Histologic, immunohistochemical, and in situ hybridization study of myxoid stroma in feline oral squamous cell carcinoma.

Oral squamous cell carcinoma (oSCC) is a highly invasive malignant neoplasm in cats. Recently, tumor stroma, known as tumor microenvironments, have been considered to play an essential role in tumor progression. However, their role in feline squamous cell carcinoma (SCC) remains unclear. This study aimed to reveal the cancer microenvironment of feline oSCC and evaluate the pathological mechanisms of progression. We used 19 samples from 17 cats with oSCC, which were examined using light microscopy, immunohistochemistry, and in situ hybridization (RNAscope®). Feline oSCCs had two types of stroma, namely fibrotic and myxoid stromal reaction patterns, which were easily distinguished using hematoxylin-eosin staining. The myxoid stroma was rich in hyaluronic acid, which seems to be produced by neoplastic cells. Furthermore, the presence of myxoid stroma was correlated with histological parameters, including the appearance of cancer-associated fibroblasts and tumor budding. Periostin protein expression was also frequently observed in the stroma of feline oSCC and was significantly more common in the myxoid stromal reaction pattern group than in the fibrotic group. Positive signals for periostin mRNA were detected in stromal cancer-associated fibroblasts. This study indicates that the interaction between neoplastic cells and stromal reaction pattern components, such as hyaluronic acid and periostin, may be involved in tumor malignancy. Therefore, we propose that focus be placed not only on the tumor tissue but also on the characterization of the stroma for analyzing feline oSCC.

Monoclonal antibody cetuximab impairs matrix metalloproteinases 2 and 9, epithelial-mesenchymal transition and cell migration in feline oral squamous cell carcinoma in vitro.

Feline oral squamous cell carcinoma (FOSCC) is characterised by invasive and metastatic behaviour and is poorly responsive to current treatments, hence the need for new therapeutic strategies. FOSCC shares molecular targets with human head and neck squamous cell carcinoma (HNSCC), among these the epidermal growth factor receptor. Cetuximab is an anti-epidermal growth factor receptor monoclonal antibody employed in the therapy of HNSCC and, interestingly, previous work in vitro suggested that it displays cytostatic and cytotoxic properties also against FOSCC. With the present study, we aimed at further investigating the effects of cetuximab on invasion and metastasis pathways proven to be relevant in human patients. To this purpose, FOSCC cell lines SCCF1, SCCF2 and SCCF3 were treated with cetuximab for 48/72 h and subjected to Western blot for matrix metalloproteinases-2/9 (MMP-2/9) and epithelial-mesenchymal transition markers vimentin, E-, P- and N-cadherin. Treatment with cetuximab resulted in downregulation of MMP-2/-9 in all of the three cell lines in a dose-dependent manner. Moreover, cetuximab downregulated vimentin and P-cadherin in SCCF1, upregulated E-cadherin whilst downregulating P-/N-cadherins in SCCF2, and impaired P-/N-cadherins in SCCF3. An in vitro scratch test also demonstrated that cetuximab delayed cell migration in SCCF3. These data suggest that cetuximab mitigates invasion and metastasis processes by impairing MMPs and epithelial-mesenchymal transition pathways in FOSCC, indicating that this monoclonal antibody may help to counteract malignant progression and improve the management of locally invasive disease.

Anatomopathological characterization of branchial cysts in slaughtered pigs.

Branchial cysts are a congenital anomaly in humans and other animal species. In this study, twenty commercially bred slaughtered pigs ranging from 120 to 150 days of age, sourced from different farms and lots, were found to have cysts in the oropharyngeal region at meat inspection despite the absence of clinical signs. Two cysts were selected for histopathological examination. The first cyst was surrounded by fibrous connective tissue and lined by a simple single cell layer of epithelium. The second cyst comprised a squamous pseudostratified to simple stratified epithelium, accompanied by a mild inflammatory infiltrate. This cyst was also surrounded by fibrous connective tissue and glands. The pathological diagnosis of branchial cysts in slaughtered pigs was established on the basis of their anatomical location and gross and microscopic findings.

The diagnostic yield of preoperative screening for oral cancer in dogs over 15 years, part 1: locoregional screening.

