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Necrosis is a common finding in human and animal neoplasms. The percentage of tumor necrosis is included in tumor grading schemes in veterinary oncology; however, evaluation methods are often overlooked. Different studies have assessed the prognostic value of tumor necrosis in feline mammary tumors with contradictory results, which could be related to methodologic variability. In this study, a comprehensive evaluation of tumor necrosis in feline mammary tumors (FMTs) was conducted, by applying a semi-quantitative and a quantitative methodology for assessing necrosis. The interobserver agreement, the relationship with clinicopathological characteristics and the prognostic value of necrosis were analyzed in 154 FMT cases. Although subjectivity in the assessment of necrosis existed, an almost perfect agreement (weighted quadratic k = 0.851) between two observers was obtained. Furthermore, there was a significant positive correlation between the semi-quantitative and quantitative methods. Necrosis was more common and more extensive in malignant tumors than in their benign counterparts. Despite the non-significant results in the survival analysis, extensive necrosis was significantly associated with aggressive clinicopathological features, such as higher histological grade, high mitotic count and lymphovascular invasion. Our results support the potential relevance of necrosis in FMT.

Background: Lymphomas are the most common hematopoietic neoplasms in dogs and represent a heterogeneous group, as occurs in humans. Considering the role of dogs as models of human lymphomas and the geographical correlation of the cases of canine and human lymphoma, it is important to continuously assess the epidemiological distribution of lymphoma subtypes in dogs. Aim: The aim of this study was to provide a survey of canine lymphoma subtypes diagnosed from 2005 to 2016 in the academic veterinary pathology laboratory of the University of Porto. Methods: A total of 75 canine lymphomas diagnosed by histopathology in the Porto district were included. All cases were immunophenotyped by CD3 and PAX5, classified according to the current classification WHO, and coded with Vet-ICD-O-canine-1. Results: Mixed breed dogs were most common (28%), followed by Cocker Spaniels (12%), Boxers (9%), and Labrador Retrievers (6%). The mean age was 9.2 years (SD=3.3) (10.7 years for small, 8.9 years for medium and large, and 5.7 years for giant breed dogs, p [Open Vet J 2023; 13(4.000): 443-450]

Abstract Over the last decades, canines have experienced a marked increase in their lifespan, mirroring human populations. Several authors have pointed out the domestic dog as a suitable animal model for geropathology translational research. The aim of this study is to assess age-related morbidities and mortality in a population of 269 elderly canines (130 males and 139 females) submitted to necropsy. The organic systems exhibiting the higher number of age-related morbidities were the reproductive, cardiovascular and urinary systems and, in females, also the mammary gland. The prevalence of cardiovascular and urinary disease was significantly higher in males and mammary lesions were exclusively found in females. Urinary disease was more frequent in small breeds dogs, while peritoneum and male genital morbidities were significantly higher in larger breeds. Hyperplastic and degenerative lesions were common morbidities found in this elderly dog population. The main cause of death was neoplasia, which accounted for almost half of the deaths. Cardiovascular and urinary pathology also emerged as a frequent cause of mortality. These findings partially parallel data obtained for human species, displaying cancer and cardiovascular pathology as major causes of disease and death in elderlies. Our data reinforce the potential of the domestic dog for further translational investigations on gerontology, meeting the concept of One Health.

Abstract Background Cutaneous neoplastic diseases are the most and second-most frequently reported tumors in male and female dogs, respectively. The aims of this study were to report the occurrence of canine cutaneous tumors in a pathology laboratory located in Northern Portugal between 2014 and 2020, and to characterize and categorize the anatomical locations, breed, age, and sex of the animals affected with different types of neoplasms. Results Throughout the 7-year study, 1,185 cases were diagnosed as cutaneous tumors, with 62.9% being classified as benign, and 37.1% as malignant. Mast cell tumors (22.7%) were the most frequently diagnosed tumor type, followed by benign soft tissue tumors (9.7%), sebaceous gland tumors (8.1%), vascular tumors (7.9%) and soft tissue sarcomas (7.6%). Cutaneous tumors commonly exhibited multicentric occurrence (14.6%) followed by single occurrence in hindlimb (12.1%), forelimb (8.6%), buttock (7.1%), abdominal (6.5%) and costal (5.2%) areas. The odds of developing cutaneous neoplasia were higher with increasing age (p

