Veterinary and comparative oncology最新文献

Steroids provide rapid clinical improvement in dogs with multicentric diffuse large B-cell lymphoma (DLBCL). However, their use before chemotherapy can induce chemoresistance and compromise diagnostic yield due to increased apoptotic cells. This retrospective study assessed the impact of steroid dose and duration on flow cytometry (FC) diagnostic yield and clinical outcomes in dogs with DLBCL subsequently treated with chemotherapy. Of 273 dogs diagnosed with DLBCL between January 2014 and March 2024, 67 (24.5%) received steroids before treatment (median dose: 1 mg/kg, range: 0.5-3 mg/kg; median duration 8 days, range: 1-1080 days). In 94.0% of cases, steroids were administered for lymphoma management. All dogs received CHOP-based chemotherapy, and 38 (56.7%) also received immunotherapy. Median time to progression (TTP) and lymphoma-specific survival (LSS) were 143 days (95% CI: 111-175) and 196 days (95% CI: 152-240), respectively. Steroid dose, duration, and cumulative dose had no significant impact on TTP or LSS. However, the addition of immunotherapy was associated with longer LSS (p = 0.023). FC diagnostic yield was lower in steroid-treated dogs compared to 67 non-pre-treated dogs (p = 0.042). However, within the pre-treated group, neither dose nor duration impacted diagnostic yield (p > 0.05). In addition, TTP (p = 0.003) and LSS (p < 0.001) were significantly longer in non-pre-treated dogs compared to steroid-treated dogs. These findings suggest that the detrimental effects of upfront steroids are independent of dose or duration. Given their potential to compromise diagnosis and treatment outcomes, corticosteroids should be used with caution and reserved for cases where clinical benefits clearly outweigh the risks.

Radiation therapy (RT) is the treatment of choice for canine intracranial gliomas. Recently, modern advanced radiation techniques, including intensity modulated RT (IMRT) and volumetric modulated arc therapy (VMAT), have become widely available in veterinary medicine. However, the glioma-specific therapeutic outcomes of patients treated with modern RT remain unclear. This study aimed to describe survival outcomes and tumour response and to identify whether any treatment, clinical, and imaging factors were predictive of prognosis in dogs with intracranial gliomas treated with definitive-intent IMRT alone. Medical records of dogs with presumed intracranial gliomas that underwent definitive-intent IMRT were retrospectively reviewed. Fifty-five dogs were included. Amongst them, 29 and 26 underwent fractionated RT (FRT) and stereotactic RT (SRT), respectively. In the 44 dogs that underwent follow-up magnetic resonance imaging (MRI), the overall measurable response rate was 77.3%. Clinical improvement was observed in 92% of the dogs. Local tumour regrowth and drop metastases were observed in 17 (30.9%) and 10 dogs (18.2%), respectively. The median overall survival, disease-specific survival, and progression-free survival were 432, 670, and 441 days, respectively. Seven dogs (12.7%) died during RT or within 6 weeks. There was no statistically significant difference in the survival times between FRT and SRT. In the multivariate analysis, poor performance status, tumour location in the diencephalon, and fluid-attenuated inversion recovery heterogeneity were significantly associated with shorter survival times. These findings suggest that definitive-intent RT results in tumour shrinkage and prolonged survival (432 days) with minimal radiation toxicity regardless of the RT protocol used. Performance status and MRI findings can be useful for predicting prognosis.

As computed tomography (CT) becomes more commonly used in clinical practice for staging and surgical planning of dogs with adrenal tumours, there remain few reports on CT characteristics of malignant adrenal tumours and none that correlate imaging findings with survival. This retrospective study attempts to evaluate preoperative CT characteristics that are associated with malignancy and those that may be associated with shorter survival in dogs with surgically addressed adrenal tumours. CT scans performed at a single tertiary care facility were examined by a single blinded radiologist, and the findings were correlated with histopathology results as well as short- and long-term survival. A total of 226 adrenal tumours were assessed from 201 individual patients. The overall median survival time for adrenal tumours was 671 days. Dogs undergoing unilateral versus bilateral adrenalectomies had longer survival, with a median survival time of 697 versus 623 days (p = 0.02). Consensus histopathologic diagnosis as malignant versus benign was not associated with a significantly shorter survival time, 952 versus 1514 days, p = 0.04, q = 0.25. No CT features were associated with shortened long-term survival times on multivariate analysis. Excluding deaths within 24 h of surgery, splenectomy was predictive for hazard of death and was retained on multivariate analysis p = 0.03, HR = 2.33. Age (p = 0.0001, HR = 1.23) and concurrent ureteronephrectomy at the time of adrenalectomy (p = 0.042, HR = 2.45) were shown to affect long-term survival and were retained on multivariate analysis. This information may be useful when prognosticating outcomes for pet owners presenting for surgery.