OBJECTIVE: Determine locoregional diagnostic yield of 4-site screening (head, neck, chest, and abdomen) to diagnose metastatic disease or clinically significant comorbid diseases in dogs with oral cancer. ANIMALS: 381 dogs with histologically confirmed oral tumors. METHODS: Medical records from 381 dogs with histologically confirmed oral tumors that underwent preoperative screening were retrospectively reviewed. RESULTS: Skull and neck CT scan was performed on 348 patients. Bone lysis was present in 74.4% of tumors. Oral squamous cell carcinoma, sarcomas, and T2-T3 (> 2 cm) tumors had a significantly (P < .05) increased incidence of lysis compared to odontogenic and T1 (< 2 cm) tumors, respectively. Minor incidental findings were present in 60.6% of CT scans. Major incidental findings were found in 4.6% of scans. The risk of diagnosing an incidental finding increased by 10% and 20% per year of age for minor and major findings, respectively. Lymph node metastasis was diagnosed with CT or cytology in 7.5% of cases (10.7% of nonodontogenic tumors, 0% of odontogenic tumors). Oral malignant melanoma, oral squamous cell carcinoma, and T3 tumors had the highest prevalence of metastatic disease at the time of staging. The presence of bone lysis was not associated with cervical metastasis. CLINICAL RELEVANCE: Major incidental findings were rare (< 5%) but primarily included secondary extraoral tumors. Lymphatic metastasis was diagnosed in 10.7% of nonodontogenic tumors, but cytology was not performed in the majority of cases and often included only a single mandibular node. Therefore, these results likely underestimate the incidence of lymphatic metastasis. Guided lymph node sampling is highly recommended, especially for oral malignant melanoma, squamous cell carcinoma, and T2-T3 tumors.

Treatment of a nasal angiofibroma in a cat using stereotactic body radiation therapy.

A 14-year-old cat presented with right-sided epistaxis, right facial swelling, hyporexia, and sneezing. A right nasal mass was diagnosed based on dental radiography and computed tomography (CT), and nasal angiofibroma was diagnosed based on histopathology. Treatment consisted of stereotactic body radiation therapy in three consecutive daily doses. Self-limiting grade 3 oral mucositis developed which resolved within 6 weeks. Recheck CT 169 days after treatment confirmed a partial response by RECIST(1) based on digital CT measurements . Disease progression was confirmed on CT 642 days after treatment, per RECIST criteria, with the longest tumor diameter measuring 3.4 cm.

Head and neck squamous cell carcinoma with heterotopic ossification, lymphovascular invasion, and nodal and pulmonary metastases in a 23-year-old Morgan gelding.

Primary squamous cell carcinoma of the head and neck occurs in the skin or squamous epithelial lining tissues of the oral cavity, pharynx, larynx, and sinonasal tract. Although it is a common tumor in horses, distant metastatic spread to the lung is rare. This report describes a case of metastatic pulmonary squamous cell carcinoma in a 23-year-old Morgan gelding. The clinical signs displayed by this gelding in some ways mimicked the typical presentation of equine multinodular pulmonary fibrosis or thoracic lymphoma. The postmortem diagnosis in this case was head and neck squamous cell carcinoma, but a primary site of origin could not be ascertained. Cancer-associated heterotopic ossification (HO) was also identified in this case; this is an exceedingly rare finding with equine pulmonary neoplasia. Key clinical message: Careful physical examination should be undertaken in all horses presenting with clinical signs of intrathoracic disease. Clinical and radiographic abnormalities in this case of pulmonary metastatic disease resembled some of those associated with interstitial pneumonia. Rarely encountered in domestic animal species, there has been only 1 previous report of HO in a case of oronasal carcinoma in a horse.

