers and developing more effective precision oncology treatments.

Immunohistochemical expression of CYP11A1, CYP11B, CYP17, and HSD3B2 in functional and nonfunctional canine adrenocortical tumors.

Functionality of human adrenal tumors is inferred by CYP11B1 (cortisol synthase) expression, CYP11B2 (aldosterone synthase) expression, or both. Nonfunctional canine adrenal tumors have low expression of steroidogenic enzymes, whereas aldosterone-producing tumors express CYP11B, and cortisol-producing tumors express both CYP11B and CYP17. Twenty-two client-owned dogs with adrenocortical tumors (ACT) (8 nonfunctional, 7-cortisol producing, 2 aldosterone-producing and 5 functional noncortisol producing) and 2 dogs with normal adrenal glands. Retrospective case series. Adrenal functionality was determined from clinical signs and endocrine testing. CYP11A1, CYP11B, CYP17, and HSD3B2 expression was detected by immunohistochemistry on formalin-fixed paraffin-embedded adrenal tissue. Protein expression was semiquantified by 2 blinded observers using H-scoring (results reported as median [range]) and compared in nonfunctional and cortisol-producing adrenal tumors by Mann-Whitney U tests. CYP11A1, CYP11B, and HSD3B2 were present within all cortical layers of normal adrenal glands, and CYP17 was expressed within the zona fasciculata and zona reticularis. Expression of CYP11A1 (191.25 [97.5-270] vs. 175 [102.5-295] P = .69), CYP11B (190 [130-265] vs. 147.5 [95-202.5]; P = .07), CYP17 (177.5 [87.5-240] vs. 247.5 [55-292.5]; P = .40), and HSD3B2 (230 [47.5-295] vs. 277.5 [67.5-295]; P = .34) were not significantly different between cortisol-producing and nonfunctional ACT. Our findings suggest it is not possible to determine functionality of canine ACT by immunohistochemistry for steroidogenic enzymes. Tumor size cannot be used to infer functionality of adrenal tumors.

Investigation of the Theragnostic Role of KIT Expression for the Treatment of Canine Mast Cell Tumors with Tyrosine Kinase Inhibitors.

Several reports have indicated that canine MCTs express a mutated form of a tyrosine kinase receptor, namely KIT, that is involved in abnormal mast cell growth and differentiation. Currently, the post-surgical prognosis for MCTs is related to three different KIT immunohistochemical expression patterns. However, to our knowledge, there are few studies specifically exploring the efficacy of treatment with tyrosine kinase inhibitors related to KIT staining pattern. The purpose of this study was to investigate the potential theragnostic role of KIT expression patterns by studying their correlation to the overall survival and progression-free survival in dogs treated with only tyrosine kinase inhibitors immediately after surgery. We selected 66 cases of canine cutaneous MCTs with complete clinical background. A statistical analysis was performed to assess the overall survival status. Our data suggest an important role of KIT in the etiopathogenesis of canine MCTs and indicate that the anomalous cytoplasmatic distribution of KIT is potentially related to a lower efficacy of tyrosine kinase inhibitors, thus providing a significant prognostic information about the treatment outcome.

Relative Tumour Volume in Canine Oral Melanoma Staging and Prognosis.

Melanoma is one of the most common canine oral malignant tumours and is highly aggressive and metastatic, even at the early stages of development. Surgery relies on wide excision of the primary tumour and regional lymphadenectomy, with or without adjuvant therapy. Tumour location and size are important when considering staging, which ultimately affects the curative intent of surgery. Nevertheless, absolute tumour volume (TV) is not related to the vast phenotypic variability within canine breeds. This study aimed to determine the cutoff values of two ratios-tumour-to-head volume (THR) and tumour-to-body volume (TBR)-and assess whether they could be associated with the odds of finding metastasis at presentation and/or the likelihood of achieving tumour-free excision margins. A retrospective case series involving 51 dogs was used to evaluate the preoperative head/neck and chest computed tomography and histopathology of the primary mass and excised lymph nodes. Higher TV, THR% and TBR% values were associated with bone lysis and mitotic count (MC). The Ki67 index was significantly associated with local and distant metastases at presentation, whereas MC was associated with local metastasis alone. Tumour-infiltrated surgical margins were associated with caudally located tumours, regardless of the tumour size. Dogs with lymph node metastasis at presentation were seven times more prone to have local relapse. TV, THR% and TBR% values were positively associated with local lymph node metastasis at presentation. Cutoff values for both TV and TBR% were proposed to predict lymph node metastasis at presentation (TV = 6.423 cm3 and TBR% = 0.043), being supported by post-surgical survival analysis.

Evaluation of canine and feline tumors in Morocco: Results of a prospective observational study of 250 cases (2020-2023).

