Prognostic factors and survival following radiation therapy for canine nasal tumors: A single-institution retrospective study of 166 cases.

Background: Prognostic factors in dogs with nasal tumors include several variables. However, factors that can measure prognosis have not yet been identified due to considerable divergence among reports. Aim: To describe the computed tomography (CT) imaging, treatment, and outcomes of dogs with nasal tumors, as well as detect negative prognostic factors through the analysis of a substantial number of cases from a single institution. Furthermore, based on CT findings, this study aimed to identify independent prognostic factors for nasal tumors in dogs. Methods: A total of 166 client-owned dogs were diagnosed with nasal tumors at Gifu University Veterinary Hospital between 2015 and 2019. Data were retrospectively collected from the electronic medical records. Results: Univariate analysis revealed a significant difference in survival time between adenocarcinoma and squamous cell carcinoma in 166 canine nasal tumors treated with megavoltage (MeV) radiation therapy at a single institution (p = .015). There was a significant difference in survival time between carcinoma and sarcoma (p = .04). Regarding CT imaging findings, significant differences in survival time were observed for frontal sinus invasion (p = .007), cribriform plate destruction (p < .001), and lymph node metastasis (p = .003). Multivariate Cox regression analysis was performed to assess frontal sinus invasion, cribriform plate destruction, histopathologic subtypes, and lymph node metastasis as negative prognostic factors; however, only cribriform plate destruction was a significant negative prognostic factor for survival time (p = .004). Conclusion: Multivariate Cox regression analysis showed that cribriform plate destruction was the main factor in predicting a negative prognosis among 166 canine nasal tumors treated with MeV radiation therapy at a single institution. Therefore, we propose a new 2-tier staging classification for canine nasal tumors with the presence or absence of cribriform plate destruction based on CT examination as the only evaluation factor.

Lingual neoplasia in nonhuman primates: Description of five cases and a literature review.

BACKGROUND: Documentation of lingual tumors is scarce in nonhuman primates. METHODS: Through a multi-institutional retrospective study we compile cases of primary and metastatic neoplasia in non-human primates. RESULTS: We describe five cases of lingual neoplasia. Three cases are primary lingual tumors: chondro-osteoblastic lipoma in a howler monkey, squamous cell carcinoma, and fibroma in two baboons. We describe two cases of metastatic lymphoma in the tongue in rhesus macaques. A literature review of published lingual neoplasia in nonhuman primates is included in this manuscript. CONCLUSION: Lingual neoplasia is seldom reported in non-human primates.

Comparison of Three Chemotherapy Protocols With Electrochemotherapy for the Treatment of Feline Cutaneous Squamous Cell Carcinoma.

Electrochemotherapy (ECT) with intravenous (IV) and/or intratumoral (IT) bleomycin has shown considerable efficacy in the treatment of non-resectable feline cutaneous squamous cell carcinoma (cSCC), boasting response rates of up to 95%, but other chemotherapy protocols have not yet been investigated. The objective of this prospective multicentre study was to compare the overall response rate (ORR) and progression-free interval (PFI) between cats with cSCC treated with ECT using IT and IV carboplatin (IV + IT), IV carboplatin (IV) or IV bleomycin (IV). A total of 44 cats with unresectable cSCC across three centres were enrolled and treated with ECT using carboplatin IV + IT (n = 10), carboplatin IV (n = 11) or bleomycin IV (n = 23). Treatment response according to RECIST criteria was recorded at 2 and 4 weeks post-treatment, and patients were followed until disease progression and/or death. All three groups were comparable regarding age, sex, weight, and lesion size. Adverse events were generally mild, localised and similar between groups. ORRs were 90.0% (carboplatin IV + IT), 90.9% (carboplatin IV) and 95.6% (bleomycin IV) and were not significantly different (p = 0.79). Median PFI was not reached for carboplatin IV + IT or carboplatin IV and was 566 days for bleomycin IV, with no significant difference between the three groups (p = 0.81). This study suggests that ECT using IV or IV + IT carboplatin is a reasonable alternative therapeutic option for managing cSCC, and further studies are warranted to compare outcomes between treatment protocols.

Immunostaining and gene expression of epidermal growth factor receptors (HER1/HER2) in canine cutaneous squamous cell carcinoma.

