Tumours In Horses Research Articles

Bovine papillomavirus gene expression and inflammatory pathway activation vary between equine sarcoid tumour subtypes

Equine sarcoids are common non-metastasising skin tumours in horses, associated with bovine papillomavirus (BPV) infection. Six subtypes are recognised (occult, verrucose, nodular, fibroblastic, mixed and malevolent lesions), with variable clinical behaviour. The pathophysiology underlying varying tumour phenotype is poorly understood, and previous data on associations with viral load have been conflicting. To better understand this clinical variation, we investigated associations between tumour subtype and viral load, viral early protein gene expression, and expression of 10 host genes by quantitative polymerase chain reaction in 27 sarcoids and 5 normal skin samples. Viral DNA copy number did not differ between subtypes but was significantly higher in animals with fewer tumours. Expression of BPV E2 and E6 was higher in occult lesions compared to fibroblastic or nodular lesions, while E5 expression was higher in previously-treated lesions. Of the host genes, only IL6 and IL1B differed between subtypes, with higher expression in fibroblastic lesions, while IL10 and CCL5 were elevated compared to skin in all lesion types, and elevations in TNF and TGFB1 were significant for occult lesions only. Expression of TLR9, ATR, VEGFA and PTGS2 in sarcoids was not significantly different from normal skin, suggesting differences between BPV and human papillomavirus tumorigenesis. Results for BPV viral load and gene expression differed from previous reports and are insufficient to explain the spectrum of tumour phenotypes. Activation of both pro-inflammatory and anti-inflammatory immune pathways in sarcoids could influence tumour growth and effective immune responses, and the contribution of specific infiltrating immune cells requires further investigation.

Impact of Equine Ocular Surface Squamous Neoplasia on Interactions between Ocular Transcriptome and Microbiome.

Ocular surface squamous neoplasia (OSSN) represents the most common conjunctival tumor in horses and frequently results in vision loss and surgical removal of the affected globe. Multiple etiologic factors have been identified as contributing to OSSN progression, including solar radiation exposure, genetic mutations, and a lack of periocular pigmentation. Response to conventional treatments has been highly variable, though our recent work indicates that these tumors are highly responsive to local immunotherapy. In the present study, we extended our investigation of OSSN in horses to better understand how the ocular transcriptome responds to the presence of the tumor and how the ocular surface microbiome may also be altered by the presence of cancer. Therefore, we collected swabs from the ventral conjunctival fornix from 22 eyes in this study (11 with cytologically or histologically confirmed OSSN and 11 healthy eyes from the same horses) and performed RNA sequencing and 16S microbial sequencing using the same samples. Microbial 16s DNA sequencing and bulk RNA sequencing were both conducted using an Illumina-based platform. In eyes with OSSN, we observed significantly upregulated expression of genes and pathways associated with inflammation, particularly interferon. Microbial diversity was significantly reduced in conjunctival swabs from horses with OSSN. We also performed interactome analysis and found that three bacterial taxa (Actinobacillus, Helcococcus and Parvimona) had significant correlations with more than 100 upregulated genes in samples from animals with OSSN. These findings highlight the inflammatory nature of OSSN in horses and provide important new insights into how the host ocular surface interacts with certain microbial populations. These findings suggest new strategies for the management of OSSN in horses, which may entail immunotherapy in combination with ocular surface probiotics or prebiotics to help normalize ocular cell and microbe interactions.

Papillomavirus-like Particles in Equine Medicine.

Papillomaviruses (PVs) are a family of small DNA tumor viruses that can induce benign lesions or cancer in vertebrates. The observation that animal PV capsid-proteins spontaneously self-assemble to empty, highly immunogenic virus-like particles (VLPs) has led to the establishment of vaccines that efficiently protect humans from specific PV infections and associated diseases. We provide an overview of PV-induced tumors in horses and other equids, discuss possible routes of PV transmission in equid species, and present recent developments aiming at introducing the PV VLP-based vaccine technology into equine medicine.

