Search Results (823)

Breast cancer is one of the most prevalent malignancies in women worldwide and the most common malignant tumor in unspayed female dogs, highlighting the comparative relevance of this disease across these species. The release of EVs is increased in mammary tumors compared to normal tissue, with the quantity generally correlating with the tumor’s histological grade and aggressiveness. EVs carry a varied molecular load, mainly composed of proteins, RNAs, including microRNAs (miRNAs), lipids, and nucleic acids. These contents reflect the cell of origin and are related to the tumor profile (adenoma, adenocarcinoma, or carcinoma). EVs influence biological processes such as cell proliferation, migration, and invasion, as well as interfere with the immune response, potentially favoring tumor growth, disease progression, and metastasis formation, since they act as intercellular messengers, modulating the tumor microenvironment. Despite substantial advances in research related to EVs in human breast cancer, there is still a significant lack of studies focused on veterinary oncology, especially regarding the association of EVs with CMTs. In this context, this review aimed to compile the evidence available to highlight the importance of EVs in CMTs in female dogs, especially as promising tools for innovative strategies in veterinary medicine. Full article

Breast cancer remains a leading cause of cancer-related mortality worldwide, highlighting the need for novel therapeutic strategies that selectively target tumor cells while minimizing systemic toxicity. Dietary ammonium hydroxide enhancement (AHE) has previously been shown to modulate metabolic pathways in animal studies. However, its potential as a localized anticancer therapy has not been investigated. In the present study, we evaluated the antitumor efficacy and systemic safety of NH₄OH using complementary in vitro and orthotopic breast cancer xenograft models. MDA-MB-231 breast cancer cells and non-tumorigenic MCF10A mammary epithelial cells were treated with increasing concentrations of NH₄OH (2.5–225 µM) to assess dose-dependent effects on cell proliferation, viability, and apoptosis. Following this, MDA-MB-231 cells were orthotopically xenografted into female athymic nude mice and treated by intratumoral injection with NH₄OH using a stepwise dose-escalation regimen (0.01%, 0.1%, and 0.5%; total volume of 20 μL per tumor divided between two injection sites) or phosphate-buffered saline (PBS). Differences between treatment groups of mammary tumors and kidney tissues were analyzed molecularly and histologically. NH₄OH significantly suppressed MDA-MB-231 cell growth and metabolic activity, with minimal effects on MCF10A cells, and induced apoptosis in MDA-MB-231 cells without detectable apoptotic induction in MCF10A cells. In vivo, although tumor volume only showed a non-significant downward trend, histological and molecular analyses demonstrated substantial alterations in tumor biology. NH₄OH treatment induced molecular changes consistent with an antitumor response, including increased Caspase-3 and p53 expression, reduced BCL2 and Ki-67 expression, and attenuation of TNFα, IL-6, and TLR4 inflammatory signaling. Furthermore, the tumor architecture in T-NH tumors displayed increased pale eosinophilic regions and reduced cellular density, suggestive of treatment-associated tumor tissue disruption. Histological analysis of kidney tissue showed no evidence of overt renal toxicity. Indeed, localized NH₄OH administration was associated with reduced renal inflammatory and apoptotic signaling, preserved renal morphology, and increased expression of the ammonia transporters RHBG and RHCG. Cross-sectional morphometric measurements showed decreased area for the distal convoluted tubules in NH₄OH-treated samples. Although this initial preclinical study was limited by a relatively small sample size, further studies are warranted to validate these findings and define the molecular mechanisms underlying NH₄OH-mediated antitumor activity. Collectively, these findings suggest that intratumoral NH₄OH modulates tumor metabolic, inflammatory, and apoptotic pathways associated with a less aggressive tumor phenotype while showing no overt molecular or histological evidence of renal injury, supporting further investigation as a localized metabolic intervention targeting molecular and histological drivers of breast cancer progression. Full article

