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Topic:Cancer
Cancer in horses encompasses a range of neoplastic diseases that affect various tissues and organs in equine species. These conditions involve the uncontrolled growth of abnormal cells, which can form tumors and potentially spread to other parts of the body. Common types of cancer in horses include sarcoids, squamous cell carcinoma, and melanoma, each with distinct characteristics and clinical presentations. Diagnosis often involves a combination of physical examination, imaging techniques, and histopathological analysis. Treatment options vary based on the type and stage of cancer and may include surgical intervention, chemotherapy, and radiation therapy. This page compiles peer-reviewed research studies and scholarly articles that explore the epidemiology, pathophysiology, diagnostic methods, and treatment strategies for cancer in horses.
Selection of a set of reliable reference genes for quantitative real-time PCR in normal equine skin and in equine sarcoids. Real-time quantitative PCR can be a very powerful and accurate technique to examine gene transcription patterns in different biological conditions. One of the critical steps in comparing transcription profiles is accurate normalisation. In most of the studies published on real-time PCR in horses, normalisation occurred against only one reference gene, usually GAPDH or ACTB, without validation of its expression stability. This might result in unreliable conclusions, because it has been demonstrated that the expression levels of so called "housekeeping genes" may vary considerably in different t...
Survey of equine cutaneous neoplasia in the Pacific Northwest. A retrospective study examined data regarding equine cutaneous and mucocutaneous neoplasms submitted to the Veterinary Diagnostic Laboratory at Oregon State University in a 3.5-year period. A total of 536 neoplasms were identified, accounting for 30% of the total equine pathology submissions. Sarcoid, squamous cell carcinoma, melanocytic tumors, papillomas, and mast cell tumors were the most common neoplasms, constituting 87.5% of all cutaneous neoplasms. Sarcoids represented 51.4% of all neoplasms and 15.18% of total equine accessions. Sarcoid was most common in paints, quarter horses, and Ar...
The efficacy of intratumoural 5-fluorouracil for the treatment of equine sarcoids. To document the efficacy of intratumoural injections of 5-fluorouracil for the treatment of equine sarcoids. Methods: A prospective study that included 13 horses and one donkey. Methods: Sarcoids were confirmed by histological examination and treated with intratumoural 5-fluorouracil every 2 weeks. If the sarcoids did not resolve after seven treatments, treatment was considered a failure. All cases were re-examined 6 months after treatment commenced and owners were telephoned 3 years after commencement of treatment to report on tumour recurrence. Outcome comparisons were performed to determine...
The use of mitomycin C as an adjunctive treatment for equine ocular squamous cell carcinoma. To assess the effectiveness of topical mitomycin C application as an alternative adjunctive therapy to CO2 laser ablation in the treatment of equine ocular squamous cell carcinoma. Methods: A retrospective clinical study of eight client owned horses in which 10 affected eyes were treated for ocular squamous cell carcinoma over a 17 month period. (March 2003 to August 2004). Methods: Each horse was given a general anaesthetic to allow CO2 laser ablation of the lesion(s). Mitomycin C at a concentration of 0.4 mg/mL was then applied intraoperatively to the affected areas for 1 or 5 minutes. Posto...
Treatment of an ocular squamous cell carcinoma in a stallion with atrial fibrillation. A stallion was presented for surgical treatment of limbal squamous cell carcinoma. Excision with a conjunctival pedicle flap was done to prevent ocular invasion and preserve vision. A complication was the diagnosis of atrial fibrillation, which was not converted to sinus rhythm due to the potential complication of treatment with quinidine sulfate. Traitement d’un carcinome épidermoïde oculaire chez un étalon atteint de fibrillation auriculaire. Un étalon a été présenté pour une chirurgie d’un carcinome épidermoïde limbique. Après l’excision, un lambeau à pédicule conjonctiva...
Misregulated Wnt/beta-catenin signaling leads to ovarian granulosa cell tumor development. Misregulation of the Wnt/beta-catenin signaling pathway is a hallmark of several forms of cancer. Components of the Wnt/beta-catenin pathway are expressed in ovarian granulosa cells; nevertheless, its potential involvement in granulosa cell tumorigenesis has not been examined. To this end, human (n = 6) and equine (n = 18) granulosa cell tumors (GCT) were analyzed for beta-catenin expression by immunohistochemistry. Unlike granulosa cells of normal ovaries, most (15 of 24) GCT samples showed nuclear localization of beta-catenin, suggesting that activation of the Wnt/beta-catenin pathway plays ...
