Search

Trace elements (including heavy metals) can negatively affect the environment and the health of living beings. Biomonitoring is a transdisciplinary tool to evaluate this pollution type and its respective consequences in ecosystems, food chains, and webs. This review used systematic methods to identify published literature on biomonitoring of heavy metal(loid)s using wild mammals on the Iberian Peninsula. A total of 30 different mammalian species (30/141) were included in 62 Iberian biomonitoring studies: 22 species from terrestrial habitats and 8 from aquatic habitats. Carnivores (including piscivores) were the most represented in both habitat types (7/22 in terrestrial; 8/8 in aquatic). Most studies used more than one tissue (2.8 ± 1.3), with a preference for the liver and kidney. Cd was the most determined metal, measured in 45% of the biomonitoring studies analysed, highlighting its potential health impact on mammals. Further research is crucial to provide more information on mammalian species' susceptibility to this One Health problem, and to cover more habitats, trophic chains, and (or) geographical areas.

Wildlife forensics is a science field with a remarkable potential to provide accurate information regarding nature conservation and One Health. Wildlife crimes are now a persistent target of public opinion and the concern of conservation professionals, which is constantly putting pressure on governmental and non-governmental entities. Moreover, the cross-species transmission of pathogens is becoming more and more frequent, endangering the interconnected health of humans, animals and the environment (One Health). This review intends to briefly present and illustrate the potential of wildlife forensic sciences not only in crime solving, but also regarding health sciences and species conservation. By allowing target species identification, recreating the crime scene, and considering their contribution to diseases and ecosystems’ surveillance, wildlife forensics are now constantly developing and improving. A cooperative and multidisciplinary approach (with the inclusion of forensic sciences) is necessary to avoid wildlife crimes, disease outbreaks, environmental disasters and to promote a sustainable and healthy future for all the living beings.

This work aimed to understand how lifelong exercise training promotes the remodelling of the immune system and prostate signalome in a rat model of PCa. Fifty-five male Wistar rats were divided into four groups: control sedentary, control exercised, induced PCa sedentary and induced PCa exercised. Exercised animals were trained in a treadmill for 53 weeks. Pca induction consisted on the sequential administration of flutamide, N-methyl-N-nitrosourea and testosterone propionate implants. Serum concentrations of C-reactive protein (CRP) and tumor necrosis factor (TNF)-like weak inducer of apoptosis (TWEAK) were not different among groups. Peripheral levels of γδ T cells were higher in Pca exercised group than in the PCa sedentary group (p

Wild boars are wild ungulates with a wide distribution in Europe, with a relevant role in wildlife and public health. In Spain, high (and sometimes artificial) densities of wild boars are responsible for several health problems. Regular surveys, with hunters' collaboration, are crucial to monitor these diseases. Histological analyses were performed for lung, liver, and kidneys from 72 wild boars (58 from Zamora, 16 from Palencia). Lungs were the most affected organs, mainly revealing parasitic pneumonia (34.7%). Hydropic, vacuolar, and other cellular changes (33.3%) and congestion (16.7%) were found in the liver, and only 30.6% of the wild boars presented no alterations in this organ. Regarding the kidney, non-purulent nephritis (22.2%) was the most common lesion. This study gives an overview of the health status of wild boar populations in Castile and León. Other laboratory analyses are needed to obtain definitive diagnoses of these lesions, reach other conclusions, or apply any mitigation strategies to protect animals' or consumers' health.

The growing incidence of prostate cancer has prompted a great investment in basic biology and translational studies to develop new therapies. Multiple animal models have been established to study etiological factors, cancer-preventive strategies and the molecular determinants of aggressiveness and metastases. The rat model of prostate cancer induced by chemical carcinogen N-methyl-N-nitrosourea (MNU) and testosterone exposure has become an important tool to study prostatic carcinogenesis and chemopreventive approaches. Over prolonged treatment, this model develops prostatic lesions that closely mimic those observed in human patients. By modifying the experimental conditions, different research groups have been able to induce a vast spectrum of lesions, ranging from early prostatic intraepithelial neoplasia to metastatic cancer. These carefully tuned experimental settings allowed researchers to test lifestyle interventions, and different pharmacological and chemopreventive strategies. However, this model's great flexibility requires careful planning to ensure that the experimental conditions are adequate to obtain the spectrum of lesions intended. The present review addresses such issues, highlighting the value of the rat prostate cancer model and the multiple challenges and opportunities it offers to researchers worldwide.