Carcinome épidermoïde de la tête et du cou avec ossification hétérotopique, envahissement lymphovasculaire et métastases ganglionnaires et pulmonaires chez un hongre Morgan de 23 ans. Le carcinome épidermoïde primitif de la tête et du cou survient dans la peau ou les tissus épithéliaux squameux de la cavité buccale, du pharynx, du larynx et du tractus naso-sinusien. Bien qu'il s'agisse d'une tumeur courante chez les chevaux, la propagation métastatique à distance au poumon est rare. Ce rapport décrit un cas de carcinome épidermoïde pulmonaire métastatique chez un hongre Morgan de 23 ans. Les signes cliniques présentés par ce hongre imitaient à certains égards la présentation typique de la fibrose pulmonaire multinodulaire équine ou du lymphome thoracique. Le diagnostic post-mortem dans ce cas était un carcinome épidermoïde de la tête et du cou, mais un site d'origine primaire n'a pas pu être déterminé. L'ossification hétérotopique associée au cancer (HO) a également été identifiée dans ce cas; il s'agit d'une découverte extrêmement rare avec la néoplasie pulmonaire équine.Message clinique clé :Un examen physique attentif doit être entrepris chez tous les chevaux présentant des signes cliniques de maladie intrathoracique. Les anomalies cliniques et radiographiques dans ce cas de maladie pulmonaire métastatique ressemblaient à certaines de celles associées à la pneumonie interstitielle. Rarement rencontré chez les espèces animales domestiques, il n'y a eu qu'un seul signalement antérieur d'HO dans un cas de carcinome oronasal chez un cheval.(Traduit par Dr Serge Messier).

A subset of equine oral squamous cell carcinomas is associated with Equus caballus papillomavirus 2 infection.

The aetiology of oral squamous cell carcinoma (SCC) in horses is unknown, but papillomavirus infection as well as chronic periodontal disease are suspected to play a pathogenic role. In humans, some oropharyngeal cancers develop in association with human papillomaviruses. Equus caballus papillomavirus 2 (EcPV2) is suspected to play a causal role in the development of equine genital SCC. Given that association, we hypothesized that EcPV2 is associated with the development of oral SCC in horses. We performed standard polymerase chain reaction (PCR) and in-situ hybridization (ISH) for EcPV2 on 31 formalin-fixed paraffin-embedded equine oral SCCs (lingual, gingival, palate) and 10 equine non-SCC oral samples. PCR for EcPV2 was positive in 10/31 (32%) oral SCCs while all non-SCC oral samples were negative. Intense hybridization signals for EcPV2 nucleic acid were detected by ISH within neoplastic epithelial cells in 8/31 (26%) oral SCCs but not in the adjacent normal oral mucosa. No hybridization signals were detected within control samples. This study provides additional support for a pathogenic association of EcPV2 in oral SCC in horses.

A multi-institutional epidemiologic study evaluating environmental risk factors for feline oral squamous cell carcinoma.

Feline oral squamous cell carcinoma (FOSCC) is an aggressive cancer in domestic cats that has no effective treatment option when advanced. Preventative or early diagnostic measures are thus crucial. FOSCC is also a model for human head and neck SCC (HNSCC); strong risk factors in HNSCC include exposure to alcohol, tobacco, areca nut, and high-risk human papillomavirus. Previous studies have identified flea collar and tobacco smoke exposure, feeding canned tuna, canned cat food and cat foods with chemical additives, living in a rural environment, and having outdoor access as risk factors for FOSCC but there was no overlap in the risk factors between studies. In our study, risks for FOSCC were evaluated in an online epidemiologic survey study in 67 cats with FOSCC and 129 control cats. Clumping clay cat litter and flea collar use were significant risk factors for FOSCC on multiple logistic regression with odds ratios of 1.66 (95% CI 1.20-2.30) and 4.48 (95% CI 1.46-13.75) respectively. Crystalline silica is a carcinogen that may be present in all clay cat litters and tetrachlorvinphos is a carcinogen that is present in the most commonly used flea collars in our study. We recommend further investigation into the association between FOSCC and clay-based litter and/or flea collars containing tetrachlorvinphos.

Lymphotropic nanoparticle magnetic resonance imaging for diagnosing metastatic lymph nodes in dogs with malignant head and neck tumours.

