Search Results (427)

Background: Osteosarcoma (OS) is a devasting bone cancer that occurs primarily in pediatric patients, and pet dogs, and treatment options have not advanced in decades. There is a profound need for advancement of treatment options to improve patient prognosis given the grim 70% 5-year survival rate for human patients, and 10–12-month median survival for canine patients. A major hurdle in advancing treatment options is overcoming the immunosuppressive tumor microenvironment to mitigate metastatic disease progression—the leading cause of mortality in OS patients. Methods: We investigated the ability of a mechanical focused ultrasound ablation modality, histotripsy, to induce acute immunomodulation in canine patients with spontaneously occurring OS. Results: Immunomodulation was evident locally and systemically. Tumor gene signatures indicated upregulation of pro-inflammatory signaling pathways and T-cell receptor signaling, and B-cell activation, and systemically, increased monocyte activation was observed within 5 days post-histotripsy ablation. A subset of patients who received histotripsy prior to definitive standard-of-care exceeded the reported expected median survival time of 10–12 months for canine OS patients that received definitive standard-of-care only. Conclusions: Our results demonstrate the promising potential of histotripsy to overcome the immunosuppressive tumor microenvironment. Full article

Osteosarcoma (OS) is characterized by high metastatic potential and marked chemoresistance, with cancer stem cells (CSCs) serving as major drivers of malignant progression. Canine osteosarcoma (cOS) is considered an ideal comparative medicine model for human osteosarcoma (hOS). Accumulating evidence indicates that aberrant glucose metabolism and hexosamine biosynthetic pathway (HBP, hexosamine biosynthetic pathway)/O-linked N-acetylglucosamine (O-GlcNAc)ylation are involved in tumor progression; however, the precise mechanisms by which they regulate stemness in canine osteosarcoma cells remain unclear. In this study, we comprehensively employed glucose gradient culture, untargeted metabolomics, O-GlcNAc-modified proteomics, in vitro gene silencing, and a subcutaneous xenograft model in nude mice. Cellular functional assays revealed that high glucose significantly enhanced malignant phenotypes and stemness properties of canine osteosarcoma cells. Metabolomic analyses confirmed aberrant activation of the HBP in osteosarcoma cells. Further experiments demonstrated that high glucose enhances HBP flux and O-GlcNAcylation in a dose-dependent manner; silencing of glutamine-fructose-6-phosphate transaminase 1 (GFPT1), O-GlcNAc transferase (OGT), and O-GlcNAcase (OGA) verified that both the HBP pathway and O-GlcNAcylation positively regulate malignant biological behaviors and stemness maintenance. In vivo tumorigenesis assays demonstrated that OGT knockdown markedly suppressed osteosarcoma growth. O-GlcNAc-modified proteomics identified transducin-like enhancer of split 3 (TLE3), nuclear receptor corepressor 1 (NCOR1), and neurogenic locus notch homolog protein 2 (NOTCH2) as key differentially modified proteins, predominantly enriched in the Wingless/Integrated (Wnt) and Notch signaling pathways. Collectively, our findings demonstrate that high glucose activates the HBP pathway, elevates global O-GlcNAcylation levels, and modifies TLE3/NCOR1/NOTCH2, thereby promoting stemness maintenance in canine osteosarcoma stem cells. This study provides novel metabolic targets for precision therapy of osteosarcoma. Full article

The extracellular matrix (ECM) is increasingly recognized as an active regulator of breast cancer progression rather than a passive structural scaffold. This narrative review examines how ECM remodeling contributes to tumor aggressiveness through changes in matrix composition, collagen architecture, tissue stiffness, mechanotransduction, stromal permissiveness, immune and metabolic programs, invasion, metastasis and therapeutic response. A structured narrative search of literature published from 1981 to June 2026 was used to support this synthesis. Evidence from breast cancer studies indicates that collagens, fibronectin, laminins, proteoglycans, matricellular proteins, ECM-remodeling enzymes, and matrix-crosslinking pathways regulate integrin–FAK/Src, RhoA–ROCK, PI3K–AKT, MAPK, TGF-β/SMAD, Wnt/β-catenin, and YAP/TAZ signaling. Spontaneous canine mammary tumors are discussed as complementary comparative models that may preserve selected tumor–stroma–ECM interactions under naturally occurring disease conditions while requiring cautious interpretation due to species-specific biological and clinical differences. Proteomics, lipidomics, metabolomics, spatial omics, digital pathology, and artificial intelligence may support ECM-informed biomarker discovery and response prediction. However, translational application requires standardized pathology, reproducible assays, harmonized metadata, external validation, model interpretability, and clinically meaningful endpoints. Overall, ECM-informed comparative oncology is best viewed as a framework grounded in rigorous validation for identifying matrix-defined tumor phenotypes and prioritizing future biomarker and therapeutic strategies. Full article