Retrobulbar tumours in horses with the leading symptom exophthalmus – 11 cases from 2016 to 2021

Retrobulbar tumours in horses with the leading symptom exophthalmus – 11 cases from 2016 to 2021

Evaluation of larval therapy effects on the progression of equine sarcoid

Background: The skin is the largest organ of the body and is of particular importance in the beauty and economic value of the horse. Equine sarcoid disease (ESD) is the most common skin tumor in horses. So far, various methods have been used to treat sarcoidosis, but no fully effective treatment has yet been proposed. The use of larval therapy in the treatment of human diabetic ulcers and horse hoof lesions is spreading. Reports of the use of larval therapy to treat the complications of tumor lesions have been promising.Objectives: This study was performed to evaluate the effect of larval therapy on equine sarcoid lesions. Methods: In this study, 4 cases were diagnosed with sarcoid by clinical examinations and pathological tests, and larval therapy was used to treat sarcoid lesions. To place the larvae on the lesion, the method of implantation in an artificial nest was used. The number of larvae used per square centimeter was about 10 larvae. Result: The result of treatment was satisfactory in 2 cases of horses and even in one case the lesion was largely limited and the emergence of healthy skin began. In the other two cases, no positive result was seen, which was probably due to the extent of the lesion and the instability of the larvae on it. Conclusions: According to the obtained results, it seems that larval therapy is effective for the treatment of sarcoid necrotic lesions, but more studies are needed in this field.

Equine Carcinoma Hemithyroidectomy

Background: In horses, the thyroid gland is located slightly caudal to the larynx and dorsolaterally between the third and sixth tracheal ring, adjacent to the thyroid, there are four small glands called parathyroid glands. In the clinical routine of horses, thyropathies are difficult to be diagnosed, as they have a silent evolution. Thyroid neoplasia is the most common finding in horses, usually unilateral and normally present in older animals. The present study reports a case of equine thyroid carcinoma and its systemic clinical effects, which was successfully treated by means of hemitieroidectomy. Case: A 12-year-old male mixed breed horse weighing 436 kg, was admitted to the Veterinary Medical Teaching Hospital of the FZEA/USP with the main complaint of volume increase in the right ventrolateral region of the neck, difficulty in swallowing, significant weight loss and weakness of the pelvic limbs. On inspection, there was an increase in volume in the topographic region of the thyroid gland and on palpation, there was a firm mass, with delimited edges, with a smooth, mobile surface, without increasing the temperature and without pain. The animal was sent for ultrasound examination, which revealed a delimited mass, with an apparent capsule around it, differentiated and disorganized cellularity with small hypoechoic points of liquid inside the structure, with no apparent vascularization inside the mass. These findings, associated with the anatomical location of the mass, were consistent with thyroid tissue. The clinical signs commonly observed in thyroid neoformations are respiratory stridor, decreased performance, difficulty in swallowing and suffocation. As there was a compromised diet and weight gain, as well as athletic performance, he chose to have a hemithyroidectomy. After surgery, histopathology of the tissue was performed and thyroid carcinoma was diagnosed. Postoperatively, the animal was medicated with antibiotics, anti-inflammatory and anti-tetanus serum, after 10 days the stitches were removed and the animal was discharged. Discussion: Neoplasia is the most frequent cause of progressive thyroid growth and in case of suspicion of thyroid disorders, thin needle aspiration (FNAB) is recommended and, later, histopathological examination, which is considered the gold standard for diagnosis pathologies of the thyroid gland. In the present case, no FNAB or preoperative histopathological examination was performed due to the time required to obtain the result, associated with difficulty in swallowing and significant weight loss, which required immediate removal of the mass. Considering that the ultrasound examination revealed the absence of noble structures or important vascularization very close to or adhered to the mass, its removal prior to the histopathological examination was indicated. As there was compromised feeding and weight gain, he opted for hemithyroidectomy, the recommended treatment for unilateral tumors in horses. When performing a hemithyroidectomy, it should be remembered that the parathyroid glands accompany the thyroid and are located in its posterior portion, in the pre tracheal region, with its variable final position. With this variation in topography, the identification of parathyroid glands becomes challenging and, consequently, after thyroidectomy, a portion of parathyroid glands stops operating, and this fact is marked clinically by hypocalcemia and its consequences. In this case described, in which the animal had a tumor in thyroid tissue, possibly the parathyroid functions were also altered, which probably reflected in the lameness in the pelvic limbs. It is concluded that partial hemithyroidectomy in horses is an easy procedure to perform and has favorable results in relation to prognosis and quality of life. Keywords: carcinoma, hemithyroidectomy, thyroid. Título: Hemitireoidectomia por carcinoma em equinoDescritores: carcinoma, hemitireoidectomia, tireóide.