Lymphotropic nanoparticle magnetic resonance imaging (LNMRI) utilises ultrasmall paramagnetic iron nanoparticles (USPIOs) for imaging of metastatic lymph nodes in patients afflicted with cancer. LNMRI has been shown to be a highly effective and accurate way to diagnose metastasis in humans but has not been commonly reported on in veterinary medicine. USPIOs are phagocytised by macrophages and then localised to lymph nodes where they create a susceptibility artefact on gradient echo MRI sequences. In this study dogs (n = 24) with naturally occurring head and neck tumours were imaged with LNMRI then had mandibular and retropharyngeal lymph nodes extirpated for histological analysis. Subjective and objective analysis of the LNMRI images was performed and imaging results compared to histology as the gold standard. A total of 149 lymph nodes were included in this study. The overall sensitivity, specificity and accuracy was 64%, 94.4% and 89.3% respectively. However, if dogs with mast cell tumours were excluded from analysis the sensitivity, specificity and accuracy rose to 85.7%, 95.7% and 94.6%. LNMRI is potentially an accurate way to determine the presence of lymph node metastasis in dogs with some types of head and neck tumours. However, LNMRI has only moderate accuracy in dogs with oral or mucocutaneous mast cell tumours in this region.

Use of Cold Atmospheric Plasma in the Treatment of Squamous Cell Carcinoma: in vitro Effects and Clinical Application in Feline Tumors: A Pilot Study.

Cold atmospheric plasma (CAP) has shown promising results against squamous cell carcinoma (SCC) in both in vivo and in vitro assays, mainly in humans and mice. Its applicability for treatment of feline tumors, however, remains unknown. This study aimed to evaluate the anticancer effects of CAP on a head and neck squamous cell carcinoma (HNSCC) cell lineage and against a clinical case of cutaneous SCC in a cat. Control and treatment groups employing the HNSCC cell line (SCC-25) were used, the latter exposed to CAP for 60 seconds, 90 seconds, or 120 seconds. The cells were subjected to the MTT assay nitric oxidation assay and thermographic in vitro analyses. The clinical application was performed in one cat with cutaneous SCC (3 sites). The lesions were treated and evaluated by thermographic, histopathological, and immunohistochemical examinations (caspase-3 and TNF-alpha). Treatment of the SCC-25 cells for 90 seconds and 120 seconds resulted in a significant nitrite concentration increase. Decreased cell viability was observed after 24 hours and 48 hours, regardless of exposure time. However, the cell viability reduction observed at 72 hours was significant only in the 120 seconds treatment. In vitro, the temperature decreased for all treatment times, while the plasma induced a slight increase in mean temperature (0.7°C) in the in vivo assay. Two of the 3 clinical tumors responded to the treatment: one with a complete response and the other, partial, while the third (lower lip SCC) remained stable. Both remaining tumors displayed apoptotic areas and increased expression of caspase-3 and TNF-alpha. Adverse effects were mild and limited to erythema and crusting. The CAP exhibited an in vitro anticancer effect on the HNSCC cell line, demonstrated by a dose-dependent cell viability reduction. In vivo, the therapy appears safe and effective against feline cutaneous SCC. The treatment did not result in a clinical response for 1 of 3 lesions (proliferative lower lip tumor), however, a biological effect was still demonstrated by the higher expression of apoptosis indicators.

Highly recurrent BRAF p.V595E mutation in canine papillary oral squamous cell carcinoma.

Oral squamous cell carcinoma (OSCC) is the most common oral epithelial malignancy in dogs. It exhibits locally aggressive biological behaviour with the potential to metastasize, and a reported 1-year survival rate of 0% when left untreated. Expression studies suggest that aberrant MAPK signalling plays a key role in canine OSCC tumorigenesis, which is consistent with BRAF and HRAS MAPK-activating mutations reported in some tumours. Several morphological subtypes of canine OSCC have been described, with papillary, conventional, and basaloid as the most common patterns. We hypothesized that mutational differences may underlie these phenotypic variations. In this study, targeted Sanger sequencing and restriction fragment length polymorphism assays demonstrate that up to 85.7% of canine papillary OSCC (n = 14) harbour a BRAF p.V595E mutation. Assessment of neoplastic epithelial cell proliferation using Ki67 immunolabelling (n = 10) confirmed a relatively high proliferation activity, consistent with their known aggressive clinical behaviour. These findings underscore a consistent genetic feature of canine papillary OSCC and provide a basis for the development of novel diagnostic and targeted therapeutic approaches that can improve the quality of veterinary care.

Combining radiation therapy with zoledronate for the treatment of osteo-invasive feline oral squamous cell carcinoma.