This work aimed to evaluate the histologic tumor types and patient characteristics of canine and feline neoplasias in Morocco. In a prospective, observational study, 250 tumor samples were collected from veterinary clinics in Morocco. For each case, breed, age, sex, neuter status, and tumor site and histotype were analyzed. Among the 250 tumors, 201 (80.4%) were from dogs and 49 (19.6%) from cats. Most common tumor location in dogs was the reproductive tract (36.8%), followed by skin and soft tissues (27.4%) and mammary gland (14.9%). In cats, most tumors originated from the skin and soft tissues (55.1%), followed by mammary gland (20.4%) and oral cavity (14.3%). Commonest canine histologic tumor types were transmissible venereal tumor (CTVT11Abbreviations: CTVT, Canine transmissible venereal tumor; PAS, Periodic Acid-Schiff; IHC, Immunohistochemistry; AR, Antigen Retrieval; n, number; SD, Standard deviation; WHO, World Health Organization; Vet ICD-O, The Veterinary International Classification of Diseases for Oncology Canine Tumors First Edition; SCC, Squamous cell carcinoma.) (31.8%) and mammary carcinoma (14.4%). Squamous cell carcinoma (34.7%) and mammary carcinoma (20.4%) represented the most frequent feline neoplasms. Median age of dogs and cats at diagnosis was 7 and 10 years, respectively. Gender distribution was even in dogs; in cats, females were overrepresented. Most cats and about half of dogs were mixed-breed. The evaluated canine and feline neoplasias show differences in their tumor types and patient characteristics when compared to populations from other countries, in part based on the high number of CTVT and - possibly solar-induced –feline skin tumors.

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.

Long-Term Survival in Canine Hepatosplenic T-Cell Lymphoma Treated with Toceranib Phosphate Following Splenectomy: A Case of Atypical Lymphoma

Toceranib phosphate (toceranib) is approved for canine mast cell tumor treatment. However, no long-term response to toceranib in canine HSTCL has been reported. Here, we describe a case of a 10-year-old castrated mixed-breed dog that presented with a 3-month history of weight loss, polydipsia, and polyuria. The clinicopathological and imaging abnormalities included icterus, biliary obstruction, and splenomegaly with multiple diffuse splenic hypoechoic nodules. On day 21, a cholecystectomy was performed to remove the obstruction, followed by a liver biopsy and splenectomy. Cytology of the spleen and liver showed many small lymphocytes with intracytoplasmic granules (sGLs). Splenic and hepatic infiltration of neoplastic CD3/granzyme B-positive small cells and lymphocytic cholecystitis with granzyme B-negative small cells were noted. T-cell receptor gene clonal rearrangements were observed in the liver tissues. The dog was diagnosed with a hepatosplenic T-cell lymphoma (HSTCL) of sGLs concurrent with lymphocytic cholecystitis. The icterus resolved after surgery, but there was progressive elevation of liver enzyme levels. Toceranib was administered from day 39, resulting in decreased liver enzyme levels, and the dog remained in good condition. The dog stayed in remission after toceranib administration and survived for 460 days. Toceranib should be considered an effective treatment option for canine HSTCL.

Evaluation of diode laser for excision of canine cutaneous tumours

Evaluation of diode laser for excision of canine cutaneous tumours

Computed tomography radiomics models of tumor differentiation in canine small intestinal tumors.

Radiomics models have been widely exploited in oncology for the investigation of tumor classification, as well as for predicting tumor response to treatment and genomic sequence; however, their performance in veterinary gastrointestinal tumors remains unexplored. Here, we sought to investigate and compare the performance of radiomics models in various settings for differentiating among canine small intestinal adenocarcinoma, lymphoma, and spindle cell sarcoma. Forty-two small intestinal tumors were contoured using four different segmentation methods: pre- or post-contrast, each with or without the inclusion of intraluminal gas. The mesenteric lymph nodes of pre- and post-contrast images were also contoured. The bin settings included bin count and bin width of 16, 32, 64, 128, and 256. Multinomial logistic regression, random forest, and support vector machine models were used to construct radiomics models. Using features from both primary tumors and lymph nodes showed significantly better performance than modeling using only the radiomics features of primary tumors, which indicated that the inclusion of mesenteric lymph nodes aids model performance. The support vector machine model exhibited significantly superior performance compared with the multinomial logistic regression and random forest models. Combining radiologic findings with radiomics features improved performance compared to using only radiomics features, highlighting the importance of radiologic findings in model building. A support vector machine model consisting of radiologic findings, primary tumors, and lymph node radiomics features with bin count 16 in post-contrast images with the exclusion of intraluminal gas showed the best performance among the various models tested. In conclusion, this study suggests that mesenteric lymph node segmentation and radiological findings should be integrated to build a potent radiomics model capable of differentiating among small intestinal tumors.