The subtle sequence diversity and mutually exclusive expression patterns of T cell receptor beta chain constant genes, TRBC1 and TRBC2, in mature human T cells, provide the basis for immune-targeting strategies designed to eliminate clonally expanded malignant T cells while sparing a subset of normal T cells capable of maintaining immunocompetence. The evolutionarily conserved gene arrangement and regulation of TRBC loci in mammals make these genes attractive targets for translational immune-targeting strategies in companion species, including dogs. However, available TRBC sequence data relevant to common dog breeds remains limited. In this study, we investigated the sequence diversity and mRNA expression profiles of canine TRBC1 and TRBC2 genes in peripheral blood mononuclear cell (PBMC) samples representing 14 different dog breeds, and in six established canine haematopoietic cell lines of both T-cell and non-T-cell origin (i.e., B and NK cell lines). Our analysis uncovered a previously unreported variation in the TRBC1 sequence encoding the transmembrane region but found no sequence diversity in the extracellular domain of TRBC1 and TRBC2. A nearly equal mRNA expression of TRBC1 and TRBC2 was consistently observed in bulk samples of canine PBMCs across all breeds, in contrast to canine cell lines, which exhibited a more skewed expression profile. Unexpectedly, germline mRNA expression of TRBC was present in some (i.e., CLB70, GL1) but not other (i.e., CLBL1) canine cell lines of B cell origin. In conclusion, our findings indicate that the fully conserved amino acid sequence in the extracellular domain of canine TCR beta chain variants presents a challenge for the development of differential therapeutic antibodies. Additionally, the presence of germline TRBC transcripts in certain canine B-cell neoplasms, but not others, may provide additional insights into the developmental stages from which these neoplasms originate.

Urothelial carcinoma (UC) in pet dogs resembles muscle-invasive UC in people. Human UC is strongly associated with aromatic amine exposures, either in tobacco smoke or through occupational exposures. However, the role of aromatic amines in canine UC is not understood. Urine from dogs diagnosed with UC (n = 37) and unaffected controls (n = 36), collected in a previous case-control study, were analysed for 12 aromatic amines. Eleven aromatic amines were (o-anisidine, p-toluidine, o-toluidine, 4-chloroaniline, 2,6-dimethylaniline, 3,5-dimethylaniline, aniline, 2-napthylamine, p-cresidine, 4,4'-methylenedianiline, and 4-ethoxyaniline) detected in most urine samples; 4-aminobiphenyl was detected in only three dogs. Urinary concentrations of o-toluidine were significantly higher in cases (median 0.16, range 0.03-2.00 ng/mg creat) versus controls (median 0.11, range 0.02-0.42 ng/mg/creat; p = 0.017), but differences were modest with substantial overlap between groups, and we did not control for multiple comparisons. Urinary o-toluidine was most strongly correlated with urinary aniline, which reached the highest median concentrations overall (1.65 ng/mg creat or 2.60 ng/mL). Total molar aromatic amine urinary exposures were not different between pet dogs living in metropolitan versus rural areas using USDA Rural-Urban Continuum codes in this small sample size. Follow-up studies are indicated to establish the genotoxic thresholds for o-toluidine and aniline in canine urothelial cells and determine whether some pet dogs are exposed to genotoxic urinary concentrations of these aromatic amines in vivo.