Abstract Background The aetiology of pulmonary alveolar microlithiasis (PAM) in animals is still unknown. In humans, this pulmonary disorder is a rare autosomal recessive disorder triggered by a mutation in the gene SLC34A2, which causes deposition and aggregation of calcium and phosphate in the pulmonary parenchyma with formation of microliths. Although histopathological examination is required for a definite diagnosis, in humans, imaging modalities such as computed tomography can demonstrate typical patterns of the disease. This is the first description of the computed tomographic (CT) features of a histologically confirmed PAM in dogs. Case presentation The following report describes a case of a 7-year-old female Boxer dog evaluated for paroxysmal loss of muscle tone and consciousness with excitement. The main differential diagnoses considered were syncope, seizures, and narcolepsy-cataplexy. The results of the complete blood count, serum biochemistry panel, urinalysis, arterial blood pressure, echocardiography, abdominal ultrasound, Holter monitoring, and ECG were all within normal limits. Additional exams included thoracic radiographs, head and thorax CT, bronchoalveolar lavage (BAL), and CT-guided cytology. Thoracic radiographs revealed micronodular calcifications in the lungs, with sandstorm appearance. Computed tomography of the thorax showed the presence of numerous mineralized high-density agglomerates of multiple sizes throughout the pulmonary parenchyma, a reticular pattern with ground glass opacity and intense mineralized fibrosis of the pleural lining. Head CT was unremarkable. BAL and CT-guided cytology were inconclusive, but imaging features strongly suggest the diagnosis of PAM, which was histologically confirmed after necropsy. Conclusions This case report contributes to the clinicopathological and imaging characterization of pulmonary alveolar microlithiasis in dogs. In this species, the diagnosis of PAM should be considered when CT features evidence a reticular pattern with ground glass opacity and the presence of an elevated number and size of calcifications.

The role of HER2 in canine mammary tumors is not completely elucidated, and the contradictory results published so far may be, in part, explained by the genetic variability recognized in the canine HER2 gene. Single nucleotide polymorphism (SNPs) in HER2 were recently associated with less aggressive canine mammary tumor histotypes. This study assesses the relationship between SNPs rs24537329 and rs24537331 in canine HER2 gene and clinicopathological characteristics and outcome of mammary tumors in a group of 206 female dogs. Allelic variants were observed in 69.8% and 52.7% of the dogs for SNP rs24537329 and rs24537331, respectively. Our results demonstrated that SNP rs24537331 was associated with decreased tumoral necrosis (HR: 3.09; p = 0.012) and with longer disease-specific overall survival (HR: 2.59; p = 0.013). However, no statistically significant associations were found between SNP rs24537329 and the tumors’ clinicopathological characteristics or survival. Our data suggest that SNP rs24537331 may have a protective effect in canine mammary tumors, allowing the identification of a subgroup of animals prone to develop less aggressive forms of the disease. This study emphasizes the importance of the genetic tests associated with clinical images and histological examinations when assessing CMT outcomes.

Terrestrial domestic animals are exposed to microplastics, therefore, contaminating the food chain, in the case of livestock, or acting as sentinels for human exposure, in the case of companion animals. The aim of this review was to address the importance of terrestrial domestic animals on human exposure to microplastics. Animal products may already show some microplastics contamination, which may occur during their lifetime, possibly also compromising productivity, and during processing, originating from equipment and packaging. Moreover, release of microplastics in animal feces (or manure) leads to the contamination of agricultural fields, with possible impacts and internalization in plants. Therefore, microplastics pose a threat to food security, compromising food productivity, and food safety, by being a foreign material found in animal products. Conversely, in urban environments, companion animals (cats and dogs) may be relevant sentinels for human exposure. While oral exposure may vary in pets compared to humans, due to indiscriminate ingestion and chewing or licking behaviors, airborne exposure is likely to be a good indicator for human exposure. Therefore, future studies should address the importance of terrestrial domestic animals for human exposure of microplastics, both in the food chain and as sentinels for environmental exposure.

Abstract Background Estrogens are essential for the development and proper function of several hormone-dependent organs. There are, however, several lines of evidence associating estrogens with mammary carcinogenesis. A marked individual genetic variability concerning estrogens biosynthesis, metabolism and mechanism of action was recognized and associated with human breast cancer susceptibility, clinical features and progression. Although some genetic variations in canine ESR1 gene were reported, their influence in clinicopathological features and progression of canine mammary tumors has not been fully evaluated. This study aims to assess the influence of SNPs in ESR1 gene (rs397512133, rs397510462, rs851327560, rs397510612, rs852887655, rs852684753 and rs852398698) in canine mammary tumors characteristics and progression. A group of 155 non-neutered bitches with mammary tumors was included in the study. Follow-up information was assessed 24 months after surgery. Results Genetic profiles associated with a later onset of mammary tumors and less aggressive clinicopathological features, namely smaller tumor size (≤ 3 cm) with extensive tubular differentiation and low canine-adapted prognostic index (vet-NPI), were identified in this study. Conclusions Our data suggest that the ESR1 genetic profile may help on the decision regarding the selection of individual tailored preventive measures against canine mammary tumors development, such as early neutering.

Companion animals living in urban areas are exposed to environmental contaminants, which may include microplastics. A preliminary study was conducted by collecting postmortem samples from the internal tissue (lungs, ileum, liver, kidney, and blood clots) of 25 dogs (Canis familiaris) and 24 cats (Felis catus) living in an urban environment in Porto metropolitan area, Portugal. Suspected microplastics were found in 80 samples from 35 animals (18 cats and 17 dogs), often occurring in more than one tissue of the same animal (71.4%), primarily under small sizes (50.3% as 1–10 µm). Micro-Raman spectroscopy confirmed a fraction of particles as common polymer types (e.g., polyethylene terephthalate). However, the number of particles was very low. This study highlights the possibilities of the internalization and distribution of microplastics in the internal tissues of terrestrial vertebrates.