CMTs are biologically heterogeneous neoplasms for which reliable prognostic biomarkers remain limited. This study investigated the clinical significance of serum cancer antigen 15-3 (CA 15-3) and the immunohistochemical expression of Ki-67 and cyclooxygenase-2 (COX-2) in CMTs. Fifty-four female dogs with histologically confirmed CMTs and twelve healthy controls were prospectively evaluated. Serum CA 15-3 concentrations were measured before surgery and at 21 and 90 days post-mastectomy, while Ki-67 and COX-2 expression were assessed in tumor tissues. CA 15-3 was undetectable in controls and significantly higher in malignant than benign neoplasms (p < 0.05), with moderate correlations with clinical stage (s = 0.59), histological grade (s = 0.64), and the number of nodules (s = 0.42). Levels remained elevated in advanced stages despite surgery. ROC analysis identified a CA 15-3 cutoff of 3.01 IU/mL (AUC = 0.92) for discriminating malignant from benign tumors. Ki-67 correlated with histological grade (ρ = 0.41) but showed limited prognostic accuracy (AUC = 0.63). COX-2 expression lacked significant associations and showed poor discriminatory power (AUC = 0.44). Survival analyses did not identify significant differences among groups. Principal component analysis demonstrated clustering of aggressive CMTs according to biomarker profile. These findings suggest that serum CA 15-3 may represent a useful adjunct prognostic biomarker in canine mammary oncology, while the combination of serum and tissue biomarkers may improve prognostic stratification and may guide therapeutic decision-making in veterinary oncology. These findings support the growing role of biomarker panels in the clinical management of CMTs. Full article

Canine mixed-type mammary carcinomas (CMTs) exhibit remarkable histological and structural heterogeneity, sharing some biological similarities with human breast cancer and supporting their relevance as models in comparative oncology. These tumors frequently contain regions of malignant epithelial cells, areas of mesenchymal differentiation, and ossified tissue, reflecting their complex histological organization. In this exploratory pilot study, we performed MRM-based spatial lipidomic analysis of distinct tumor regions; namely the margin, middle (epithelial/myoepithelial-rich), and central ossified areas. Our region-resolved lipidomic analysis revealed distinct lipidomic signatures across regions, with significant alterations in phosphatidylcholines, phosphatidylethanolamines, sphingomyelins, triacylglycerides, and free fatty acids distribution. The central ossified area showed enrichment in structural lipids and ceramides, while the tumor margin demonstrated enrichment of ether lipids, which may reflect differences in tissue composition and local metabolic environments. By characterizing region-specific lipid profiles, this study provides insights into metabolic heterogeneity within a canine mixed mammary carcinoma. These findings highlight the potential of spatial lipidomics for investigating intratumoral metabolic heterogeneity and provide preliminary data to support future studies in comparative oncology involving canine and human mammary tumors. Full article

Canine mammary tumors have been investigated to determine the causes of malignancy and to promote the development of more effective therapies. The current standard of care, surgical resection where possible, often still results in recurrence of disease. Thus, there is an unmet need for better, more effective therapies that can suppress recurrence in canine patients. Because canine and human mammary cancers, particularly carcinomas and adenocarcinomas, share many similarities in genetic defects, etiology, natural history, and environment, canine mammary cancer cell lines have also been used as effective models of human disease. The genetics and immune response to canine mammary/breast cancers have been investigated to better understand this disease complex and to promote the development of more effective therapies designed to treat individual canine patients. As cancer is a heterogeneous disease, the potential to determine and possibly predict the mechanisms promoting neoplasia would allow the advancement of targeted therapeutic targets/strategies to combat cancer directly. These investigations have led to the development and evaluation of immunotherapies designed to elicit immune recognition of cancer and its suppression, thus improving survival. Hybrid dendritic-cell fusion vaccines and other autologous cancer vaccine formulations have proven effective in suppressing recurrence and extending survival in canine mammary cancer patients following surgical resection. Although current vaccines are somewhat impractical for direct application in veterinary clinics, reported success points the way toward the development of more practical vaccines designed to promote the treatment of canine mammary cancer. They also suggest a possible mechanism whereby removing a tumor from its microenvironment can promote antigenicity by removing local extracellular vesicle-mediated immunosuppression. This review provides a novel perspective on the potential of canine genetics to inform and promote more successful immunotherapies and their value as models of human disease. Full article