This study evaluated the expression of vimentin and Ki-67 proliferative index (PI) by immunohistochemistry in 30 canine gastric carcinomas (GCs) and a possible association with clinical and pathological features and patient’s survival time. Vimentin immunoreactivity was assessed in neoplastic cells (in primary lesions, emboli, and metastases) and tumor-associated stroma (TAS) of canine GCs. Ki-67 PI was quantified in the neoplastic epithelial component. Vimentin immunolabeling in neoplastic cells was found in 30% of the primary lesions, in 82% of the neoplastic emboli, and in 50% of the metastases; in TAS, it was observed in all cases. A mean of 16% of the TAS was immunolabeled for vimentin. High vimentin immunolabeling in the TAS (>16%) was detected in 40% of cases. The average value of Ki-67 PI was 50%, and 80% of the lesions had Ki-67 PI above 20%. Vimentin immunolabeling in neoplastic cells was more frequent in less-differentiated carcinomas (diffuse [29%] and indeterminate types [75%]) than well-differentiated carcinomas (intestinal type [0%], P = .049). No significant differences were observed in vimentin immunolabeling in the TAS or Ki-67 PI according to histological diagnosis, depth of invasion, presence of neoplastic emboli or metastases. However, vimentin immunolabeling in the TAS was positively correlated with Ki-67 PI ( r = .394, P = .031). Furthermore, a moderate negative correlation was observed between Ki-67 PI and survival time ( r = −0.540). Our results suggest that vimentin and Ki-67 PI have potential for providing prognostic information in cases of canine GCs.

Among the transmissible spongiform encephalopathies (TSEs), chronic wasting disease (CWD) in cervids is now a rising concern in wildlife within Europe, after the detection of the first case in Norway in 2016, in a wild reindeer and until June 2022 a total of 34 cases were described in Norway, Sweden and Finland. The definite diagnosis is postmortem, performed in target areas of the brain and lymph nodes. Samples are first screened using a rapid test and, if positive, confirmed by immunohistochemistry and Western immunoblotting. The study of the genetics of the prion protein gene, PRNP, has been proved to be a valuable tool for determining the relative susceptibility to TSEs. In the present study, the exon 3 of PRNP gene of 143 samples from red deer (Cervus elaphus) and fallow deer (Dama dama) of Portugal was analyzed. Three single nucleotide polymorphisms (SNPs) were found in red deer – codon A136A, codon T98A, codon Q226E – and no sequence variation was detected in fallow deer. The low genetic diversity found in our samples is compatible with previous studies in Europe. The comparison with results from North America, suggests that the free-ranging deer from our study may present susceptibility to CWD, although lack of experimental data and the necessity of extensive survey are necessary to evaluate these populations.

Prostate cancer (PCa) is a complex, heterogenous and multifocal disease, which is debilitating for patients and often fatal - due to bone metastasis and castration-resistant cancer. The use of murine models that mimic human disease has been crucial in the development of innovative therapies and for better understanding the mechanisms associated with initiation and progression of PCa.This review presents a critical analysis of murine models for the study of PCa, highlighting their strengths, weaknesses and applications.In animal models, disease may not occur exactly as it does in humans, and sometimes the levels of efficacy that certain treatments obtain in animal models cannot be translated into clinical practice. To choose the most appropriate animal model for each research work, it is crucial to understand the anatomical and physiological differences between the mouse and the human prostate, while it is also important to identify biological similarities and differences between murine and human prostate tumors. Although significant progress has already been made, thanks to many years of research and study, the number of new challenges and obstacles to overcome mean there is a long and difficult road still to travel.

Erinaceus europaeus is a cosmopolitan mammalian species broadly distributed in Europe, from natural to suburban areas. Due to its ecological role and susceptibility to distinct zoonotic agents, E. europaeus could be a suitable sentinel candidate for many global problems that negatively affect human and animal health. Hedgehogs can work as bioindicators to environmental contamination and can be hosts for multiple tickborne zoonotic agents. Thus, people who directly or indirectly make physical contact with this species are exposed to a variety of threats. Moreover, it has also been studied as an indicator for antibiotic resistance, which was already confirmed for tetracyclines. Additionally, it was also reported as a reservoir for methicillin-resistant Staphylococcus aureus (MRSA). More recently, hedgehogs have been recently recognised as potential reservoirs of MERS-CoV-like strains. Among other animals, this species can possibly represent an intermediate reservoir for SARS-CoV-2. The aim of this review is to briefly expose the scientific attainments about hedgehog health, namely agents, diseases, and threats that significantly affect general health concerns and that contribute to achieve One Health principles.