Cutaneous squamous cell carcinoma (cSCC) is a neoplasm type often diagnosed in dogs. However, studies focused on further investigating its molecular biology, mainly biomarkers to help implementing new therapies, remain scare in the literature. Thus, immunostaining and the gene expression of epidermal growth factor receptors (HER1 and HER2) in canine cSCC presenting different cell differentiation degrees were herein assessed. Thirty-two (32) canine cSCC were selected, classified based on to their cell differentiation degree and subjected to immunohistochemical study to assess HER1 and HER2 immunostaining intensity and distribution. In addition, HER1 and HER2 gene expression was investigated through real-time PCR. Membranous and cytoplasmic immunostaining were observed in both markers. HER2 prevailed in poorly differentiated cSCC; there was positive protein expression correlation between both markers. Mean HER1 gene expression was higher in moderately differentiated, whereas mean HER2 gene expression was higher in poorly differentiated cSCC. Moreover, there was gene expression correlation between markers, regardless of cell differentiation degree. Thus, HER2 protein immunostaining and gene expression were higher in poorly differentiated canine cSCC and it enabled understanding that increase observed in this epidermal growth factor receptor is proportional to this neoplasm's cell differentiation degree in canine species. Results in the current study helped better understanding canine cSCC's molecular biology; however, it is relevant studying other markers aiming to investigate signaling pathways.

Surgical management of squamous cell carcinoma of the canine male external genitalia: 15 cases (1994-2020).

Fifteen male dogs with squamous cell carcinoma of the external genitalia were admitted for further investigation and surgical management between 1994 and 2020. The dogs belonged to various breeds. Thirteen dogs were intact and two were castrated with a median age of 8 years and a median weight of 28 kg. Seven dogs were white-coated and eight nonwhite coated. Scrotal ablation and orchiectomy were performed in four dogs, partial penile amputation in two, partial penile amputation plus partial preputial ablation in one, penile amputation, and scrotal urethrostomy in seven, and local preputial excision in one dog. Postoperative complications included hemorrhage in 10 dogs, bruising at the urethrostomy site in seven, and urethrostomy dehiscence in one dog. Tumor recurrence was recorded in six dogs. Dogs with poorly differentiated tumors that had tumor recurrence had shorter survival and worse prognosis compared to those with well and moderately differentiated tumors. The mean survival time was 48.132 months. After a median follow-up of 23 months (range: 8 to 72 months), eight dogs were alive, five were euthanized and two dogs died from unrelated causes. Surgical excision seems to be a treatment option for dogs with squamous cell carcinoma of the external genitalia.

Description of outcome and adverse events in 21 cats with locally advanced nasal planum squamous cell carcinoma treated with electrochemotherapy.

OBJECTIVES: Squamous cell carcinoma (SCC) is the most common tumour in the nasal planum of cats. Surgery has traditionally been the treatment of choice but might not be feasible in locally advanced scenarios. Electrochemotherapy (ECT) has shown good control in superficial tumours, but there is a lack of robust information about efficacy in locally advanced cases. The aim of this study was to assess the safety and efficacy of ECT in the treatment of locally advanced stage nasal planum SCC in cats. METHODS: The clinical database of a veterinary referral hospital was searched retrospectively for cats diagnosed with a locally advanced nasal planum SCC (T3N0M0 or T4N0M0) that had received ECT. Local response, adverse events and outcome were documented. The data were evaluated by inferential statistics and correlations between response, recurrence, feline immunodeficiency virus/feline leukaemia virus status, number of treatments, voltage and severity of adverse events, with Kaplan-Meier curves and log-rank tests. Statistical significance was set at P <0.05. RESULTS: In total, 21 cats were enrolled over a 4-year period. Nineteen cats achieved a complete response (CR) and two cats a partial response (PR) for an overall response rate of 100%. Cats achieving a CR had a median disease-free interval of 182 days (range 128-327) and those with a PR had a median progression-free survival of 156.5 days (range 122-191). The median time to progression was not reached. The overall survival was 453 days for a median follow-up of 341 days (range 191-989). Of the cats, 62% had grade 3 or 4 toxicities, but no deaths due to the treatment were documented. Only voltage was correlated with longer survival (P = 0.001). CONCLUSIONS AND RELEVANCE: ECT appears to be an effective treatment for feline nasal planum SCC and could be considered a first-line therapy for locally advanced cases. Toxicities reported can be severe in the short term and these could be secondary to more invasive lesions and equipment used.