The oncogenic pathways of papillomaviruses.

Papillomaviruses are oncogenic DNA viruses and induce hyperplastic benign lesions of both cutaneous and mucosal tissues in their various hosts, including many domestic and wild animals as well as humans. There are some Papillomavirus genotypes that can infect hosts different from their own, such as BPV 1 and BPV 2 originated from cattle, which can also infect horses and are responsible for fibroblastic tumours in horses. This review article summarizes the origin and evolution of papillomaviruses as an etiological agent in the historical process. The main focus in this review is the evaluation of the interactions between high-risk papillomavirus oncoproteins and programmed cell-death pathways. It further exemplifies the role of these interactions in the malignant cell transformation process. In parallel with this, the use and importance of the bovine model system to enlighten the papillomavirus-associated cancers is discussed with an in-depth examination. Furthermore, it focuses on the epidemiological situation of BPV infections in Turkey in the cattle herds.

Use of the Intratumoural Anticancer Drug Tigilanol Tiglate in Two Horses

Tigilanol tiglate is a novel small molecule approved as a veterinary pharmaceutical in Europe for intratumoural treatment of non-metastatic, non-resectable canine mast cell tumors. The drug has a “tumor agnostic” mode of action associated with induction of an acute inflammatory response at the treatment site, immune cell recruitment, and disruption of tumor vasculature. Consequently, tigilanol tiglate has potential in treating a range of tumor types in humans and companion animals. However, it is likely that species-specific dosing and concomitant medication protocols will be required, especially to manage the drug-induced acute inflammatory response at the treatment site. As an initial step in evaluating tigilanol tiglate for treating cutaneous tumors in horses, we developed an equine-specific protocol involving (a) a 30% reduction in intratumoural tigilanol tiglate dose rate compared to that used in dogs, and (b) a regime of concomitant medications to manage the drug-induced acute inflammatory response at the treatment site. Here we report a preliminary study in two horses using the protocol to treat (i) an aggressive fibroblastic sarcoid that had recurred following surgical excision and (ii) a fast-growing peri-ocular squamous cell carcinoma. Clinical response to tigilanol tiglate treatment in these cases was similar to that observed in canine and human patients. Localized inflammation and bruising developed rapidly at the treatment site with haemorrhagic necrosis of the tumor evident within 24 h. Slough of necrotic tumor mass occurred within 6–16 days followed by infill of the tissue defect and full re-epithelialisation of the treatment site with good functional outcome. Drug-induced inflammation and oedema at the treatment site were well controlled by the concomitant medications and largely resolved within 3 days, while the wound that formed following tumor slough healed uneventfully. Both patients displayed minor lethargy during the first 36 h after treatment and localized treatment-site discomfort was apparent over the first 3–5 days. There was no evidence of recurrence of the sarcoid at 93 days, or the squamous cell carcinoma at 189 days. The results from this study support continued development and evaluation of tigilanol tiglate as a potential future treatment option for cutaneous equine tumors.

Evaluation of Locally Injected Mycobacterium Cell Wall Fraction in Horses with Sarcoids

A reformulation of Mycobacterium cell wall fraction immunotherapeutic can be used to successfully treat sarcoids in horses. Sarcoids are reported to be the most common equine skin tumors with tumor type and location influencing the choice of treatment. Wide surgical excision is curative for many tumors, but may not always be feasible. Previous studies have reported sarcoid regression after injection with mycobacterial cell wall immunotherapeutics. A new formulation of the Mycobacterium phlei cell wall fraction immunostimulant (Immunocidin Equine) was used to treat cutaneous tumors in horses. Equids with skin tumors diagnosed as sarcoids were enrolled in the study. Sarcoids were injected at the initial visit with Immunocidin Equine and subsequently at approximately 2-week intervals. Of 17 cases, nine cases were completely resolved at the end of the study period evaluation or at the time of final follow-up (52.9%). Three cases were reported as improved (smaller), but not resolved (17.6%). Three cases were discontinued from the study as the respective masses were growing larger or not resolving (17.6%). One case (5.8%) with two masses had resolution of one mass, whereas the other tumor had a small regrowth 5 months after the last treatment. One case (5.8%) was lost to follow-up. All cases had mild to moderate swelling of the injection site, and some cases had discharge after the second, third, or fourth injections. No serious systemic side effects or complications were encountered during the study.