Heavy metal and metalloid pollution is a matter of concern in animal, human and environmental health (One Health) and also in wildlife conservation worldwide. Studying wild mammals in toxicology has been contributing significantly to our knowledge, namely to find out the most critical regions, to understand bioaccumulation and biomagnification phenomena or to evaluate their toxic effects. However, not all the animal tissues and organs provide the same information or should be interpreted in the same way. The best sample to use will depend on the objectives and conditions of the study. This review aims to compare invasive and non-invasive samples to biomonitor heavy metals, providing a brief resume of their advantages, limitations and examples of use. Further research, using a wider range of mammalian species, is required to establish what information can be obtained in biomonitoring studies that use non-invasive samples (such as hair, faeces and parasites) and/or invasive samples (such as blood, liver, kidney, bone and other organs).

Prostate cancer (PCa) is one of the most common cancers in men, with a huge impact on their health. The use of Castanea sativa Mill. flowers (CFs) in beverages has been reported, through ancestral claims, as having health benefits. In vitro research has evidenced the properties of CFs, such as antitumor and antioxidant activities. This study aimed to evaluate the effects of CF extract in an animal model of PCa. Forty male Wistar Unilever rats were randomly assigned to four groups: control, induced, control + CF, and induced + CF groups. Animals from the induced groups were exposed to a multistep protocol for PCa induction. The CF extract, rich in trigalloyl-HHDP-glucoside and obtained via decoction, was administered to the CF groups in drinking water (3 mg per animal per day) for 49 weeks. Animals were sacrificed at 61 weeks of age. Regarding the effects of CFs on dorsolateral prostate tumorigenesis, no significant differences were observed between the induced and induced + CF groups. However, animals exposed to the CF extract showed fewer inflammation areas on the dorsolateral prostate lobe than those not exposed to CF. Moreover, the CF extract alleviated the hepatic oxidative stress associated with the multistep protocol, resulting in lower levels of lipid peroxidation. These results suggest that CF extract has antioxidant and anti-inflammatory properties. This journal is. This work was supported by European Investment Funds by FEDER/COMPETE/POCI - Operational Competitiveness and Internationalization and National Funds by FCT - Portuguese Foundation for Science and Technology, under the projects UIDB/04033/2020 (CITAB), UIDB/00690/2020 (CIMO), UIDB/50006/2020 (LAQV), UIDB/CVT/00772/2020 (CECAV), and UIDP/00616/2020 (CQ-VR), the project RUNawayPCa (POCI-01-0145- FEDER-016728 and PTDC/DTP-DES/6077/2014), and PhD fellowship SFRH/BD/136747/2018. L. Barros also acknowledges national funding by FCT, P.I., through the institutional scientific employment program-contract for her contract. The Interreg Program received financial support from the Project IBERPHENOL, Project Number 0377_IBERPHENOL_6_E, cofinanced by the European Regional Development Fund (ERDF) through POCTEP 2014-2020. info:eu-repo/semantics/publishedVersion

Transmissible Spongiform Encephalopathies (TSEs) or prion diseases are a fatal group of infectious, inherited and spontaneous neurodegenerative diseases affecting human and animals. They are caused by the conversion of cellular prion protein (PrPC) into a misfolded pathological isoform (PrPSc or prion- proteinaceous infectious particle) that self-propagates by conformational conversion of PrPC. Yet by an unknown mechanism, PrPC can fold into different PrPSc conformers that may result in different prion strains that display specific disease phenotype (incubation time, clinical signs and lesion profile). Although the pathways for neurodegeneration as well as the involvement of brain inflammation in these diseases are not well understood, the spongiform changes, neuronal loss, gliosis and accumulation of PrPSc are the characteristic neuropathological lesions. Scrapie affecting small ruminants was the first identified TSE and has been considered the archetype of prion diseases, though atypical and new animal prion diseases continue to emerge highlighting the importance to investigate the lesion profile in naturally affected animals. In this report, we review the neuropathology and the neuroinflammation of animal prion diseases in natural hosts from scrapie, going through the zoonotic bovine spongiform encephalopathy (BSE), the chronic wasting disease (CWD) to the newly identified camel prion disease (CPD).