Breast cancer (BC) is a heterogeneous disease influenced by genetic and regulatory mechanisms. Despite this, X-linked non-coding variants remain underexplored, particularly in admixed Latin American populations. Therefore, this study aimed to characterize the non-coding variant rs5945619 at Xp11.22 in Ecuadorian mestizo women with BC and to assess its potential regulatory effects on nearby genes through in silico cis-eQTL analysis. A prospective observational case series was conducted in 21 Ecuadorian mestizo women with histologically confirmed BC. Tumor DNA was extracted and analyzed using the Illumina TruSight Cancer Sequencing Panel. The rs5945619 variant was identified from sequencing data and compared with reference allele frequencies from dbSNP, ALFA, and the 1000 Genomes Project. Regulatory potential was assessed using RegulomeDB v2.2, and tissue-specific cis-eQTL associations were explored using GTEx. All 21 patients carried the genetic variant rs5945619 in a heterozygous state. The mean age at diagnosis was 54.5 ± 12.2 years, and invasive breast carcinoma of no special type was the predominant histological subtype. The T-allele frequency in the study cohort was 0.50, whereas Latin American reference populations showed higher frequencies ranging from 0.69 to 0.83. RegulomeDB assigned rs5945619 a rank of 1f and a functional score of 0.22, supporting its regulatory potential. GTEx analysis identified tissue-specific cis-eQTL signals, including LINC01496 upregulation in testis, NUDT11 and LINC01496 downregulation in prostate, and modest GSPT2 downregulation in mammary tissue. This study provides the first characterization of rs5945619 in Ecuadorian mestizo women with BC and suggests its role as a potential X-linked regulatory variant, requiring further validation. Although universal heterozygosity was observed, the small sample size, tumor-only design, and absence of a healthy control cohort prevent any causal, risk-factor, or tumor-driven selection inference. The in silico evidence supports a tissue-dependent regulatory model involving LINC01496 and NUDT11, mainly in prostate/testis, and a modest GSPT2 signal in mammary tissue. Therefore, breast cancer-specific eQTL analyses, functional validation, and larger ancestry-informed case–control studies are required to determine the biological and clinical relevance of this locus. Full article

CBL-B is an intracellular E3 ubiquitin ligase that acts as a T cell checkpoint by raising activation thresholds and limiting effector function. Here, genetic targeting of CBL-B enhances the performance of adoptively transferred T cells and CAR T cells under tumor microenvironment-like stress. In fully immunocompetent mouse models, Cblb deficiency or transient Cblb silencing improves control of MC-38 colon carcinoma and autochthonous mammary tumors, demonstrating that CBL-B restrains anti-tumor immunity. Cblb-deficient T cells show enhanced expansion and effector/effector-memory differentiation during an in vivo mixed lymphocyte reaction, confirming a cell-intrinsic brake function of CBL-B during sustained antigenic challenge. In a syngeneic Panc02-EpCAM model, Cblb-deficient anti-EpCAM CAR T cells show superior tumor control, enhanced infiltration, prolonged survival, and preserved effector function despite chronic antigen exposure and TGF-β. Mechanistically, Cblb targeting maintains granzyme B and IFN-γ production and is associated in vitro with increased GSDME-linked pyroptotic tumor cell death, consistent with features of immunogenic cell death. These findings extend previous CBL-B CAR T work from lymphocyte-deficient to immunocompetent settings and support CBL-B inhibition as a strategy to engineer CAR T cells that resist suppressive tumor microenvironments while promoting a more inflammatory mode of tumor killing. Full article

Estrogen receptor-positive breast cancer remains difficult to treat, driving the search for new therapeutic agents. Juncus effusus L., a medicinal plant rich in bioactive constituents, has shown preliminary anticancer activity, yet its efficacy in hormone-responsive tumor models in vivo has not been established. We evaluated the antitumor effects of the ethyl acetate sub-extract of J. effusus L. subsp. effusus in an N-methyl-N-nitrosourea (NMU)-induced rat mammary tumor model, assessing tumor burden, histopathology, and molecular markers. Thirty-six Sprague–Dawley rats were divided into six groups (n = 6): sham, control, reference, and three groups receiving the sub-extract at 100, 200, or 400 mg/kg. After NMU induction (50 mg/kg), treatment began once tumor volumes reached approximately 2000 mm³ and continued for eight weeks. The 200 mg/kg dose markedly reduced tumor volume relative to control (p < 0.0001) and lowered both ERα and PCNA expression (p < 0.001 and p < 0.0001). The 100 and 200 mg/kg groups also showed lower p53 and ERα mRNA levels than the other treatment groups. HIF-1α, though elevated in control tumors, declined only modestly and without statistical significance after treatment. These results indicate that J. effusus subsp. effusus, particularly at 200 mg/kg, suppresses proliferation and modulates ERα- and p53 expression, supporting its potential for further preclinical investigation. Full article