Abstract B33: Immuno gene therapy with IL-12 combined with electrochemotherapy for the treatment of skin and oral tumors in client-owned dogs

Abstract Cancer is a common disease of client-owned dogs, with the majority of solid tumors located in the skin or oral cavity. One of the local ablative therapy is electrochemotherapy, where cytotoxic drugs, bleomycin or cisplatin, are introduced into the cells by application of electric pulses (electroporation). In veterinary oncology, electrochemotherapy proved to be an effective and safe local treatment of tumors in horses, cats, dogs, and exotic animals, where success is comparable to standard surgical therapy. The drawback of electrochemotherapy is that, despite its high local effectiveness, it does not have systemic antitumor effects. In preclinical and some clinical studies, gene electrotransfer (GET) of plasmid encoding IL-12 was effective local therapy eliciting also systemic immune response. By means of electroporation, the plasmid DNA is introduced into the cells, resulting in IL-12 expression. The aim of our study was to evaluate a combination of electrochemotherapy and GET of plasmid encoding canine IL-12 for the treatment of skin and oral tumors in dogs. From June 2015 till October 2018, 51 dogs were enrolled in the clinical study: 38 dogs with 68 skin tumors and 13 dogs with oral tumors. Under general anesthesia, electrochemotherapy and gene therapy with IL-12 were performed. For electrochemotherapy cytotoxic drugs were first administered: bleomycin intravenously or intratumorally or cisplatin intratumorally. Standard electrochemotherapy pulses (8 electric pulses, 100 μs, 1300 V/cm, 5 kHz) were applied 10 minutes after intravenous bleomycin administration and immediately after intratumoral bleomycin or cisplatin administration. After electrochemotherapy, the plasmid pCMVcaIL-12 was applied peritumorally at two sites of the tumor and immediately after application of plasmid DNA the electric pulses were applied, using noninvasive electrodes with 7 pins arranged in hexagonal arrays with central pin (24 pulses, 60 V, 150 ms, 0.40/1.39 Hz). The results of our study showed that the combination of electrochemotherapy and gene therapy of plasmid IL-12 is the most effective in treatment of skin tumors, especially in the case of mast cell tumors, with ~90% of local tumor control rate. Moreover, in the case of skin tumors we demonstrated an effect in distant untreated tumors in 5 dogs, which confirms the systemic (abscopal) effect of the therapy. In the treatment of oral tumors, we achieved 54% of objective local tumor response 1 month after treatment. Although progressive disease occurred in 11/13 patients at the end of observation period, a mean survival time of 7 months was obtained, which is comparable with standard surgical therapy, but without cosmetic or functional shortcomings that occur after surgical treatment. To conclude, the results of our study showed significant antitumor response of combined therapy in the case of skin tumors. Also, for dogs with oral tumors combined therapy represents a valuable treatment option, especially when other treatment approaches are not applicable or acceptable. Citation Format: Maja Cemazar, Ursa Lampreht Tratar, Nina Milevoj, Andreja Brozic, Ana Nemec, Gregor Sersa, Natasa Tozon. Immuno gene therapy with IL-12 combined with electrochemotherapy for the treatment of skin and oral tumors in client-owned dogs [abstract]. In: Proceedings of the AACR Special Conference on Tumor Immunology and Immunotherapy; 2019 Nov 17-20; Boston, MA. Philadelphia (PA): AACR; Cancer Immunol Res 2020;8(3 Suppl):Abstract nr B33.

