Immunohistochemical Detection of COX-2 in Feline and Canine Actinic Keratoses and Cutaneous Squamous Cell Carcinoma

Immunohistochemical Expression Levels of Epidermal Growth Factor Receptor, Cyclooxygenase-2, and Ki-67 in Canine Cutaneous Squamous Cell Carcinomas

Squamous cell carcinoma (SCC) stands as the second most prevalent skin cancer in dogs, primarily attributed to UV radiation exposure. Affected areas typically include regions with sparse hair and pale or depigmented skin. The significance of spontaneous canine cutaneous SCC as a model for its human counterpart is underscored by its resemblance. This study assesses the expression of key markers-Epidermal Growth Factor Receptor (EGFR), Cyclooxygenase-2 (Cox-2), and Ki-67-in canine cutaneous SCC. Our objective is to investigate the association between their expression levels and classical clinicopathological parameters, unraveling the intricate relationships among these molecular markers. In our retrospective analysis of 37 cases, EGFR overexpression manifested in 43.2% of cases, while Cox-2 exhibited overexpression in 97.3%. The EGFR, Cox-2 overexpression, and Ki-67 proliferation indices, estimated through immunohistochemistry, displayed a significant association with the histological grade, but only EGFR labeling is associated with the presence of lymphovascular emboli. The Ki-67 labeling index expression exhibited an association with EGFR and Cox-2. These findings propose that EGFR, Cox-2, and Ki-67 hold promise as valuable markers in canine SCC. EGFR, Cox-2, and Ki-67 may serve as indicators of disease progression, offering insights into the malignancy of a lesion. The implications extend to the potential therapeutic targeting of EGFR and Cox-2 in managing canine SCC. Further exploration of these insights is warranted due to their translational relevance and the development of targeted interventions in the context of canine SCC.

Pan-tumour analysis of COX-2 expression in dogs

Cyclooxgenase-2 (COX-2) is associated with inflammatory microenvironment and tumour progression. COX-2 expression was reported in canine tumours, and anti-COX treatment showed therapeutic effects in selected tumour types. Currently, direct comparisons between different tumour types or reports were impossible due to varying evaluation protocols. Additionally, COX-2 expression in relatively uncommon tumours were yet to be evaluated. Here, we analysed COX-2 expression across various tumour types in dogs in a consistent protocol, aiming to revisit accumulated evidence in the field and report novel candidate tumours for anti-COX therapy. COX-2 expression in 32 histological types of tumours, which consisted of 347 samples in total, was investigated using immunohistochemistry followed by the Belshaw's method scoring (range: 0-12). More than the half of the samples expressed COX-2 in mast cell tumours, transitional cell carcinoma in the urinary tract, squamous cell carcinoma, liposarcoma, and melanoma, with COX-2 median scores ranging from 1-8. On the other hand, <20% tissues expressed COX-2 in the half of tumour types investigated. Overall COX-2 positive rate was 27%. In conclusion, the results confirmed COX-2 expression in the well-known COX-2-expresing tumour types and suggested novel candidate tumours for anti-COX-2 therapy. At the same time, overall COX-2 expression was low, and inter- and intra-histology heterogeneity was apparent. This study will provide a foundation reference for future research in canine tumours.

Effects of selective cyclooxygenase-2 inhibitor robenacoxib on primary cells derived from feline injection-site sarcoma