The influence of 1-10 kD fraction from brains of the hibernating ground squirrel and the Yakut horse on proliferation and protein synthesizing system of Ehrlich ascitic carcinoma cells. The experimental data presented in the work testify to the cytostatic activity of 1-10 kD polypeptide fractions from brains of the hibernating ground squirrel and the Yakut horse towards Ehrlich ascitic carcinoma (EAC) cells. The experiments on the investigation of the inhibiting influence of 1-10 kD fractions from tissues of the hibernating and cold-adapted animals on protein-synthesizing system of EAC cells allow us to conclude that the cytostatic effect of the fractions is effected at the genetic level in the tumor cells.
2nd FY Khoo Memorial Lecture. Brachytherapy–one man’s meat, a personal journey in radiation oncology. The Lecture covers the author's personal experience in brachytherapy in radiation oncology, beginning with low-dose rate (LDR) treatments using 226Ra "hot" sources, in the 1960s and early 1970s, through manual afterloading for treating gynaecological cancers with the same sources in the 1970s and 1980s, to high-dose rate (HDR) remote afterloading on a microSelectron HDR machine, from 1989 on. This progression in brachytherapy is discussed, and specific applications to various tumour sites are presented, including long-term results of a personal series of 106 patients with cancer of the uterine...
Primary invasive ocular squamous cell carcinoma in a horse. A 12-year-old Haflinger gelding was presented to the veterinary medical teaching hospital of the University of Zurich with a light-pink raised mass on the temporal limbus and conjunctiva of the left eye. Squamous cell carcinoma was confirmed histologically after keratectomy and cryotherapy. Seven months later, a smooth pink, progressively enlarging mass was observed within the cornea of the left eye. Ultrasonographically, the mass was not only infiltrating the corneal stroma but seemed to protrude into the anterior chamber. The globe was surgically removed and submitted for pathology. A histol...
Expression of cell cycle associated proteins cyclin A, CDK-2, p27kip1 and p53 in equine sarcoids. Equine sarcoids are benign fibroblastic skin tumours affecting equids worldwide. Whilst the pathogenesis is not entirely understood, infection with Bovine Papillomavirus (BPV) types 1 and 2 has been implicated as a major factor in the disease process, however the mechanism by which BPV infection contributes to sarcoid pathology is not clear. In this study, we show that the majority of sarcoids express the BPV-1 major transforming gene E6. Further, we demonstrate that sarcoid lesions are not associated with high levels of cellular proliferation as assessed by Ki67 expression or with expression ...
In vivo evaluation of an EIAV vector for the systemic genetic delivery of therapeutic antibodies. Lentiviral-based vectors hold great promise as gene delivery vehicles for the treatment of a wide variety of diseases. We have previously reported the development of a nonprimate lentiviral vector system based on the equine infectious anaemia virus (EIAV), which is able to efficiently transduce dividing and nondividing cells both in vitro and in vivo. Here, we report on the application of EIAV vectors for the systemic delivery of an antibody fusion protein designed for the treatment of cancer. The therapeutic potential of a single chain antibody against the tumour-associated antigen, 5T4, fuse...
Splenic haemangiosarcoma with metastasis to the cervical musculature in an aged pony. An aged pony gelding presented with sudden onset of neck pain, depression and ataxia and weakness of the hindlegs, together with longer-term weight loss. Diagnostic procedures failed to isolate the cause of these signs and, despite symptomatic treatment, the animal's condition deteriorated until it required euthanasia. Unassigned: Post mortem examination revealed the presence of multiple splenic and hepatic haemangiosarcomata, with metastases to the lung and dorsal cervical muscles overlying C1 and C2 vertebrae. No lesions were present in the spinal cord, spinal column or brain. Conclusions: T...
Tail-base mass from a “horse of a different color”. A 14-year-old bay Thoroughbred gelding was presented for evaluation of a mass at the base of the tail. The mass had been present for 1 year, and recently had begun to increase in size. Additional masses were found around the eye and shoulder. A fine-needle aspirate of the tail-base mass revealed highly anaplastic round to polyhedral cells containing dark green to black cytoplasmic granules interpreted to be melanin. Histologically, the mass was composed of pleomorphic, poorly pigmented, round to polyhedral cells interpreted to be neoplastic melanocytes. With immunohistochemistry, the cells wer...