Surgical Management of Canine Transmissible Venereal Tumor with Adjunctive Chemotherapy Combination

One male and a female 2-year-old Neapolitan Mastiff dogs weighing 41 and 40 kg, respectively, were presented to the University Veterinary Teaching Hospital, Jos, Nigeria, with complaints of continuous bleeding from the prepuce and vulva which were first observed about 2 months before presentation. Clinical examination revealed preputial bleeding of the male dog and serosanguinous vulva discharges with the presence of palpable masses with multiple nodules that were cauliflower-like. Cytological evaluations of smears from preputial and vaginal swabs revealed characteristic round cells with large eccentric nuclei, large nuclear-cytoplasmic ratio, and intracytoplasmic vacuolations as well as anisocytosis and anisokaryosis. Based on these cytological features, a diagnosis of canine transmissible venereal tumor (CTVT) was made in each case. Blood samples were collected for hematology and clinical chemistry. Debulking of the masses was carried out under general anesthesia using atropine sulfate and chlorpromazine as pre-anesthetics and Ketamine hydrochloride as induction and maintenance anesthetics. Following debulking, the resulting defect was reconstructed and the surgical wound was managed by daily wound cleaning and the administration of vincristine sulfate (0.025 mg/kg) slowly intravenously, ivermectin (0.3 mg/kg) subcutaneously, and piroxicam (0.3 mg/kg) and 20% amoxicillin (20 mg/kg) intramuscularly. There were no observed known vincristine sulfate-associated adverse effects as the dogs recovered and were discharged 3-week post-tumor debulking with no recurrence within 6 months of follow-up examinations. The debulked mass histologically showed several sheets of round neoplastic cells with prominent nuclei, mitotic figures, and infiltrating lymphocytes. Based on these findings, a diagnosis of CTVT was further confirmed. The hemogram showed moderate leukocytosis at day 1 in the bitch with a mild left shift at days 1 and 14 while clinical chemistry showed a marked increase in alkaline phosphatase, moderate increase in serum creatinine, and mild hypoproteinemia. In conclusion, management of CTVT with adjunctive vincristine sulfate and ivermectin combination resulted in complete healing with amelioration of known associated adverse effects.

Exploring the Epidemiology of Melanocytic Tumors in Canine and Feline Populations: A Comprehensive Analysis of Diagnostic Records from a Single Pathology Institution in Italy.

MTs are prevalent in dogs, representing the most frequent oral malignancy, compared to cats, in which ocular melanomas predominate. This study investigates the canine and feline MT epidemiology (2005-2024) of cases submitted to the Veterinary Pathology Service (University of Perugia). Among the canine neoplasms, 845 (4%) were melanocytic: 329 (39%) melanocytomas; 512 (61%) melanomas. Of these, 485 (57%) were cutaneous (4% of canine cutaneous neoplasms), 193 (23%) were oral (50% of oral canine neoplasms), and 104 (12%) were mucocutaneous. The average age of affected dogs was 10 years. Older dogs were more likely to have melanomas compared to melanocytomas (p < 0.001). There were 60 (1%) feline MTs: 6 (10%) melanocytomas; 53 (88%) melanomas. Of these, 29 (48%) were cutaneous (1% of feline cutaneous tumors), 18 (30%) were ocular, and 9 (15%) were oral (22% of feline oral tumors). The average age of affected cats was 11 years. In dogs, mucocutaneous melanomas were more common compared to cutaneous ones (p < 0.05); oral melanomas were more common compared to all other sites (p < 0.001). In cats, ocular melanomas were more common compared to cutaneous ones (p < 0.05). Our study provides the MT prevalence in a selected canine and feline population, revealing MT epidemiological patterns, highlighting species-specific differences in the tumor prevalence, localization, and age distribution.

Whole Mitochondrial Genome Sequencing Analysis of Canine Testicular Tumours.

Currently, the molecular background based on mitochondrial DNA (mtDNA) analysis of canine testicular tumours is underestimated. The available data mostly focus on histopathological evaluations, with a few reports of nuclear genome (nDNA) studies. Tumourigenesis represents a highly complex and diverse genetic disorder, which can also encompass defects in mtDNA. The aim of this study was to identify molecular changes in whole mitochondrial genome sequences obtained from dogs affected by testicular tumours. Samples of blood, tumour, and healthy tissue were collected from each animal, and mtDNA (ultimately 45 samples) was subsequently sequenced. Thereafter, protein analyses were performed to assess the impact of the identified molecular alterations on the amino acid level. The total number of observed changes included 722 SNPs, 12 mutations, 62 indels, 5 indel mutations, and 35 heteroplasmic sites. The highest number of mtDNA variants in protein-coding genes COX1, COX3, ATP6, ND1, ND4, and ND5 was observed. Interestingly, SNPs were found in 10 out of 22 tRNA genes. Most of the identified mtDNA defects were synonymous changes at the amino acid level. Also, polymorphisms and heteroplasmy were frequently observed in the variable number of tandem repeat (VNTR) regions, especially in its fragment spanning 16,138-16,358 bp. Based on the obtained results, it was possible to select 11 polymorphisms that occurred in all the tested samples (benign, malignant) and an additional five SNPs identified only in benign neoplasms. The comprehensive analysis of malignant testicular tumours demonstrated a significant diversity in their molecular profiles, with changes ranging from 17 to 101 per sample.