Programmed-cell death ligand 1 (PD-L1) expression in equine sarcoids and squamous cell carcinoma.

Background: Sarcoids and squamous cell carcinomas (SCCs) are the most concerning equine oncological diseases. Both tumors are challenging to manage due to their invasive behavior and high prevalence of recurrences. Furthermore, SCCs have a propensity to metastasize. Programed cell-death ligand 1 (PD-L1) has been one of the main therapeutic targets for immunotherapy in various human tumors. PD-L1 research in equine tumors is scarce and more efforts are necessary to understand the potential of this biomarker as a therapeutical target. Aim: Evaluate the immunohistochemical expression of PD-L1 in equine sarcoids and SCC. Methods: Thirteen equine tumors (seven sarcoids and 6 SCCs) were tested by immunohistochemistry and evaluated semi quantitatively to assess the percentage of positive cells. Results: None of the sarcoids presented PD-L1 expression. Regarding SCC, 2 tumors presented <10% of labeled cells; 2 tumors presented 10%-25% of labeled cells and 2 tumors presented 25%-50% of labeled cells. There were statistically significant differences between sarcoids and SCC regarding the expression of PD-L1. Conclusion: Our results point to the fact that PD-L1 could be a potential therapeutic target against SCC, and also encourage in-depth studies in this area, with larger sample sizes.

Equus caballus papillomavirus Type 7 is a rare cause of equine penile squamous cell carcinomas.

Penile squamous cell carcinomas (SCCs) are common, potentially life-threatening neoplasms of horses. They are well-recognized to be caused by Equus caballus papillomavirus (EcPV) type 2, although EcPV2 cannot be detected in all cases. A 23-year-old standardbred gelding developed multiple penile in situ and invasive SCCs that contained histological evidence of PV infection. By using both consensus and specific PCR primers, these lesions were found to contain EcPV7 DNA, but not DNA from EcPV2 or any other PV type. To determine how frequently EcPV7 is present in equine penile SCCs, specific primers were used to detect EcPV2 and EcPV7 in a series of 20 archived samples. EcPV7 was the only PV detected in one, both EcPV2 and 7 were detected in five, and only EcPV2 was detected in 14 SCCs. EcPV7 DNA was also detected in three of 10 archived oropharyngeal SCCs, although only as a co- infection with EcPV2. This is the first report of EcPV7 causing disease in horses. These results suggest EcPV7 could cause a subset of equine penile SCCs, and this is the first evidence that PV types other than EcPV2 can cause these neoplasms. The detection of EcPV7 in the oropharyngeal SCCs suggests a potential role of this PV type in the development of these SCCs. There were no clinical or histological features that differentiated lesions containing EcPV7 DNA from those containing EcPV2 DNA. If EcPV7 causes a proportion of equine penile SCCs, vaccines to prevent EcPV2 infection may not prevent all equine penile SCCs.

Oral cavity squamous cell carcinomas in zoo-managed Goeldi's monkeys (Callimico goeldii).

BACKGROUND: Oral cavity squamous cell carcinomas (OCSCCs) are relatively common in multiple non-human primate species but are poorly documented in Goeldi's monkeys. METHODS: Four Goeldi's monkeys with OCSCC, from three zoological collections, underwent necropsy with cytology, histopathology, immunohistochemistry, and pan-herpesvirus PCR analysis. RESULTS: All animals were euthanised and exhibited poor-to-emaciated body condition. Three OCSCCs arose from the maxillary oral mucosa and a single OCSCC was primarily mandibular, with bone invasion evident in three cases. Histologically, one OCSCC in situ was diagnosed, whilst the rest were typically invasive OCSCCs. Neoplastic cells were immunopositive for pancytokeratin and E-cadherin. All examined cases were negative for regional lymph node (RLN) and/or distant metastases, cyclooxygenase-2 (COX-2) immunoexpression, and panherpesvirus PCR expression. CONCLUSIONS: OCSCCs in Goeldi's monkeys may be deeply invasive, but not readily metastatic. No herpesvirus-association or COX-2 expression was evident; the latter suggesting that NSAIDs are unlikely to be a viable chemotherapeutic treatment.

Adjunctive bevacizumab therapy in an equine corneal stromal invasive squamous cell carcinoma with a 53-months follow-up.