Background: Coronary artery bypass grafting (CABG) is the standard revascularization procedure, and the left internal mammary artery (LIMA) is the most widely used conduit owing to its long-term patency and favorable impact on survival. Although fibrosis and calcification are comparatively infrequent in internal mammary artery (IMA) grafts, progressive remodeling may still compromise patency. Tumor necrosis factor-α (TNF-α) is a pro-inflammatory cytokine implicated in vascular remodeling and calcification, whereas L-arginine, a precursor of nitric oxide, may exert vasoprotective effects. Aim: To investigate the effects of ex vivo TNF-α and combined TNF-α plus L-arginine treatment on the morphology, calcification, elemental composition, and biomechanical properties of human LIMA grafts. Patients and Methods: LIMA graft segments from 18 male CABG patients were allocated to one control group (G0) and two ex vivo treatment groups. Grafts were assessed using hematoxylin and eosin and Masson’s Trichrome staining under brightfield microscopy, using Alizarin Red S fluorescence staining to measure calcification, and by scanning electron microscopy with energy-dispersive spectroscopy (SEM/EDS) to assess ultrastructure and elemental composition. Scanning acoustic microscopy (SAM) was used to derive acoustic impedance as a label-free index of tissue stiffness. Results: TNF-α treatment was associated with increased acoustic impedance, consistent with graft stiffening, together with greater calcification signatures, whereas combined TNF-α and L-arginine treatment shifted impedance toward control-like values and showed more organized tissue architectures with reduced calcification. Conclusions: In this preliminary ex vivo model, L-arginine attenuated TNF-α-associated remodeling and stiffening of LIMA grafts, suggesting a potential role in supporting graft durability; larger, statistically powered studies with molecular validation are required to confirm these findings. 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

Background: The diversity of RNA isoforms plays a critical role in regulating the development and progression of human cancers. Our previous work has demonstrated that piR-2158 exerts antitumor activity in breast cancer by repressing IL11-STAT3 signaling. Methods: The isoforms of piR-2158 were analyzed using Sanger sequencing, quantitative real-time PCR (qRT-PCR), and Gene Expression Omnibus (GEO) dataset. Cell proliferation capacity was assessed using Cell Counting Kit-8 (CCK-8) assays and Ki67 immunofluorescence staining. Cell migration was evaluated using wound healing assays. Cancer cell stemness was analyzed using mammosphere formation assay, stemness marker detection, and ALDH activity assay. Results: We identified two types of piR-2158 isoforms in mammary tissues: a 31 nt long isopiR (designated as iso-piR-2158-L) and a 28 nt short isopiR (designated as iso-piR-2158-S). Predominant expression of iso-piR-2158-L was observed in normal mammary epithelial cells and adjacent non-tumor breast tissues, whereas it was significantly downregulated in TNBC cell lines and primary tumor tissues. We experimentally demonstrated that iso-piR-2158-L and iso-piR-2158-S exert distinct effects on TNBC cell proliferation, migration, and stemness, with iso-piR-2158-L showing significantly stronger antitumor effects than iso-piR-2158-S. Subsequent mechanistic studies revealed that iso-piR-2158-L suppresses IL11 expression more effectively, compared to iso-piR-2158-S. Conclusions: Our findings reveal a piRNA isoform-based regulatory pathway that may be involved in regulating pathological transformation, tumor initiation, and progression in TNBC. Full article