Accurate assessment of early indicators of breast cancer (BC) is critical to improve detection strategies and patient prognosis. Our research group takes a comparative species approach to study early BC detection by capitalizing on data from species with inherently low or high incidence of mammary cancer to supplement rare human samples. Circulating microRNAs (c-miRNAs) are a promising class of molecules that have the potential to serve as biomarkers for BC risk and disease detection. The expression of these non-coding RNAs controls numerous cellular processes and their dysregulation is associated with various pathological conditions, including cancer. To explore whether c-miRNA expression profiles can identify individuals with early-stage BC, we conducted a multi-species pilot study. We analyzed biofluid samples (i.e., saliva, serum, and plasma) from patients with early-stage BC and patients with no prior history of cancer and mammosphere-derived epithelial cells (MDECs) from dogs (canines) and horses (equines), species with a relatively high and low incidence of mammary cancer, respectively. We identified 16 candidate c-miRNAs that were upregulated in saliva from patients in the early-stage BC group when compared to the control patient group. Notably, 6 of these c-miRNAs (i.e., miR-361, miR-148b, miR-205, miR-186, miR-223, and miR-197) were also found to be secreted at higher levels by canine MDECs when compared to equine MDECs. Although individual and combinatorial assessment of these six c-miRNAs in a larger human cohort did not confirm their potential association with early breast cancer detection, the data in this study do introduce a novel comparative framework in which species-to-species variation in cancer susceptibility may inform the identification of candidate biomarkers for human disease. Full article

Primary pulmonary adenocarcinoma in dogs is rare, and effective systemic therapies remain limited. To evaluate the molecular basis of potential precision oncology approaches, hotspot mutations in HER2, BRAF, KRAS, and PIK3CA were analyzed in 20 surgically resected canine pulmonary adenocarcinomas and three canine pulmonary adenocarcinoma cell lines. HER2 V659E and BRAF V595E mutations were each detected in 3/20 cases (15%), while KRAS G12V was detected in 1/20 cases (5%). No PIK3CA hotspot mutations were identified. The BRAF V595E mutation was additionally detected in the AZACL2 cell line. Functional analysis demonstrated increased sensitivity of AZACL2 cells to the BRAF inhibitor dabrafenib and MEK inhibitors including trametinib, compared with BRAF wild-type cell lines. These findings support MAPK pathway dependency in BRAF-mutant canine pulmonary adenocarcinoma. The mutation spectrum was broadly consistent with previous reports, suggesting a conserved molecular landscape across geographic regions. Collectively, these data identify BRAF and HER2 alterations as clinically relevant candidates for molecular diagnostics and targeted therapy in canine pulmonary adenocarcinoma. Full article

One of the major obstacles in early cancer detection in dogs is the limited sensitivity in detecting circulating tumor DNAs (ctDNAs) with low abundances. Standard next-generation sequencing (NGS) without error correction typically achieves detection limits around ~1% mutant allele frequency (MAF). We sought to improve the detection sensitivity using a sequential CRISPR-EspCas9 enrichment strategy in which iterative in vitro cleavage (IVC) was combined with PCR amplification to selectively deplete wild-type DNA and enrich rare tumor mutations. Applying the strategy to genomic DNA and cell-free DNA mimics from canine mammary gland tumor cell lines demonstrated that IVC enrichment enabled the detection of cancer-associated PIK3CA H1047R mutations that were undetectable by conventional Sanger sequencing. To evaluate detection sensitivity, we characterized enrichment using synthetic templates for PIK3CA H1047R and other cancer-related mutations, BRAF V596E, and KRAS G12C. We observed that three iterations of sequential IVC achieved ~160, ~15, and ~2.2-fold enrichment for PIK3CA H1047R, BRAF V596E, and KRAS G12C, respectively. Under the present synthetic-template conditions, the analytical LOD reached 0.001% MAF for PIK3CA and 0.01% MAF for BRAF, whereas KRAS showed only modest enrichment and remained practically limited under the current guide design. Together, the results show that the CRISPR-EspCas9 IVC strategy enables selective enrichment of low-frequency single-nucleotide mutant alleles. We anticipate that the finding could be utilized to develop a highly sensitive veterinary liquid biopsy application with further optimization and validation using canine plasma cfDNA. Full article