Mitotic count (MC) is a well-established prognostic factor in many canine malignancies. While standardisation efforts have improved inter-pathologist agreement regarding the morphology of mitotic figures and the size of the counting area, the selection of the tumour region for MC assessment remains to be standardised. This study aimed to evaluate the spatial distribution of the most proliferative areas in selected canine tumour types, using Ki67 immunohistochemistry, to identify optimal candidate regions for MC assessment. Tumour types analysed included melanomas, cutaneous mast cell tumours (cMCT), canine mammary carcinomas (CMC) and soft tissue sarcomas (STS). Using image analysis, Ki67 density maps were generated from digital slides and classified according to their distribution pattern (focal/multifocal or diffuse) and location within the tumour (central, peripheral or scattered). A total of 202 cases were included: 43 melanomas, 30 cMCTs, 42 CMCs and 87 cSTSs. The vast majority of tumours (92.6%) exhibited a multifocal hotspot distribution. Peripheral hotspot localisation was predominant in 55% of cases, particularly in cMCTs (73.3%) and melanomas (76.7%). In contrast, cSTSs more frequently showed a scattered hotspot pattern (60.9%) (χ² = 41.9; p < 0.001). CMCs had a higher proportion of centrally located hotspots (16.7%). These findings suggest that pathologists should focus on peripheral tumour regions when assessing MC in cMCTs and melanomas. Both central and peripheral regions should be considered in CMCs, while a more extensive, comprehensive evaluation may be required in STSs. The observed association between tumour histotype and proliferation pattern likely reflects inherent biological differences among the tumour types studied.

Human enteropathy-associated T-cell lymphoma (EATL) is a rare primary aggressive intestinal T-cell lymphoma associated with celiac disease and is considered to be a neoplasm of intraepithelial lymphocytes (IELs) with an innate lymphoid cell (ILC)-like immunophenotype. The lack of an animal model has delayed the elucidation of its pathogenesis. In dogs, the histopathological and immunophenotypic features of intestinal large T-cell lymphoma (ILTCL) are similar to EATL; however, its cell of origin remains unclear. We herein performed detailed immunophenotyping, an RNA expression analysis of selected genes, and gene mutation analysis of 54 cases of ILTCL, including 27 with fresh frozen samples available and 21 of intestinal small T-cell lymphoma (ISTCL) in dogs. Canine ILTCL was characterised by the expression of cytotoxic granules (53/54) and frequent absence of CD4/CD8 (26/27) and T-cell receptors (14/27). The mRNA expression of CD103 (25/35) and NKp46 (15/35) was detected in ILTCL by RNA in situ hybridisation. The gene mutation analysis showed mutations in NFKBIA (ILTCL, 31/54; ISTCL, 10/21), including truncating mutations (ILTCL, 11/54; ISTCL, 3/21). Mutations in STAT3 SH2 were less frequent (ILTCL, 13/54; ISTCL, 3/21) and the hotspot JAK1 mutation of human EATL was not detected. Immunohistochemistry for p-Stat3 showed STAT3 pathway activation in ILTCL cases. These results suggest that canine ILTCL is also a neoplasm of IEL with an ILC-like immunophenotype and STAT3 pathway activation, and loss-of-function mutations in NF-κB pathway inhibitors are associated with its neoplastic changes. Therefore, canine ILTCL has potential as a valuable model for investigating the pathogenesis of EATL.