Background: Routine use of the chorioallantoic membrane (CAM) tumor model in nuclear imaging studies is hampered by small tumors, embryonic movements and laborious volume-restricted intravenous tracer/drug administration. We sought a workaround by using fast-growing tumors, high-resolution autoradiography and non-intravenous tracer administration. Methods: Dekalb White chicken eggs were grafted with C3H mammary carcinoma fragments or MOC2 oral squamous cell carcinoma fragments from donor mice. The tumor uptake of ¹⁸F-fluorodeoxyglucose (FDG) following in-yolk-sac injection, dripping after CAM scoring or allantoic cavity injection was evaluated using positron emission tomography (PET) and autoradiography. Using in-yolk-sac injection, eggs were administered different tracer mixtures, namely (1) pimonidazole (hypoxia-marker), FDG and ¹⁴C-2-deoxyglucose (¹⁴C-2DG), (2) pimonidazole, FDG and ¹⁴C-acetate or (3) pimonidazole, the hypoxia-selective tracer ¹⁸F-fluoroazomycin-arabinoside (FAZA) and ¹⁴C-2DG. For comparison, tumor-bearing mice were administered FDG/¹⁴C-acetate/pimonidazole. Gross tumor uptake was evaluated using PET. Tumor cryosections were analyzed using dual-tracer autoradiography. Complementary autoradiograms were co-registered, covered by a square grid (0.5 × 0.5 mm). Pearson correlation coefficients (PCC) were calculated from scatterplots. Results: C3H tumors reached a mean weight (with 95% confidence interval) of 0.32 g (0.28–0.37 g), while for MOC2, it was 0.19 g (0.09–0.29 g). In-yolk-sac tracer injection was simple and effective, producing high tracer uptake and contrast 3 h post-administration. Spatial tracer overlap (PCC) was: FDG vs. ¹⁴C-2DG, 0.95–0.97; FAZA vs. ¹⁴C-2DG, 0.71–0.79 and FDG vs. ¹⁴C-acetate, 0.26–0.84 (0.15–0.76 in mice). Pimonidazole revealed tumor hypoxia. Conclusions: Direct-grafting from donor mice generated larger tumors than previously reported. In-yolk-sac tracer administration was practical and allowed larger injected volumes. Autoradiography revealed that: (1) FDG and ¹⁴C-2DG can be used interchangeably, (2) ¹⁴C-2DG was elevated in FAZA-positive areas, suggesting that in some tumors FDG-PET may provide information on the intratumoral distribution of hypoxic areas, and (3) FDG and ¹⁴C-acetate showed variable overlap. We conclude that in-yolk-sac tracer injection and autoradiography simplify and optimize CAM-based nuclear imaging research. Full article

Background: Comparative oncology uses naturally occurring cancers in companion animals to study tumor biology and therapeutic responses relevant to human cancer. Spontaneous feline tumors are increasingly recognized as useful comparative models because they arise in immunocompetent hosts, develop under shared environmental exposures, and can reproduce selected clinical, histopathologic, molecular, and therapeutic features of human malignancies. Methods: This review compares feline oral squamous cell carcinoma (FOSCC) with human head and neck squamous cell carcinoma (HNSCC), and feline mammary carcinoma (FMC) with human breast cancer, emphasizing shared pathologic, molecular, tumor microenvironment, and therapeutic features. Results: Recent immunohistochemical, genomic, transcriptomic, and biomarker studies have identified shared features between feline and human cancers. FOSCC resembles human HNSCC through aggressive local invasion, histologic features, therapeutic resistance, and recurrent alterations of TP53, MYC, and PTEN. FMC shows strong overlap with aggressive human triple-negative breast cancer, including reduced hormone receptor expression, recurrent TP53, PIK3CA, and CXCL12/CXCR4 signaling alterations, and tumor microenvironment features involving immune-checkpoint, inflammatory, and angiogenic pathways. FOSCC clinical trials and emerging clinical investigations into FMC treatments further support the use of cats for translational therapy evaluation. Conclusions: FOSCC and FMC are promising comparative oncology models for human HNSCC and aggressive breast cancer, respectively. Future multicenter studies incorporating standardized tumor classification and grading, predefined stratification criteria, and clinically meaningful endpoints will be essential to strengthen their translational value. Full article

Oncolytic virotherapy offers a promising avenue for solid tumor treatment, yet single-agent approaches are frequently limited by insufficient tumor lysis and inadequate immune activation. Here we report that combined therapy with two recombinant variants of the oncolytic vaccinia virus, armed with either herpes simplex virus thymidine kinase (VV-HSVtk) or the interleukin 15 receptor subunit alpha (VV-mIL15Rα), leads to enhanced cytotoxicity and immune stimulation in a murine mammary adenocarcinoma model (4T1). In vitro, VV-HSVtk exhibited dose-dependent cytotoxicity markedly potentiated by ganciclovir (GCV) through HSVtk-mediated phosphorylation into a cytotoxic nucleoside analog, and co-culture of VV-infected tumor cells with donor-derived NK cells further increased oncolytic efficiency. In vivo, combined treatment with VV-HSVtk, VV-mIL15Rα, and GCV resulted in significant tumor regression and extended survival relative to monotherapy controls in 4T1 syngeneic mice. Histological examination revealed increased lymphocytic infiltration at tumor sites and absence of hepatic or splenic toxicity. Together, these data indicate that integrating direct viral cytotoxicity, HSVtk/GCV-mediated suicide gene therapy, and IL-15-pathway-targeted immunomodulation within an oncolytic vaccinia platform can improve antitumor efficacy in a stringent breast cancer model. 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