Melanocytic tumours in horses

Melanocytic tumours in horses

Expression of vascular endothelial growth factor (VEGF) in equine sarcoid

BackgroundSarcoids are the mostcommon skin tumors in horses, characterized by rare regression, invasiveness and high recurrence following surgical intervention and Delta Papillomaviruses are widely recognized as the causative agents of the disease. In order to gain new insights into equine sarcoid development, we have evaluated, in 25 equine sarcoids, by immunohistochemistry and western blotting analysis, the expression levels of VEGF, Ki67 and bcl-2. Moreover, we have measured microvessel density and specific vessel parameters.ResultsAll sarcoid samples showed a strong and finely granular cytoplasmatic staining for VEGF in the majority (90%) of keratinocytes, sarcoid fibroblasts and endothelial cells. Numerous small blood vessels, immunostained with Von Willebrand factor, often appeared irregular in shape and without a distinct lumen, with mean values of microvessel area and perimeter lower than normal. Moreover, in all sarcoid samples, Ki67 immunoreactivity was moderately positive in 5–10% of dermal sarcoid fibroblasts, while Bcl2 immunoreactivity was detected in 52% of the sarcoid samples, with a weak staining in 20–50% of dermal sarcoid fibroblasts. Biochemical analysis was consistent with immunohistochemical results.ConclusionsThis study has provided evidence that in equine sarcoid: VEGF was strongly expressed; the increased number of vessels was not associated with their complete maturation, probably leading to a hypoxic condition, which could increase VEGF synthesis; the levels of sarcoid fibroblasts proliferation were very low. Concluding, VEGF may have a role in equine sarcoid development, not only through the increase of angiogenesis, but also through the control of sarcoid fibroblast activity.

Histocytic-like Atypical Mast Cell Tumours in Horses

This report describes a series of four equine mast cell tumours (MCTs) with atypical morphological features. The tumours were 1-2cm in diameter and mostly localized to the eyes (one eyelid, two conjunctiva). Histologically, they were composed of very large (up to 35μm) round pleomorphic cells with a large central to paracentral nucleus and abundant granular cytoplasm. A large number of viable mature eosinophils were detected intermingled with the large round cells. Histochemical staining (toluidine blue and Perls' Prussian blue) and immunohistochemistry (KIT, mast cell tryptase, lysozyme and proliferating cell nuclear antigen) confirmed the mast cell origin of the atypical cells and identified an aberrant KIT protein expression in three cases. Based on morphological and immunohistochemical features, we propose to call the lesions equine histiocytic-like atypical MCTs.

Sarcóide recidivante em glande de um equino: Relato de caso

Sarcoids are fibroblast and non-metastatic skin tumors, representing the most common tumors in horses. Its etiopathogenesis is related to bovine papillomavirus type 1 and type 2 infections, being the transmission and dissemination to other parts of the body of the same animal associated with bites, friction, fomites and insects. Clinical behavior is locally aggressive due to infiltrative capacity, as well as being refractory to different forms of therapies. The sarcoids are classified in six forms according to their clinical presentations, being these: hidden, verrucous, nodular, fibroblastic, mixed and malignant. The objective of this study is to report a clinical case of recurrent sarcoid in the equine glans, attended at the equine clinic of the Centro de Desenvolvimento da Pecuária of the Universidade Federal da Bahia, located in the municipality of Santo Amaro – BA. In the present case, an equine presented a tumor mass in the region of the glans, where a mass examination and histopathological examination were carried out; characteristics compatible with the sarcoid were observed. After five months of surgical intervention, the sarcoid presented recurrence with treatment instituted with an association between partial penectomy, ointment based on acyclovir 5% and autohemotherapy.

Tumours in equines, swine and camelids

The incidence of tumour occurrence has been increased in the last decade and is continuously increasing in the present days. This increase in the occurrence of the tumour can be attributed to the change in the biotic and abiotic environment due to pollutants which are favouring the tumour development by causing damage to the genetic material of the cells exposed to these pollutants. Occurrence of tumours in equines is frequently observed but their reports are very few. This report is an attempt to collect and provide details regarding tumours in equines based on the available records during the period 1990–2017. The tumours that were reported in equines are squamous cell carcinoma, sarcoids, seminoma, melanoma and cavernoma. In swine and camel, fibrosarcoma and squamous cell carcinoma was reported. Among this in horses, the squamous cell carcinoma has the highest occurrence followed by sarcoid, melanoma and seminoma. Data also indicates that skin tumours in horses are more common in comparison with the tumours of other organs.