Cytological evaluation of regional lymph nodes (LNs) is routinely used for staging canine mast cell tumours (MCTs), but its diagnostic accuracy requires further validation. This multicentre retrospective study compared Krick's cytological criteria with Weishaar's histopathological classification for detecting LN metastasis in canine MCTs, and evaluated whether cytology with modified Wright-Giemsa stain (WGS) could outperform routine haematoxylin-eosin (H&E) histology in identifying early metastatic LNs. Paired cytological and histopathological evaluations were performed on 65 LNs from 52 dogs undergoing lymphadenectomy, with toluidine blue staining (TBS) applied when metastasis was not evident on H&E. Cytology samples were classified using Krick's criteria (normal/reactive, possible, probable, certain metastasis). Histopathology was graded according to Weishaar's system (HN0-HN3). Diagnostic performance was assessed for three cytologic positivity groups (G): G1 (certain), G2 (certain/probable), and G3 (certain/probable/possible). Cytology detected 87.5% of early (HN2) and 95% of overt (HN3) metastases, outperforming H&E (25% and 85%, respectively). G1 showed moderate sensitivity (75%) but high specificity (93.1%), positive predictive value (93.1%), and positive likelihood ratio (10.5). G3 yielded the highest sensitivity (91.7%) but the lowest specificity (62.1%), with a negative predictive value of 85.7% and a negative likelihood ratio of 0.13. ROC analysis revealed notable diagnostic performance with Kappa values indicating moderate to substantial agreement between cytology and histopathology. Our results validate cytology with WGS as a reliable tool for LN staging in MCTs, outperforming routine H&E histology in the detection of early metastatic LNs. However, the 'possible' and 'probable' categories should be interpreted cautiously. TBS is essential for accurate nodal histopathological assessment. Definitive staging should integrate histopathology and advanced nodal mapping techniques to optimise sentinel LN identification.

Vascular endothelial growth factor receptor 2 (VEGFR2) is a key target for anti-angiogenic oncotherapy, as inhibiting this receptor on tumour vasculature slows tumour development and enhances drug- and immune infiltration, improving therapy outcome. Although VEGFR2 is primarily expressed on endothelial cells (ECs), it is also found on neoplastic cells in both humans and dogs, including canine malignant melanoma (CMM). In this study, we compared current methods for assessing VEGFR2 expression in CMM and healthy tissues to elucidate the targets of anti-VEGFR2 therapy in canines. VEGFR2 protein expression was analysed using various anti-VEGFR2 antibodies for immunohistochemistry, and mRNA expression was analysed using RT-PCR. Surprisingly, a marked difference in the detection of VEGFR2 was observed between the anti-VEGFR2 antibody clones used, despite recognition of the same sequences. Supported by additional Western blot and confocal fluorescence microscopy analysis, we observed two distinct staining patterns: a specific pattern predominantly labelling ECs and a more nonspecific pattern predominantly labelling non-ECs, including neoplastic melanocytes. Notably, the more specific pattern demonstrated significantly more VEGFR2 expression in ECs within CMM. These findings indicate that the interpretation of VEGFR2 expression on neoplastic cells is highly dependent on antibody specificity, leading to potential overestimation in some studies. We therefore suggest that anti-VEGFR2 therapy primarily targets the tumour vasculature rather than the tumour cells. This highlights the need to reconsider the aims of anti-VEGFR2 therapies in companion animals.

Feline mammary tumours represent the third most common malignancy in cats, with limited evidence-based tools available for risk assessment and screening guidance. Traditional veterinary approaches rely on subjective clinical judgement, lacking quantitative risk stratification methods that could optimise preventive care delivery. To develop and validate the first comprehensive machine learning-based risk prediction system for feline mammary tumours, providing evidence-based clinical decision support for veterinary practice. We developed a comprehensive synthetic dataset of 4399 feline cases spanning 2002-2022, systematically calibrated against real-world epidemiological data from published literature. The synthetic data incorporated demographic, clinical, reproductive, and environmental variables that precisely replicated actual epidemiological relationships. Five machine learning algorithms (Random Forest, XGBoost, Neural Network, SVM, Logistic Regression) were trained and combined using soft voting ensemble methodology. Model performance was evaluated using area under the curve (AUC), calibration metrics, and clinical utility measures. The ensemble model achieved excellent discrimination capability (AUC = 0.888, 95% CI: 0.873-0.903) with 80.5% accuracy, 85.7% sensitivity, and 76.0% specificity. Risk stratification demonstrated clear clinical utility: low-risk cats (< 30% probability) had 12.4% tumour prevalence, while very high-risk cats (> 80% probability) showed 89.5% prevalence. The machine learning approach substantially outperformed traditional assessment methods, showing 64.8% improvement in discriminative ability and a 163% increase in net clinical benefit. This study establishes the first validated machine learning-based clinical decision support system for feline mammary tumour risk assessment. The risk stratification approach enables personalised screening recommendations while optimising resource allocation, potentially transforming preventive veterinary oncology practice.