TFF1 expression is markedly reduced in human GCs, suggesting that TFF1 is a tumor suppressor for human gastric cancer. The present study evaluated the expression and distribution pattern of TFF1 in paraffin-embedded canine gastric tissue samples, including normal mucosa (n = 3), polyps (n = 8), carcinomas (n = 31) and their adjacent non-neoplastic mucosa (n = 30), neoplastic emboli (n = 14), and metastatic lesions (n = 9), by immunohistochemistry (IHC). All normal gastric tissues expressed TFF1 in the superficial foveolar epithelium and mucopeptic cells of the neck region. Most gastric polyps (GPs) displayed immunoreactivity for TFF1 in &gt, 75% of the epithelial component. In GCs, the expression of TFF1 was found reduced in 74.2% of the cases. The level of TFF1 expression had a decreased tendency from normal gastric mucosa to GPs and GCs (p &lt, 0.05). No significant differences in the expression of TFF1 were found in GCs, according to age, sex, histological type based on World Health Organization (WHO) and Lauren classification, tumor location, depth of tumor invasion, presence of neoplastic emboli or metastatic lesions. The median survival time of GC patients with preserved and reduced TFF1 immunoexpression were 30 and 12 days, respectively. Kaplan–Meier analysis revealed no significant survival differences between the two groups (p &gt, 0.05). These findings suggest that TFF1 protein may play a role in canine gastric carcinogenesis, and further studies are necessary to define its usefulness as a prognostic indicator in canine gastric carcinoma.

Purpose: Prostate cancer is a major cause of cancer-related death in males worldwide and, in addition to impairing prostate function, also causes testicular adaptations. In this study, we aim to investigate the preventive effect of exercise training on PCa-induced testicular dysfunction. Methods: As a model, we used fifty Wistar Unilever male rats, randomly divided in four experimental groups. Prostate cancer was chemically and hormonally induced in two groups of animals (PCa groups). One control group and one PCa group was submitted to moderate intensity treadmill exercise training. Fifty weeks after the start of the training the animals were sacrificed and sperm, prostate, testis and serum were collected and analyzed. Sperm concentration and morphology, and testosterone serum levels were determined. In addition, histological analyses of the testes were performed, and testis proteomes and metabolomes were characterized. Results: We found that prostate cancer negatively affected testicular function, manifested as an arrest of spermatogenesis. Oxidative stress-induced DNA damage, arising from reduced testis blood flow, may also contribute to apoptosis of germ cells and consequential spermatogenic impairment. Decreased utilization of the glycolytic pathway, increased metabolism of ketone bodies and the accumulation of branched chain amino acids were also evident in the PCa animals. Conversely, we found that the treadmill training regimen activated DNA repair mechanisms and counteracted several metabolic alterations caused by PCa without impact on oxidative stress. Conclusions: These findings confirm a negative impact of prostate cancer on testis function and suggest a beneficial role for exercise training in the prevention of prostate cancer-induced testis dysfunction. published

Aim: This work intended to improve the knowledge of the rat model of prostate cancer (PCa) by ultrasonographic monitoring. Materials and Methods: Male Wistar rats were divided into control (n=8) and PCa (n=14) groups. PCa development was induced in the PCa group through the sequential administration of the anti-androgenic drug flutamide, testosterone propionate and the carcinogenic N-methyl-N-nitrosourea. The prostate was evaluated by ultrasonography at five timepoints along 49 weeks of the experimental protocol. Ventral prostate lobes were observed in all ultrasonographic examinations. Results: The ventral prostate area of the control group increased gradually between the first and the last ultrasonographic examination. The ventral prostate area of PCa groups decreased due to flutamide administration and increased after androgen and carcinogen administration. The area of the dorsal prostate lobe increased between the fourth and the fifth ultrasonographic examination. In the last ultrasonographic examination, hypoechoic and anechoic lesions were observed in the PCa group. Conclusion: To our knowledge, this is the first study presenting a follow-up of rat prostatic dimensions by ultrasonography. Ultrasonography is a feasible approach for prostate cancer monitoring in experimental models. published