A 17-year-old Appaloosa mare was referred for evaluation of presumed refractory keratitis of the left eye. Gross examination revealed ocular discomfort and corneal neovascularization with a nasal focal opacification affecting approximately 40% of the corneal surface. On ophthalmic examination, extensive subepithelial to mid-stromal vascular branching accompanied by a homogeneous white, dense opacification, which affected up to 80% of the total corneal thickness, were apparent. Signs of concurrent uveitis were absent. Deep-stromal lamellar keratectomy with a conjunctival pedicle graft was performed under general anesthesia. Histopathology confirmed a poorly differentiated corneal stromal invasive squamous cell carcinoma (SI-SCC) with neoplastic cell extension to the surgical margins. Postoperatively, 4 topical mitomycin C 0.04% chemotherapy cycles combined with oral firocoxib therapy were initiated. Seven months after surgery, regrowth of the SI-SCC was clinically suspected. A total volume of 1 ml bevacizumab 2.5% was administered in the standing sedated horse via 3 mid-stromal corneal injections. Four weeks later, intrastromal bevacizumab injections (ISBIs) were repeated, however, this time the solution was injected directly into the main corneal vessel branches.Seven weeks after the second ISBIs, the left eye was comfortable and significant remission of corneal vascularization and opacity was recognized. No recurrence has been noted for a follow-up period of more than 53 months.Equine SI-SCC usually has a very poor prognosis for globe maintenance. To the authors' knowledge this is the first report of well-tolerated intrastromal antivascular endothelial growth factor adjunctive therapy with bevazicumab 2.5% and SI-SCC resolution after a multimodal treatment approach.

Salivary metabolomic identification of biomarker candidates for oral melanoma and oral squamous cell carcinoma in dogs.

BACKGROUND: Oral melanoma (OM) and oral squamous cell carcinoma (OSCC) are frequently diagnosed in dogs, presenting a challenge in distinguishing them from benign oral tumors (BN). Salivary metabolomic biomarkers offer a practical solution because of saliva's direct contact with tumors and the noninvasive nature of collection. OBJECTIVE: Assess the diversity and abundance of the salivary metabolome in dogs with BN, OM, and OSCC using amine/phenol submetabolome analysis and high-performance chemical isotope labeling liquid chromatography-mass spectrometry (CIL LC-MS). ANIMALS: Study included 11 BN, 24 OM, 10 OSCC, and 20 healthy control dogs. METHODS: Case-control cross-sectional study was conducted to assess salivary submetabolic profiles in dogs with BN, OM, and OSCC and healthy dogs. Samples were labeled with 12C-dansyl chloride and analyzed using CIL LC-MS targeted to amine- and phenol-containing metabolites for amine/phenol submetabolome analysis. RESULTS: Distinct clusters and significant differences in metabolite concentrations were observed among the oral cancer, BN, and control groups. A total of 154 and 66 metabolites showed significantly altered concentrations, particularly in OM and OSCC, respectively, when compared with BN (Padj < .05). Potential metabolic biomarkers were identified for each cancer, including decreased concentrations of seryl-arginine and sarcosine in OSCC. Moreover, high-confidence putative metabolites were identified, including an increase in tryptophyl-threonine and a decrease in 1,2-dihydroxynapthalene-6-sulfonic acid and hydroxyprolyl-hydroxyproline for OM. CONCLUSIONS AND CLINICAL IMPORTANCE: We identified high coverage of the amine/phenol submetabolome, including seryl-arginine, and sarcosine, in OSCC. Our findings emphasize the potential of these biomarkers for distinguishing between oral OSCC and BN in dogs.

Characterization of the skin microbiome in normal and cutaneous squamous cell carcinoma affected cats and dogs.