Feline oral squamous cell carcinoma (FOSCC) is the most common oral tumour diagnosed in pet cats and carries a poor prognosis with <10% one-year survival despite multi-modal therapies. Tumours of the mandible or maxilla are frequently osteo-invasive and pain can result from osteolysis. Zoledronate is a bisphosphonate that inhibits osteoclasts and reduces bone resorption. Radiation therapy (RT) is used to treat FOSCC due to anti-cancer activity and ability to improve quality of life. We hypothesized RT can be safely combined with zoledronate, and that this combinatory therapy would be efficacious, well tolerated, and result in decreased bone resorption in cats with FOSCC. SCCF1 cell line was treated with zoledronate before, concurrently, or after RT, and clonogenic assays were performed to determine if an optimal dosing schedule would be identified. Nine cats with osteoinvasive FOSCC were recruited for treatment with 4 weekly doses of 8 Gy RT combined with zoledronate administered at the first and fourth treatments. Serial CT scans were performed to assess tumour response. Safety and tolerability were monitored with hematologic and biochemical parameters, and acute radiation effects were characterized. Serum c-telopeptide (CTx) and relative bone mineral density (rBMD) by dual -energy X-ray absorptiometry (DEXA) quantified bone resorption. In vitro studies showed no clear benefit to timing of zoledronate with RT, therefore all zoledronate was administered concurrently with RT in FOSCC patients. Based on tumour volume, 4/9 (44.4%) cats achieved partial remission, 4/9 (44.4%) stable disease and 1/9 (11.1%) had progressive disease. The combinatory therapy was well-tolerated based on biochemical measurements, and all patients experienced decreased serum CTx. Combining RT with zoledronate in tumour-bearing cats is safe, well-tolerated, results in a partial remission rate of up to 44%, and decreases serum CTx, a marker of bone resorption.

Environmental risk factors for the development of oral squamous cell carcinoma in cats.

BACKGROUND: Risk factors for oral squamous cell carcinoma (OSCC) in cats are derived from a single study dated almost 20 years ago. The relationship between inflammation of oral tissues and OSCC is still unclear. OBJECTIVES: To investigate previously proposed and novel potential risk factors for OSCC development, including oral inflammatory diseases. ANIMALS: Hundred cats with OSCC, 70 cats with chronic gingivostomatitis (CGS), 63 cats with periodontal disease (PD), and 500 controls. METHODS: Prospective, observational case-control study. Cats with OSCC were compared with an age-matched control sample of client-owned cats and cats with CGS or PD. Owners of cats completed an anonymous questionnaire including demographic, environmental and lifestyle information. RESULTS: On multivariable logistic regression, covariates significantly associated with an increased risk of OSCC were rural environment (OR: 1.77; 95% CI: 1.03-3.04; P = .04), outdoor access (OR: 1.68; 95% CI: 1.07-2.63; P = .02), environmental tobacco smoke (OR: 1.77; 95% CI: 1.05-3; P = .03), and petfood containing chemical additives (OR: 1.98; 95% CI: 1.04-3.76; P = .04). Risk factors shared with CGS and PD were outdoor access and petfood containing chemical additives, respectively. A history of oral inflammation was reported in 35% of cats with OSCC but did not emerge as a risk factor. CONCLUSIONS AND CLINICAL IMPORTANCE: The study proposes novel potential risk factors for OSCC in cats. Although a history of inflammatory oral disease was not significantly more frequent compared with random age-matched controls, OSCC shared several risk factors with CGS and PD.

Investigation of multiple Felis catus papillomavirus types (-1/-2/-3/-4/-5/-6) DNAs in feline oral squamous cell carcinoma: a multicentric study.

Recent evidence suggests a possible association of Felis catus papillomavirus type 2 (FcaPV-2) DNA with feline oral squamous cell carcinoma (FOSCC). In this study, type-specific PCR targeting two genes (L1/E6 or E1/E6) of FcaPV-1/-2/-3/-4/-5/-6 was performed to detect viral DNA in a large amount of FOSCC samples collected in Italy and Austria. FcaPV-1/-2/-3/-4/-5 were detected in 7/113 (6.2%), 7/93 (7.5%), 6/113 (5.3%), 1/113 (0.9%) and 2/113 (1.8%) specimens, respectively, with different prevalences in Italian vs. Austrian samples, whilst FcaPV-6 went undetected. Our results confirms that FcaPV-2 is the most prevalent in FOSCC, followed by FcaPV-1/-3 and suggest that FcaPVs have variable circulation rates in European countries.