Metastatic tumors to the adrenal glands in domestic animals. Although metastases to the adrenals are common in humans, they have not been thoroughly studied in animals. The purpose of this retrospective study was to document the types of malignant tumors that metastasize to canine, feline, equine, and bovine adrenals, and the rate at which they do so. The average rate of adrenal involvement in metastatic cancer was 112/534 (21.0%) in dogs, 12/81 (14.8%) in cats, 18/67 (26.9%) in horses, and 5/16 (31.3%) in cattle. In dogs, 26 different tumor types metastasized to the adrenals. Pulmonary, mammary, prostatic, gastric, and pancreatic carcinomas, and melano...
Effects of treatment with and without adjuvant radiation therapy on recurrence of ocular and adnexal squamous cell carcinoma in horses: 157 cases (1985-2002). To determine the effects of treatment with and without adjuvant radiation therapy on recurrence of ocular and adnexal squamous cell carcinoma (SCC) at specific anatomic locations in horses. Methods: Retrospective study. Methods: 91 horses. Methods: Medical records of horses with histologically confirmed ocular and adnexal SCC evaluated from 1985 to 2002 were reviewed. Sex, breed, age, type of treatment, location, and recurrence of SCC were recorded. Two treatment groups determined by recurrence of SCCs treated with and without adjuvant radiation therapy were established. Results: The anatomic ...
Comparative histopathology of grey-horse-melanoma and human malignant melanoma. Equine melanoma shows striking features particularly with regard to clinical development in grey horses: in contrast to malignant melanoma in humans and in solid coloured horses that are characterized by early onset of metastasis, pigment cell tumours display almost benign clinical features in ageing grey horses. Through evolution, grey horses appear to be in a favourable position in regard to the biological behaviour of melanomas. Yet unknown factors inhibiting or retarding early melanoma metastasis may be responsible for this phenomenon. In this study, immunostaining profiles and histopathol...
Pigmented squamous cell carcinoma of the conjunctiva of a horse. Abstract A heavily pigmented tumor was removed from the lateral, perilimbal, bulbar conjunctiva of a bay Thoroughbred horse. Excision was incomplete and the base of the tumor was lasered on the assumption that the tumor was a melanoma. No other ophthalmic lesions were seen. Histology showed the mass to be a pigmented squamous cell carcinoma (SCC). The prognosis and recommended treatment protocols are different for SCC and melanoma. This is, to the best of our knowledge, the first report of an ocular, pigmented SCC in the veterinary literature.
Application of the comet assay for investigation of oxidative DNA damage in equine peripheral blood mononuclear cells. Oxidative stress occurs when antioxidant defense mechanisms are overwhelmed by free radicals and may lead to DNA damage, which has been implicated in processes such as aging and diseases such as cancer. The two main techniques presently used to quantify DNA damage are measurement of 8-hydroxydeoxyguanosine and the Comet assay (also known as single-cell gel electrophoresis). The aim of this study was to apply the comet assay to equine peripheral blood mononuclear cells (PBMCs) and identify two conditions in which we hypothesized that oxidative DNA damage would be increased in PBMCs: aging and e...
Excision as treatment of dermal melanomatosis in horses: 11 cases (1994-2000). To determine whether excision was an acceptable treatment for dermal melanomatosis in horses. Methods: Retrospective study. Methods: 11 horses with dermal melanomatosis involving the perineal, perianal, or perirectal region or ventral surface of the tail in which treatment consisted of tumor excision. Methods: Medical records were reviewed. Follow-up information was obtained from owners through telephone interviews. Results: 9 of the 11 horses were alive at the time of follow-up interviews. None of the horses had regrowth at the surgery site where the primary tumor was removed. There were no c...
Ultrasound-guided biopsy as a diagnostic aid in three horses with a cranial mediastinal lymphosarcoma. An ultrasound examination of the thorax of three horses which were performing poorly or had mild signs of colic showed that they had a cranial mediastinal mass and a pleural effusion. A cytological examination of the pleural fluid showed that it did not contain neoplastic cells. A histological examination of an ultrasound-guided core biopsy of the cranial mediastinal mass showed that in each of the three horses it was a lymphosarcoma.
Use of chemotherapy for treatment of a mixed-cell thoracic lymphoma in a horse. A 4-year-old Oldenburg mare was evaluated because of signs of lower airway disease and subsequently developed bilateral pleural effusion. Neoplastic cells were not identified in the fluid sample obtained via the initial thoracocentesis. A thoracic mass was detected radiographically, but its location prevented collection of a tissue sample. A diagnosis of lymphoma was made on the basis of results of immunophenotyping of pleural fluid specimens. Treatment of thoracic lymphoma in horses has been attempted, but there are limited data regarding chemotherapeutic-induced remission. In this horse, rem...