Background/Objectives: Carvedilol is an adrenergic blocker FDA-approved to improve outcomes in heart failure with reduced ejection fraction. Clinical trials examining whether carvedilol may be cardioprotective in the setting of cancer therapy-induced heart failure have generated mixed results that may depend on the cancer regimen, tumor, or comorbidities. Methods: To investigate the therapeutic potential of carvedilol to mitigate doxorubicin cardiotoxicity in cardiomyocytes, myocardial tissue, and in vivo, independent of confounding factors in clinical studies, we utilized disease-free cardiac slices and cardiomyocytes from mice, dogs, and human in vitro, and in wildtype mice injected with doxorubicin in vivo. We further evaluated the impact of carvedilol in dogs with cancer receiving doxorubicin. Results: In primary canine and murine cardiac slices, carvedilol treatment restored autophagy and prevented apoptosis from doxorubicin. Carvedilol restored mitochondrial energetics in human, canine, and murine models. In wildtype mice challenged with doxorubicin, carvedilol prevented declines in cardiac function and alterations in cardiac structure. In pet dogs with cancer and undergoing doxorubicin treatment, carvedilol was beneficial in preserving cardiac function and structure. Conclusions: Carvedilol activates cardioprotective autophagy, arrests doxorubicin-induced cell death, and improves energetics and cardiac structure and function across species. Full article

Cancer is a leading cause of death in dogs, and incidence rates in dogs exceed those in humans. Current therapeutic options for canine cancer patients remain limited, with most treatments focused on palliative care. Immune checkpoint inhibitors such as anti-PD-1, anti-PD-L1, and anti-CTLA-4 antibodies that have transformed cancer therapy and expanded the therapeutic options in humans could offer the same clinical benefit in canine cancer patients. This study details the engineering and functional characterization of mouse and chimeric mouse–canine anti-canine PD-1 (cPD-1) monoclonal antibodies. We demonstrate that anti-cPD-1 antibodies block the interaction between cPD-1 and its ligand cPD-L1, thereby inhibiting this immune signaling pathway. In a proof-of-concept study in seven companion canine cancer patients, intratumoral therapy with the lead anti-cPD-1 antibody (HugPetmab) was safe, well-tolerated, had no observed adverse events, and showed evidence of tumor control in a subset of injected tumors. These findings support the potential of HugPetmab antibody as an immunotherapeutic option for treating canine cancer patients. Full article

Cryptorchidism is one of the most frequently diagnosed developmental disorders of the male canine reproductive system, defined as the failure of one or both testes to descend into the scrotum. Physiologically, testicular descent is typically completed by six to eight weeks of age, although some authors extend this period to sixteen weeks. Failure of testicular descent beyond this timeframe is considered pathological. The condition has multiple causes and affects between 1% and 10% of the canine population. Genetics is the most significant factor, indicating the hereditary basis of cryptorchidism. In addition, increasing attention has been directed toward the potential impact of environmental and epigenetic factors on the incidence of cryptorchidism, suggesting that the condition may result from complex interactions between genetic predisposition and external influences. The effect of hormones (such as INSL3 and testosterone), mechanical factors (including narrowing of the inguinal canal, abnormalities of the gubernaculum, and shortening of the spermatic cord), and environmental factors (for example, exposure to external estrogens and maternal stress during pregnancy) all contribute to the development of this disorder. Recent results have emphasized the role of the orexin system, particularly the OX2R receptor, in regulating endocrine and reproductive functions in cryptorchid testes. Computed tomography is increasingly utilized in complex cases due to its high precision in localizing retained testes. Clinically, cryptorchidism may present unilaterally or bilaterally. Unilateral cryptorchidism may preserve partial fertility, whereas bilateral cryptorchidism results in complete infertility. Undescended testes may be located in the abdominal cavity or inguinal canal. Major complications include an increased risk of testicular cancer (Sertoli cell tumors and seminomas) and endocrine disorders leading to feminization. Diagnosis is based on clinical examination and imaging modalities such as ultrasound. Orchiectomy, involving the removal of both the retained and normally descended testicles, is thought to be the gold standard for treatment. This method helps avoid complications and the transmission of the defect to offspring. According to Fédération Cynologique Internationale (FCI) standards, affected individuals should not be used for breeding or shows. Early detection, surgical intervention, and consistent exclusion from breeding programs are the primary strategies for reducing the incidence of this disorder in the canine population. Full article