Urothelial carcinoma with tonsillar metastasis in a dog.

Given its unusual lymphatic drainage system, the tonsil is a rare site of metastasis, with few reports in the human and veterinary literature. Prognosis in cases of tonsillar metastasis is reportedly poor. We describe here a unique case of urinary bladder urothelial carcinoma (UC) with metastasis to the tonsil in an 11-y-old, spayed female, mixed-breed dog. At presentation, the patient had a history of a growing neck mass and increasing lethargy, hyporexia, weight loss, drooling, and diarrhea for 2 wk. A carcinoma was diagnosed by cytology. Given the poor prognosis, the patient was euthanized. Postmortem examination revealed masses in the inguinal region, cranioventral neck region including tonsil, and urinary bladder. Histologically, the masses were composed of large polyhedral cells arranged in dense sheets and nests with occasional large, clear, intracytoplasmic vacuoles. Neoplastic cells were multifocally positive for uroplakin III and cytokeratin 8/18 by immunohistochemistry. UC with metastasis to tonsil and lymph nodes was diagnosed.

Bilateral second pharyngeal cleft cysts in 2 calves on the same farm.

Pharyngeal cleft cysts (also called branchial cleft cysts) are rare congenital defects of the pharynx region that appear as soft, fluctuant cystic structures on the ventral neck. These cysts are formed by anomalous regression of the pharyngeal clefts during embryonic development and are lined by pseudostratified columnar to squamous, partially ciliated epithelium on histopathology. Development of these cysts is sporadic, with no currently identified risk factors in veterinary species. The cysts are typically unilateral, and primarily diagnosed in mature animals of various species. The objective of this article is to report 2 cases of bilateral second pharyngeal cleft cysts in 2 calves with no shared pedigree, located on the same farm. To the authors' knowledge, this is the first report of geographically linked second pharyngeal cleft cysts in veterinary species, and the first cases of bilateral cysts in cattle. Key clinical message: Pharyngeal cleft cysts are an important differential for soft, fluctuant, and cystic structures on the ventral neck of all species. These cases are typically unilateral, diagnosed in mature animals and are sporadic with no currently identified risk factors in veterinary species.

Kystes bilatéraux de la deuxième fente pharyngée chez deux veaux d'un même élevage. Les kystes de la fente pharyngée (également appelés kystes de la fente branchiale) sont des anomalies congénitales rares de la région du pharynx qui apparaissent sous la forme de structures kystiques molles et fluctuantes sur le cou ventral. Ces kystes sont formés par une régression anormale des fentes pharyngées au cours du développement embryonnaire et sont bordés par un épithélium cylindrique pseudostratifié à squameux, partiellement cilié en histopathologie. Le développement de ces kystes est sporadique et aucun facteur de risque n'est actuellement identifié chez les espèces animales. Les kystes sont généralement unilatéraux et principalement diagnostiqués chez des animaux matures de diverses espèces. L'objectif de cet article est de rapporter deux cas de kystes bilatéraux de la deuxième fente pharyngée chez deux veaux sans pedigree partagé, localisés sur la même ferme. À la connaissance des auteurs, il s'agit du premier rapport de kystes de la deuxième fente pharyngée liés géographiquement chez les espèces vétérinaires, et des premiers cas de kystes bilatéraux chez les bovins.Message clinique clé :Les kystes de la fente pharyngée sont un différentiel important pour les structures molles, fluctuantes et kystiques sur le cou ventral de toutes les espèces. Ces cas sont généralement unilatéraux, diagnostiqués chez des animaux matures et sporadiques sans facteurs de risque actuellement identifiés chez les espèces vétérinaires.(Traduit par Dr Serge Messier).

Current Concepts in Head and Neck Surgery.

This article is intended to "brush up" on the literature updates for the management of head and neck surgeries, particularly mandibulectomy and maxillectomy. Few new techniques have been described in the past decade in dental and oral oncological surgery. A tendency of developing more aggressive surgical strategies to treat complex oral tumors is evident from the recent veterinary literature and the emerging novel techniques for bone regeneration of maxillofacial defects. In addition, this article also focuses on the basic oral surgical oncology principles, an important part of any maxillofacial surgery.