Recent studies have described Spirocerca lupi-like nematodes in the stomach of red foxes (Vulpes vulpes) in Europe. A phylogenetic analysis of those specimens using mitochondrial DNA and their morphological reexamination allowed their characterization as a different species, Spirocerca vulpis. Between the years of 2010 and 2017, roundworms were collected from seven red foxes of northeastern Portugal found at necropsy with nodular lesions on their stomach wall. Histopathological analysis of four foxes revealed granulomatous lesions of the gastric nodules. On morphological assessment, by light microscopy, nematodes revealed the presence of six triangular teeth-like buccal capsule structures, which are absent in S. lupi. Polymerase chain reaction was run to amplify a 551 bp partial fragment of the cytochrome c oxidase subunit 1 gene. Sequences were 99% similar to S. vulpis (85% coverage) of red foxes from Spain and Bosnia and Herzegovina, 99% similar (99% coverage) to sequences of Spirocerca sp. of red foxes from Denmark and 93% similar (99% coverage) to S. lupi from South Africa. This is the first report of S. vulpis in foxes or any other host from Portugal.

The production of chestnut (Castanea sativa Miller) is mostly concentrated in Europe. Chestnut is recognized by its high content of antioxidants and phytosterols. This work aimed to evaluate the effects of dietary chestnut consumption over physiological variables of FVB/n mice. Eighteen FVB/n male 7-month-old mice were randomly divided into three experimental groups (n = 6): 1 (control group) fed a standard diet, 2 fed a diet supplemented with 0.55% (w/w) chestnut, and 3 supplemented with 1.1% (w/w) chestnut. Body weight, water, and food intake were recorded weekly. Following 35 days of supplementation, the mice were sacrificed for the collection of biological samples. Chestnut supplementation at 1.1% reduced abdominal adipose tissue. Lower serum cholesterol was also observed in animals supplemented with chestnut. There were no significant differences concerning the incidence of histological lesions nor in biochemical markers of hepatic damage and oxidative stress. These results suggest that chestnut supplementation may contribute to regulate adipose tissue deposition.

Head and neck squamous cell carcinomas (HNSCCs) associated with human papillomavirus (HPV) occur specifically in the tonsils and the tongue base, but the reasons for this specificity remain unknown. We studied the distribution of oral and pharyngeal lesions in HPV16-transgenic mice where the expression of all the HPV16 early genes is targeted to keratinising squamous epithelia by the cytokeratin 14 (Krt14) gene promoter. At 30 weeks of age, 100% of mice developed low- and high-grade intraepithelial dysplasia at multiple sites. Twenty per cent of animals developed invasive cancers that remarkably were restricted to the tongue base, in association with the circumvallate papilla. The lesions maintained expression of CK14 (KRT14) and the HPV16 E6 and E7 oncogenes, and displayed deregulated cell proliferation and up-regulation of p16INK4A . Malignant lesions were poorly differentiated and destroyed the tongue musculature. We hypothesised that the tongue base area might contain a transformation zone similar to those observed in the cervix and anus, explaining why HPV-positive cancers target that area specifically. Immunohistochemistry for two transformation zone markers, CK7 (KRT7) and p63 (TP63), revealed a squamocolumnar junction in the terminal duct of von Ebner's gland, composed of CK7+ luminal cells and p63+ basal cells. Dysplastic and invasive lesions retained diffuse p63 expression but only scattered positivity for CK7. Site-specific HPV-induced carcinogenesis in the tongue base may be explained by the presence of a transformation zone in the circumvallate papilla. This mouse model reproduces key morphological and molecular features of HPV-positive HNSCC, providing a unique in vivo tool for basic and translational research. © 2020 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Ocular thelaziosis is caused by nematodes of the genus Thelazia (Spirurida, Thelaziidae), which inhabit the surface of the eyes and associated tissues. Thelazia callipaeda affects a range of mammal species, including humans, and in the last two decades has been reported in multiple European countries, being classified as an emergent vector-borne pathogen. In Portugal T. callipaeda is endemic in north-eastern areas, where it has been reported in domestic dogs, cats, red foxes (Vulpes vulpes) and wild European rabbits (Oryctolagus cuniculus). We report, for the first time, T. callipaeda in a beech marten (Martes foina) from Portugal and highlight the presence of haplotype 1 as the only one found in Europe, irrespective of the host species and geographical area of provenience.