Human cutaneous squamous cell carcinomas (SCCs) and actinic keratoses (AK) display microbial dysbiosis with an enrichment of staphylococcal species, which have been implicated in AK and SCC progression. SCCs are common in both felines and canines and are often diagnosed at late stages leading to high disease morbidity and mortality rates. Although recent studies support the involvement of the skin microbiome in AK and SCC progression in humans, there is no knowledge of this in companion animals. Here, we provide microbiome data for SCC in cats and dogs using culture-independent molecular profiling and show a significant decrease in microbial alpha diversity on SCC lesions compared to normal skin (P ≤ 0.05). Similar to human skin cancer, SCC samples had an elevated abundance of staphylococci relative to normal skin-50% (6/12) had >50% staphylococci, as did 16% (4/25) of perilesional samples. Analysis of Staphylococcus at the species level revealed an enrichment of the pathogenic species Staphylococcus felis in cat SCC samples, a higher prevalence of Staphylococcus pseudintermedius in dogs, and a higher abundance of Staphylococcus aureus compared to normal skin in both companion animals. Additionally, a comparison of previously published human SCC and perilesional samples against the present pet samples revealed that Staphylococcus was the most prevalent genera across human and companion animals for both sample types. Similarities between the microbial profile of human and cat/dog SCC lesions should facilitate future skin cancer research. IMPORTANCE: The progression of precancerous actinic keratosis lesions (AK) to cutaneous squamous cell carcinoma (SCC) is poorly understood in humans and companion animals, despite causing a significant burden of disease. Recent studies have revealed that the microbiota may play a significant role in disease progression. Staphylococcus aureus has been found in high abundance on AK and SCC lesions, where it secretes DNA-damaging toxins, which could potentiate tumorigenesis. Currently, a suitable animal model to investigate this relationship is lacking. Thus, we examined the microbiome of cutaneous SCC in pets, revealing similarities to humans, with increased staphylococci and reduced commensals on SCC lesions and peri-lesional skin compared to normal skin. Two genera that were in abundance in SCC samples have also been found in human oral SCC lesions. These findings suggest the potential suitability of pets as a model for studying microbiome-related skin cancer progression.

Gingival squamous cell carcinoma in 2 lions under managed care.

Neoplasia is one of the main causes of euthanasia in geriatric captive nondomestic felids. However, few studies have examined oral tumors in these animals. We describe here the clinicopathologic features of gingival squamous cell carcinoma (SCC) in 2 lions (Panthera leo) from separate zoologic collections. In both cases, the lions had a history of sialorrhea, bloody oral discharge, and anorexia. Autopsy findings in both lions were similar and were characterized by poorly circumscribed, friable, and bloody gingival masses with grossly apparent invasion of the mandibular bone; a pathologic fracture was observed in 1 case. Histologically, the masses consisted of poorly circumscribed, unencapsulated, densely cellular proliferations of neoplastic epithelial cells arranged in irregular islands, cords, and anastomosing trabeculae with formation of keratin pearls, which, coupled with positive immunohistochemistry for pancytokeratin, were diagnostic for SCC. Although no metastases were found in either animal, both lions were ultimately euthanized because of poor prognosis.

Expression of mPGES1 and p16 in feline and human oral squamous cell carcinoma: A comparative oncology approach.

Comparative cancer studies help us determine if discoveries in one species apply to another. Feline and human oral squamous cell carcinoma (FOSCC and HOSCC) are invasive tumours in which inflammation and abnormal p16 expression are reported. Immunohistochemistry was used to determine the expression of p16 and microsomal prostaglandin E2 synthase 1 (mPGES1) in 42 HOSCC and 45 FOSCC samples with known expression of cyclooxygenase 2 (COX2) and cluster of differentiation 147 (CD147). High p16 expression was more common in HOSCC tumour cells compared to adjacent stroma and oral epithelium (p < .05), with a similar but statistically nonsignificant pattern in FOSCC. Interestingly, high mPGES1 expression in FOSCC was more common in the adjacent epithelium compared to the other compartments (p < .05). In HOSCC, mPGES1 was more similar between compartments but was numerically more common in the tumour compartment (p > .05). There were nominal (p > 0.05) differences in marker expression between high and low mPGES1 expressing tumours in both species, including high p16 observed more commonly in high mPGES1 tumours, and COX-2 positive tumours being more common in low mPGES1 tumours. High CD147 HOSCC tumours were more common in the high mPGES1 HOSCC group (p < .05). In the FOSCC cohort, where there was no statistical difference in CD147 expression between high and low mPGES1 tumours, there were numerically higher CD147 cases in the high mPGES1group. Different expression patterns in FOSCC and HOSCC could be related to different risk factors. For example, p16 is a marker of papillomavirus-driven HOSCC, but a causal relationship between papillomaviruses and FOSCC has yet to be definitively demonstrated. The significance of high P16 expression in the absence of papillomavirus infection deserves further study, and the relative contributions of COX2 and mPGES1 to tumour inflammation and progression should be explored. The findings reveal potential similarities in FOSCC and HOSCC biology, while also demonstrating differences that may relate to risk factors and pathogenesis that are unique to each species.