The animal cancer burden is essential for the translational value of companion animals in comparative oncology. The present work aims to describe, analyze, and compare frequencies and associations of tumors in dogs and cats based on the Animal Cancer Registry created by Vet-OncoNet. With 9079 registries, regarding 2019 and 2020, 81% (n = 7355) belonged to dogs. In comparison, cats have a general one-year right advance in the mean age of cancer diagnosis compared to dogs. The multivariate topography group analysis shows a distinct pattern between the two species: dogs have higher odds of cancer in the genito-urinary system, spleen, soft tissue tumors and skin, while cats show higher odds for tumors in the eyes, digestive organs, nasal cavity, lymph nodes, bones and mammary glands. Regarding morphologies, dogs are overrepresented in mast cell tumors (MCT), melanomas, and hemangiosarcomas. While cats are overrepresented in fibrosarcomas, lymphomas (T and B-cell), in malignant mammary tumors, and squamous cell carcinoma (SCC). Females have greater odds only in the mammary gland, with males having greater odds in six of twelve topographies. This study is the first outcome of continuous animal cancer registration studies in Portugal.

Pd2Spm is a dinuclear palladium(II)-spermine chelate with promising anticancer properties against triple-negative breast cancer (TNBC), a breast carcinoma subset with poor prognosis and limited treatment options. The present study evaluated the in vitro and in vivo anticancer effects of Pd2Spm compared to the reference metal-based drug cisplatin. Triple-negative breast cancer MDA-MB-231 cells, non-cancerous MCF-12A breast cells and chorioallantoic membrane (CAM) assay were used for antiproliferative, antimigratory and antiangiogenic studies. For an in vivo efficacy study, female CBA nude mice with subcutaneously implanted MDA-MB-231 breast tumors were treated with Pd2Spm (5 mg/kg/day) or cisplatin (2 mg/kg/day) administered intraperitoneally during 5 consecutive days. Promising selective antiproliferative activity of Pd2Spm was observed in MDA-MB-231 cells (IC50 values of 7.3–8.3 µM), with at least 10-fold lower activity in MCF-12A cells (IC50 values of 89.5–228.9 µM). Pd2Spm inhibited the migration of MDA-MB-231 cells, suppressed angiogenesis in CAM and decreased VEGF secretion from MDA-MB-231 cells with similar potency as cisplatin. Pd2Spm-treated mice showed a significant reduction in tumor growth progression, and tumors evidenced a reduction in the Ki-67 proliferation index and number of mitotic figures, as well as increased DNA damage, similar to cisplatin-treated animals. Encouragingly, systemic toxicity (hematotoxicity and weight loss) observed in cisplatin-treated animals was not observed in Pd2Spm-treated mice. The present study reports, for the first time, promising cancer selectivity, in vivo antitumor activity towards TNBC and a low systemic toxicity of Pd2Spm. Thus, this agent may be viewed as a promising Pd(II) drug candidate for the treatment of this type of low-prognosis neoplasia.

Triple-negative breast cancer (TNBC), a poor survival cancer has high resistance to therapy, with low-drug efficacy. Adenosine is present in high concentrations in the tumor microenvironment. Recently, adenosine was found to sensitize ovarian cisplatin-resistant cancer. This work aims at addressing if adenosine can sensitize TNBC resistance to platinum drugs. Concomitant or preincubation of adenosine with cisplatin or carboplatin induced cell proliferation in TNBC cisplatin-sensitive (MDA) and -resistant (MDA/R) cells (using Lionheart-FX microscope). Phosphorylation of the ERK or NF-κB pathways and cAMP production were evaluated (AlphaScreen assays). Data were analyzed with a one-way ANOVA t-test. Results: concomitant or preincubation of adenosine (300, 600, 700 µM) with cisplatin reduced resistance in MDA/R cells, with proliferation levels approaching those observed in MDA cells. In MDA cells, endogenous and exogenous adenosine have no effect over ERK phosphorylation; in MDA/R cells, exogenous adenosine lowers ERK phosphorylation. NF-κB phosphorylation was induced by A3R and A2BR tonic activation in MDA and MDA/R cells, respectively, increasing survival—exogenous adenosine inactivates this. Tonic cAMP production was altered in MDA and MDA/R cells, revealing inhibitory and stimulatory effects in cAMP production by A1R and A2BR, respectively, in MDA/R cells. In contrast, exogenous adenosine revealed that adenosine receptors in MDA cells contribute differently while in MDA/R cells all receptor subtypes have a similar contribution to cAMP production. Thus, adenosine contributes to overcome platinum-derived resistance in TNBC, involving the inactivation of the NF-κB pathway and decrease in ERK phosphorylation (partially mediated by A3R).