Dysregulation of cellular iron homeostasis in human breast cancer is reflected by the altered expression of regulatory proteins. The expressions of iron-related proteins in the mammary glands of cats and dogs have not been assessed. We evaluated the expressions of ferritin, ferroportin, hepcidin and transferrin receptor 1 in benign and malignant mammary gland lesions in cats and dogs. Iron deposition was detected using Perls' Prussian blue staining. We found no major differences in the expression of iron-related proteins between benign and malignant mammary gland lesions in either cats or dogs; however, these species exhibited accumulation of iron in benign lesions. Our findings provide an explanation for the absence of higher iron requirements by tumor cells in these animals. Further investigation of local iron homeostasis in cats and dogs and differences in their physiology compared to human breast cancer is required.

Simple Summary Observation of small ruminants showing differing degrees of leanness or emaciation is a common occurrence at slaughterhouses. Although either condition may result from similar causes, emaciation and cachexia are usually pathological conditions, warranting total condemnation of the carcass during post-mortem inspection. This is done in order to prevent unfit meat from entering the human food chain. Scrapie, a naturally occurring transmissible spongiform encephalopathy in small ruminants, is characterized by loss of body conditioning and a wasting appearance. Since atypical scrapie has been identified as occurring at a low, but very consistent, the prevalence in small ruminant populations, it is advisable to include this disease as a differential diagnosis of wasting conditions detected during meat inspection at the abattoir. Vigilance for detection of putative scrapie in slaughterhouses, and its differential diagnosis from other conditions associated with wasting carcasses, are of paramount importance for post-mortem decisions on the fate of carcasses, offal, as well as animal by-products. Abstract Wasting disease in small ruminants is frequently detected at slaughterhouses. The wasting disorder is manifested by the deterioration of the nutritional and physiological state of the animal indicated by thinness, emaciation, and cachexia. Evidence of emaciation and cachexia, alone, are pathological conditions leading to carcass condemnation during an inspection. Several diseases are associated with a wasting condition, including scrapie, pseudotuberculosis, tuberculosis, paratuberculosis, Maedi Visna, and tumor diseases. On the other hand, parasitic diseases, nutrition disorders, exposure or ingestion of toxins, metabolic conditions, inadequate nutrition due to poor teeth, or poor alimentary diet are conditions contributing to poor body condition. Classical and atypical scrapie is naturally occurring transmissible spongiform encephalopathies in small ruminants. The etiological agent for each one is prions. However, each of these scrapie types is epidemiologically, pathologically, and biochemically different. Though atypical scrapie occurs at low incidence, it is consistently prevalent in the small ruminant population. Hence, it is advisable to include differential diagnosis of this disease, from other possibilities, as a cause of wasting conditions detected during meat inspection at the abattoir. This manuscript is a review of the measures in force at the abattoir for scrapie control, focusing on the differential diagnosis of gross lesions related to wasting conditions detected in small ruminants during meat inspection.

Malignant transformation is often associated with abnormal protein glycosylation expressed, amongst others, by the accumulation of simple mucin-type carbohydrates namely Tn and Sialyl-Tn (STn) antigens. These are usually limited in normal tissues and their increased expression has been associated with cancer progression and poor prognosis. This study aims to evaluate the role of Tn and STn antigens in the neoplastic transformation of the canine gastric mucosa and to correlate their putative immunoexpression alterations with some pathological features. Tn and STn antigens expression were immunohistochemically evaluated in canine normal gastric mucosa (n = 3), gastric polyps (n = 9) and gastric carcinomas (n = 25), neoplastic emboli (n = 12) and metastases (n = 8). In normal gastric mucosa, Tn antigen was detected in the gastric epithelial cells, while STn antigen was absent. Similarly, all gastric polyps expressed Tn antigen, but none displayed STn antigen immunostaining. In carcinomas, Tn antigen was expressed in 96% of the cases and STn antigen in 68% of the neoplasms. STn antigen was significantly higher in carcinomas compared with normal mucosa (P < .05). No correlation was found between each antigen and the different subtypes of tumours according to WHO classification, tumour differentiation, lymph vascular invasion or metastasis. All neoplastic emboli expressed both antigens, and the expression score was similar or higher than that displayed by the neoplastic cells of the primary tumour. The high prevalence of STn antigen in gastric carcinomas compared with normal mucosa highlights the cancer-associated nature of this antigen. Our results link STn antigen expression to neoplastic transformation and suggest that it may be a useful marker of gastric cancer progression in dogs.