Shear wave elastography of lymph nodes in dogs with head and neck cancer: A pilot study.

Shear wave elastography (SWE) is a novel ultrasound imaging technique, used in human medicine to differentiate metastatic from non-metastatic lymph nodes (LNs) based on higher tissue stiffness. The objective of this pilot study was to evaluate whether canine metastatic LNs were stiffer compared to non-metastatic LNs. SWE of sentinel or regional LNs in dogs with head and neck cancer was performed. Ten elastograms of each LN were acquired. In each elastogram, mean, median, and maximum shear wave velocities (SWVs) were calculated in the most elastic region, the stiffest region, and the entire LN. The means of those SWVs for each region of each LN were subsequently calculated. Furthermore, a stepwise subsampling was performed to assess the effect of the number of acquired elastograms on the consistency of the classification of a LN as metastatic or not. Twenty-four LNs in 15 dogs with head and neck cancer were included, of which 10 LNs were metastatic. Metastatic medial retropharyngeal and mandibular LNs were successfully distinguished from non-metastatic LNs based on higher mean and median SWVs in the stiffest region and higher maximum SWVs in entire LNs. Furthermore, maximum SWVs in the stiffest region of mandibular LNs were higher in metastatic LNs compared to non-metastatic LNs. Downstream analyses demonstrated that at least eight elastograms were necessary to perform reliable analyses. This pilot trial demonstrated that SWE has potential to discriminate metastatic from non-metastatic LNs; however, LN status should be based on at least eight elastograms in future clinical trials.

SLUG is upregulated and induces epithelial mesenchymal transition in canine oral squamous cell carcinoma.

SLUG, encoded by the Snai2 gene, is known to play a role in epithelial-mesenchymal transition (EMT), which contributes to cell invasion and metastasis in some types of human carcinomas. However, the mechanisms and roles of EMT in canine squamous cell carcinoma (SCC) have not yet been elucidated. We have previously established canine oral SCC cell lines, including tonsillar SCC, and in this study, we evaluated the effects of SLUG on the phenotypes regarding EMT of canine SCC cells. First, immunohistochemical analysis revealed that SLUG is upregulated in canine oral SCC tissues compared to that in non-tumoural oral mucosa. Furthermore, gain-of-function and loss-of-function of SLUG revealed that SLUG partly contributed to migration and invasion of cells, as well as the upregulation of EMT markers such as vimentin and SNAIL. Thus, the current study suggests that SLUG promotes cell migration and invasion through EMT induction in canine oral SCC, as well as human cancers.

Evaluation of setup errors of immobilization device for radiation therapy in companion animals.

Background: Intensity-modulated radiotherapy (IMRT), which allows generating steep dose gradients, is a beneficial treatment for companion animals with adjacent target and risk organs. IMRT is essential for high setup accuracy for avoiding overdose to risk organs, and optimal radiotherapy is important for evaluating the setup accuracy of companion animals. Aim: To use an immobilization device to evaluate setup errors in radiotherapy for companion animals. Methods: We calculated setup errors in radiotherapy for 386 animals (dogs and cats; 3,261 registration images) that underwent radiotherapy between 2016 and 2022. The companion animals were immobilized with a customized bite block and vacuum lock device. A quantile-quantile plot with 95% confidence interval (CI) was used to evaluate the histogram of the setup errors, and the systematic and random setup errors were calculated for each region (brain, head and neck, chest and abdomen, pelvis, and spine). Results: The setup error in each direction presented an extremely narrow-interval histogram, with the following lower and upper 95% CIs: cranial-caudal (-0.08, -0.06 cm); left-right (-0.04, -0.02 cm); and dorsal-ventral (-0.13, -0.11 cm). The mean systematic setup error was 0.16 cm (range: 0.12-0.36 cm), and the random error was 0.15 cm (range: 0.08-0.34 cm). The pelvis showed the highest systematic and random setup errors (mean: 0.36 and 0.23 cm, respectively). Conclusion: The use of an immobilization device enables highly accurate radiotherapy for companion animals (95% CI < 0.15 cm).