Background/Objectives: Machine learning approaches are widely used in modern medical diagnostics, including cancer detection. The results can be significantly improved by aggregating individual measurements, and appropriate aggregation methods should be established. Methods: We applied various measurement aggregation strategies both before and after machine learning modeling to two datasets of X-ray diffraction images: human breast biopsy samples and canine claw samples. Two classifiers, Random Forest and Logistic Regression, were used to determine classification metrics: the area under the receiver operating characteristic curve (ROC-AUC) and balanced accuracy. Results: We found that all aggregation types improve classification metrics, with aggregation after modeling yielding better performance. Depending on the dataset and approach, either classifier can produce better results. For human breast samples, Random Forest with the logit aggregation strategy provides an ROC-AUC exceeding 0.9. For the canine dataset, both Random Forest with the logit aggregation strategy and Logistic Regression with the median of cancer probabilities achieve an ROC-AUC of about 0.85. Conclusions: We examined several simple, straightforward aggregation methods for patient diagnosis based on multiple measurements per patient and achieved significant improvements in classification metrics. Full article

Cancer is a leading cause of death in humans and dogs. Several erythrocyte and platelet characteristics (indices and morphology) have shown promise as indicators of metastasis in humans. Similar studies have not been performed in dogs. This study evaluated erythrocyte and platelet characteristics measured on the Advia 2120i in 59 tumor-bearing dogs with carcinoma or sarcoma. Tumor-bearing dogs with and without intracavitary hemorrhage that underwent complete post-mortem and histopathology examinations were compared to healthy age-controlled dogs. Carcinoma- and sarcoma-bearing dogs without hemorrhage were compared. All tumor-bearing dogs without hemorrhage or metastasis were compared to those with metastasis, and characteristics were evaluated as indicators of metastasis. Tumor-bearing dogs without intracavitary hemorrhage (n = 49) had decreased hematocrit (p = 0.002) and reticulocyte hemoglobin content (p = 0.022), and increase in anisocytosis (p = 0.002), polychromasia (p = 0.002), macrocytosis (p = 0.032), codocytes (p = 0.022), absolute reticulocyte count (p = 0.035), platelet concentration (p = 0.002), plateletcrit (p = 0.022), and platelet volume distribution width (p = 0.022) compared to healthy dogs (n = 20). In tumor-bearing dogs with intracavitary hemorrhage (n = 10), additional significant differences were reflective of acute hemorrhage. No difference in characteristics between carcinoma- and sarcoma-bearing dogs without hemorrhage was identified. After correction for multiple comparisons, no differences in erythrocyte or platelet characteristics were identified between tumor-bearing dogs without intracavitary hemorrhage and metastasis and those without metastasis. Significant differences in characteristics exist between tumor-bearing dogs and healthy dogs. Based on the limited number of dogs in this preliminary study, no red blood cell or platelet characteristics were associated with metastatic disease in tumor-bearing dogs without hemorrhage. Full article

Cancer remains the leading cause of death in domestic dogs. Conventional therapeutic approaches, including surgery, chemotherapy, and radiotherapy, frequently fail to achieve sustained remission or stabilization. Oncolytic virotherapy, a rapidly advancing therapeutic modality in human oncology, is emerging as a novel strategy in veterinary medicine. This systematic review summarizes current knowledge on the application of oncolytic viruses (OVs) in canine cancer treatment, focusing on their mechanisms of action, safety profiles, and clinical efficacy. We evaluate diverse OV platforms, including myxoma virus, reovirus, vesicular stomatitis virus, canine adenoviruses, vaccinia virus, Sendai virus, and Newcastle disease virus, across preclinical and clinical studies in dogs with various malignancies. While several OVs have demonstrated favorable tolerability and modest antitumor activity, key challenges such as pre-existing immunity, optimization of dosing regimens, and rational combination strategies remain to be addressed. This review emphasizes the translational significance of canine studies for both veterinary and human oncology, underscoring the critical need for rigorously designed clinical trials to refine virotherapy protocols and expand therapeutic options for canine cancer patients. Full article