Cannabinoid receptor-2 expression in canine multicentric diffuse large B-cell lymphoma: An immunohistochemical, digital pathology and clinical analysis

The cannabinoid 2 receptor (CB2R) is a crucial element of the endocannabinoid system (ECS), which is predominantly expressed on cells of the reticuloendothelial system. Alterations in CB2R expression have shown a prognostic role in various human neoplastic diseases and its expression has been studied in canine mast cell tumours (MCT). Canine diffuse large B-cell lymphoma (DLBCL) is the most common lymphoma in dogs and has a variable clinical behaviour. Expression of CB2R was assessed by means of immunohistochemistry in fifteen dogs with proven histological diagnosis of DLBCL. A semiquantitative and quantitative assessment of immunoreactivity (IR) by digital analysis was performed in all cases. Our results indicate that CB2R expression is conserved in canine DLBCL but does not correlate with clinical outcome.

Preliminary Evidence of the Possible Roles of the Ferritinophagy-Iron Uptake Axis in Canine Testicular Cancer.

Iron is a key element in spermatogenesis; its metabolic pathway in the testis is strictly regulated. Alterations in iron metabolism are linked to various diseases, including cancer, and changes in iron metabolism-related proteins have been observed in multiple human, mouse and canine tumors. There is limited knowledge about iron metabolism in canine non-neoplastic and neoplastic testes. This study aimed to explore the immunohistochemical expression of molecules involved in iron uptake and storage [Transferrin Receptor 1 (TfR1), ferritin (FTH1), nuclear receptor coactivator 4 (NCOA4)] and PCNA in canine non-neoplastic and neoplastic testicular samples. Non-neoplastic testes showed moderate TfR1 expression in developing germ cells and Sertoli cells, high NCOA4 cytoplasmic immunostaining in the Sertoli cells and occasional cytoplasmic immunopositivity for FTH1 in the spermatogonia and Sertoli cells. In contrast, Leydig cell tumors (LCTs) and Diffuse Type Seminoma (DSEM) exhibited increased expression of TfR1, along with higher PCNA expression, suggesting a higher iron need for proliferation. Intratubular Type Seminoma (ITSEM) showed a higher FTH1 expression, indicating greater iron storage, while the increased NCOA4 expression in the LCTs and DSEM suggested ferritinophagy to release iron for proliferation. Sertoli cell tumors (SCTs) showed only NCOA4 expression. These preliminary findings highlight potential molecular targets for developing new anti-neoplastic treatments in canine testicular tumors.

Investigation of High Frequency Irreversible Electroporation for Canine Spontaneous Primary Lung Tumor Ablation.

In this study, the feasibility of treating canine primary lung tumors with high-frequency irreversible electroporation (H-FIRE) was investigated as a novel lung cancer treatment option. H-FIRE is a minimally invasive tissue ablation modality that delivers bipolar pulsed electric fields to targeted cells, generating nanopores in cell membranes and rendering targeted cells nonviable. In the current study, canine patients (n = 5) with primary lung tumors underwent H-FIRE treatment with an applied voltage of 2250 V using a 2-5-2 µs H-FIRE waveform to achieve partial tumor ablation prior to the surgical resection of the primary tumor. Surgically resected tumor samples were evaluated histologically for tumor ablation, and with immunohistochemical (IHC) staining to identify cell death (activated caspase-3) and macrophages (IBA-1, CD206, and iNOS). Changes in immunity and inflammatory gene signatures were also evaluated in tumor samples. H-FIRE ablation was evident by the microscopic observation of discrete foci of acute hemorrhage and necrosis, and in a subset of tumors (n = 2), we observed a greater intensity of cleaved caspase-3 staining in tumor cells within treated tumor regions compared to adjacent untreated tumor tissue. At the study evaluation timepoint of 2 h post H-FIRE, we observed differential gene expression changes in the genes IDO1, IL6, TNF, CD209, and FOXP3 in treated tumor regions relative to paired untreated tumor regions. Additionally, we preliminarily evaluated the technical feasibility of delivering H-FIRE percutaneously under CT guidance to canine lung tumor patients (n = 2). Overall, H-FIRE treatment was well tolerated with no adverse clinical events, and our results suggest H-FIRE potentially altered the tumor immune microenvironment.