Marginal resection and infracyanine green-mediated photodynamic therapy in the management of feline eyelid squamous cell carcinoma: Two cases.

OBJECTIVE: Describe the presenting features, surgical procedure, and clinical outcomes of two cats managed with marginal resection and photodynamic therapy (PDT) for eyelid squamous cell carcinoma (SCC). ANIMALS STUDIED: A 12-year-old female spayed domestic shorthair cat (case 1) and a 10-year-old female spayed domestic shorthair cat (case 2). PROCEDURES: Following marginal resection of the eyelid neoplasm, hemostasis was achieved using a handheld cautery unit then 1 mL of infracyanine green was injected into the surgical wound bed. Photodynamic therapy was performed using an 810 nm diode laser in two consecutive steps: (i) six cycles at 500 mW for 30 s per cycle, using a rapid movement; then (ii) one (case 1) or two cycles (case 2) of 30 s at 2000 mW, using a slow deliberate movement to effect (charred surface). RESULTS: Histopathology was consistent with SCC resected with incomplete margins in both cats. Follow-up duration was 416 and 161 days in case 1 and case 2, respectively. Consecutive exams and photo-documentation (in clinic or by owners) showed appropriate healing of the lower eyelid, with a smooth lid margin, and no evidence of tumor regrowth or ocular irritation. Subtle trichiasis was noted in case 1 on day 185, but not at the last follow-up. CONCLUSIONS AND CLINICAL RELEVANCE: Marginal resection followed by PDT may be a valid alternative to complete surgical resection of periocular SCC in cats. The procedure was easy to perform, post-operative recovery was uncomplicated, and neither cat developed recurrent disease during the follow-up period.

Intralesional interferon alpha-2b as a novel treatment for periocular squamous cell carcinoma in horses.

OBJECTIVE: To determine the safety and efficacy of perilesional human recombinant interferon alpha-2b (IFNα2b) for treatment of periocular squamous cell carcinoma (PSCC) in horses. ANIMALS STUDIED: Eleven horses (12 eyes) with PSCC were enrolled in this prospective clinical study with owner consent. PROCEDURES: Systemically healthy horses were included in the study following confirmation of PSCC via biopsy. Every two weeks for a maximum of six treatments, horses were sedated and perilesional injection of IFNα2b (10 million IU) was performed. Tumors were measured prior to each injection and at one, three, and 12 months after treatment completion. A greater than 50% reduction in tumor size was considered positive response to treatment (i.e., partial or complete response). Development of anti-IFNα2b antibodies was assessed using serum samples obtained after treatment initiation and compared with treatment responses. Antibody concentrations were analyzed using a mixed model. Statistical significance was considered p < 0.05. RESULTS: Each horse received four to six perilesional injections of IFNα2b. Five of 12 eyes (4/11 horses) responded to treatment. Two of five eyes showed complete resolution of gross PSCC. No systemic adverse effects were seen. Local swelling occurred during treatment protocol in 6/11 horses but resolved without intervention. All horses developed serum anti-IFNα2b antibodies. There was no evidence of statistical difference in antibody concentration between responders and non-responders. CONCLUSIONS: Perilesional administration of IFNα2b was found to be well-tolerated in horses with PSCC, and induced tumor regression in 42% of treated eyes. Treatment failure appears unrelated to the development of IFNα2b antibodies.

Equus caballus papillomavirus type 2 (EcPV2)-associated benign penile lesions and squamous cell carcinomas.