Apocrine sweat gland ductal carcinoma in a 5-year-old Arabian stallion

Apocrine sweat gland carcinomas are very rare skin tumors in horses. A 5-year-old Arabian stallion was presented with a mass in the pastern region of the left forelimb. Grossly, a hairless and ulcerative mass measuring approximately 1 × 1 cm was noted. Complete surgical excision with wide, clean margins was selected as a method of treatment. Histopathological examination of the excised mass identified the apocrine sweat gland ductal carcinoma. There was no evidence of local tumor recurrence during the subsequent follow-up evaluations.

Surgical excision of large melanocytic tumours in grey horses: 38 cases (2001–2013)

SummaryMelanocytic tumours are common in grey horses. Large tumours can obstruct the rectum, or prepuce, inhibit food intake and impinge upon the upper airway. Surgical excision is locally curative, but is controversial for large or confluent tumours. Limited information on outcome following surgical excision of large melanomas is available. The objective of this study was to report outcome following surgical excision of large (≥4 cm) melanocytic tumours in horses. Our hypothesis was that surgical excision of large (≥4 cm) single and coalescing melanomas would be locally curative. Medical records were reviewed and cases that underwent excision of a single or coalescing melanoma, with at least one lesion ≥4 cm in diameter, included. Follow‐up information was obtained a minimum of 12 months post‐surgery from owners and referring veterinarians via telephone interviews, questionnaire, or direct examination. A total of 48 cases were identified; 38 horses with follow‐up were included in the study. Tumours involved the parotid, perianal or mid‐cervical regions, ventral tail base, prepuce, penis, ear, or thoracic inlet. There were no cases of tumour regrowth following excision. Post‐operative complications occurred in five cases and were easily resolved in all but one. Continued or new growth of distant melanocytic tumours occurred in 50% of cases. Results suggest that excision of large melanocytic tumours in horses is a viable treatment option that is locally curative with minimal complications.

Atypical Histocytic-like Mast Cell Tumours in Horses

Atypical Histocytic-like Mast Cell Tumours in Horses

Electrochemotherapy as a single or adjuvant treatment to surgery of cutaneous sarcoid tumours in horses: a 31-case retrospective study

The aim of our study was to evaluate the efficacy of electrochemotherapy (ECT) with cisplatin as a single or adjuvant treatment for sarcoids in equids. Different treatment options with different...

Bovine Papillomavirus DNA and S100 Profiles in Sarcoids and Other Cutaneous Spindle Cell Tumors in Horses.

Histopathologic differentiation between deep dermal or subcuticular equine sarcoids (ie, nodular sarcoids) and other spindle cell tumors in the dermis and subcutis such as peripheral nerve sheath tumors (PNSTs) can be challenging based on morphologic criteria alone. It has been proposed that polymerase chain reaction (PCR) for bovine papillomavirus (BPV) DNA and S100 immunohistochemistry be used as diagnostic tests to separate equine sarcoids from PNSTs. We reviewed 197 skin-associated spindle cell tumors (ie, soft tissue sarcomas), including PNSTs and sarcoids, received at the University of Florida between 1995 and 2013 and performed BPV PCR and S100 immunohistochemistry on archived paraffin-embedded tissues. We found that BPV DNA was demonstrable in 70% of the sarcoids, 59% of the PNSTs, 37% of the fibrosarcomas, and 22% of other tumors (myxosarcomas, fibromas, and other sarcomas) diagnosed on histomorphologic characteristics. Positive S100 staining was only seen in 12 tumors in the study (5 fibrosarcomas, 3 sarcoids, 2 PNSTs, and 2 other sarcomas). The results demonstrate that BPV is associated with many skin-associated spindle cell soft tissue tumors in horses in addition to sarcoids. S100 was rarely expressed in equine soft tissue sarcomas in the skin but was expressed in many tumor types, including PNSTs and sarcoids. Because 41% of the PNSTs classified by histomorphology in this study were BPV negative and 94% were S100 negative, it is reasonable to classify these as soft tissue sarcomas with nerve sheath tumor histomorphology rather than as either PNSTs or sarcoids.