BACKGROUND: Squamous cell carcinoma is the most common genital, ocular and gastric tumour in horses. Equus caballus papillomavirus type 2 (EcPV2) DNA has been detected in several studies in equine penile squamous cell carcinomas (SCCs) and precursor lesions providing evidence of a causal role of EcPV2 in equine genital SCCs. Recently, EcPV2 E6/E7 nucleic acids were also detected in equine gastric SCCs, but further studies are required to determine the role of EcPV2 infection in the pathogenesis of gastric SCC. EcPV2 nucleic acids have been rarely described in ocular SCCs and precursor lesions. OBJECTIVES: To investigate the presence of EcPV2 nucleic acids with polymerase chain reaction (PCR) and in situ hybridisation (ISH) in penile hyperplasias, papillomas and SCCs in horses and to determine whether EcPV2 nucleic acids can be detected in SCCs affecting other locations, including the stomach, ocular tissues and larynx. METHODS: Twenty-one archival formalin-fixed paraffin embedded (FFPE) tissue samples, including 12 genital lesions comprising penile hyperplasias, papillomas and SCCs, 6 ocular SCCs, 2 gastric SCCs and 1 laryngeal SCC, were screened by PCR and ISH for EcPV2 E6/E7 DNA and mRNA. Archival FFPE tissue samples (eyelid and penile mucosa and preputium) from six horses without a diagnosis or history of neoplastic or papillomavirus-associated disease were included as controls. RESULTS: EcPV2 nucleic acids were detected by PCR and ISH in all genital lesions (12/12) and gastric SCCs (2/2), in two ocular SCCs (2/6) and in one laryngeal SCC (1/1). In control horses, one eyelid sample was positive in PCR but not in ISH. The remaining control samples were negative for EcPV2 E6/E7 nucleic acids in PCR and ISH. CONCLUSIONS: These results further support the role of EcPV2 infection in the development of equine genital SCCs and suggest that EcPV2 infection may also act as a predisposing factor for other SCCs in horses, including gastric, ocular and laryngeal SCCs.

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.

The effect of feeding a commercial feedstuff on gastric squamous gastric disease (ESGD) healing and prevention of recurrence.

Feedstuffs are often recommended to mitigate potential damage from acid associated with equine squamous gastric disease (ESGD). In acidic conditions, pectin alters its structure to one like mucus and binds the stomach mucosa, whilst alfalfa has a strong intrinsic acid buffering capacity. The study aimed to determine whether feeding a commercial beet pulp/alfalfa/oat fibre mix aids ESGD healing and/or prevention of recurrence. Ten adult horses with naturally occurring ESGD were included. All animals were treated with omeprazole as per the attending veterinarian's recommendation and randomly allocated to also be fed a commercial beet pulp/alfalfa/oat fibre mix (1Kg/horse divided into 2 meals/day; n=5) or no additional feed (n=5) for one month. Gastroscopy was then repeated to assess response to therapy. If the ESGD had healed, omeprazole therapy was discontinued, and the commercial feed given to all horses for a further month. Gastroscopy was repeated to determine ESGD recurrence. The mean (±SD) age of the horses was 11.6 (±3.8) years; 4 mares and 6 geldings; various breeds were represented; and the median (range) initial ESGD grade was 2 (2-4). ESGD had healed (grade 0/4) in all animals after one month. After a further month, ESGD had recurred in significantly (p=0.04) more animals that did not receive the commercial feed initially (3/5; 60%; mean [range] ESGD grade 3 [0,4]) compared to those that did (0/5; 0%; mean [range] ESGD grade 0 [0,0]). Thus, the commercial beet pulp/alfalfa/oat fibre mix aided prevention of ESGD recurrence when fed during the healing and prevention phases.

Claw bed inverted squamous papilloma associated with canine papillomavirus type 2 in a dog.

A claw bed inverted squamous papilloma (ISP) presented clinically as a swollen digit in a dog. Canine papillomavirus (CPV) type 2 was amplified by PCR and localised to the papilloma's epidermis using in situ hybridisation. This is the first report demonstrating a claw bed ISP caused by CPV.

Un papillome squameux inversé de la matrice unguéale est décrit cliniquement comme un gonflement du doigt chez un chien. Le papillomavirus canin (CPV) de type 2 a été amplifié par PCR et localisé dans l'épiderme du papillome par hybridation in situ. Il s'agit du premier rapport faisant état d'un papillome squameux inversé de la matrice unguéale par le CPV.

Um caso de papiloma escamoso invertido no leito ungueal em um cão apresentando aumento de volume em um dígito. O vírus do papiloma canino (CVP) Tipo 2 foi amplificado por PCR e localizado na epiderme do papiloma utilizando hibridização in situ. Este foi o primeiro relato demonstrando um papiloma escamoso invertido causado por CPV.

Un papiloma escamoso invertido del lecho ungueal se presentó clínicamente como un dedo hinchado en un perro. Se amplificó mediante PCR genoma del virus papiloma canino tipo 2 (CPV) y se localizó en la epidermis el papiloma mediante hibridación in situ. Este es el primer reporte de caso que demuestra la existencia de un papiloma escamoso invertido del lecho ungueal causado por CPV.