Feline injection-site sarcomas (FISSs) are highly invasive malignant mesenchymal neoplasms that arise from injection sites in cats. Although the tumorigenesis of FISSs is still uncertain, there is a consensus that FISS is associated with chronic inflammation caused by irritation of injection-related trauma and foreign chemical substances. Chronic inflammation can provide a proper microenvironment for tumour development, which has been known as one of the risk factors of tumorigenesis in many tumours. To investigate the tumorigenesis of FISS and screen for its potential therapeutic targets, cyclooxygenase-2 (COX-2), an inflammation-enhancing enzyme, was selected as a target for this study. In vitro experiments using FISS- and normal tissue-derived primary cells and robenacoxib, a highly selective COX-2 inhibitor, were performed. The results demonstrated that expression of COX-2 could be detected in formalin-fixed and paraffin-embedded FISS tissues and FISS-derived primary cells. Cell viability, migration and colony formation of FISS-derived primary cells were inhibited, and cell apoptosis was enhanced by robenacoxib in a dose-dependent manner. However, susceptibility to robenacoxib varied in different lines of FISS primary cells and was not completely correlated with COX-2 expression. Our results suggest that COX-2 inhibitors could be potential adjuvant therapeutics against FISSs.

Frontal sinus carcinoma in forty-one dogs (2001-2022)

Reports on canine frontal sinus carcinomas (FSCs) are scarce. This retrospective review of 41 dogs with FSC (2001-2022) describes demographic and clinical characteristics of canine FSC and reports the clinical experience and overall survival following treatment with toceranib phosphate (TOC) and meloxicam in 10 cases. Median age at diagnosis was 10.6 years (range: 6.5-15.4 years). There was a male-to-female-ratio of 2.4:1. The most common breeds were Jack Russell Terriers (JRT) (n = 7; 17.1%) and Rottweilers (n = 3, 7.3%). Mesocephalic breeds (70.6%) were most commonly affected, brachycephalics accounted for 8.8%. The most frequent clinical signs included skull deformation dorsomedial to the eye (87.5%), pain/head-shyness (40.0%), ocular (22.5%)/nasal (17.5%) discharge, and exophthalmos (17.5%). Duration of symptoms prior to diagnosis varied from a few days to 9 months. There were no neurological signs at initial presentation despite imaging evidence of osteolysis of the lamina interna of the frontal bone in most dogs (69.4%). In 11.5%, pulmonary changes suggestive of metastasis or concurrent primary pulmonary neoplasia were present. Tumour types included squamous cell carcinoma (58.5%), unspecified carcinoma (29.3%), and adenocarcinoma (9.8%). Ten dogs were treated with TOC (median 2.8 mg/kg EOD or three times per week) and meloxicam (0.1 mg/kg, EOD) (TOC-M), resulting in subjective regression of skull deformity in 8/10 (80.0%) patients. Overall median survival time with TOC-M was 183.5 days (range: 120-434 days). FSCs typically present with skull deformation, but no overt neurological signs. Male dogs and JRT may be overrepresented. The use of TOC-M in FSC appears promising and warrants further prospective evaluation.

Canine squamous cell carcinoma: Electrochemotherapy association with surgery and correlation with overall survival

Squamous cell carcinoma (SCC) is an important malignancy in dogs, due to its incidence and clinical presentation, which can be of locally aggressive single or multiple lesions with a metastatic potential. The objective of this investigation was to evaluate SCC response to treatment, anatomopathological and immunohistochemical characteristics, disease-free interval and overall survival time. 54 dogs with histopathologically diagnosed SCC were included in this study. Their mean age was 9.16 years with a range of 1-14 years. Of the 54 animals in the study, 34 (65.4%) had white skin and white fur coats. There was a significant correlation between fur coat colour and the development of tumours in areas of sun exposure (p = .001). Animals with tumours in areas of the body exposed to the sun had longer overall survival time than animals with tumours in areas not associated with sun exposure (p = .001). Surgery combined with electrochemotherapy (ECT) yielded a survival rate 32% higher than using a surgical approach alone (HR = 0.32, p = .038, IC = 0.11-0.94). ECT, with or without surgery, had an objective response rate of 90.9%. Local lymph node and/or distant site metastasis at diagnosis, or at some point during follow-up, occurred in 34.6% (18/52) of animals. Animals with tumours in sun exposed locations had more aggressive histopathological characteristics but had longer overall survival time. This is probably due to individualised therapeutic treatment with both surgery and ECT.

Evaluation of cyclooxygenase-2 fluctuation via a near-infrared fluorescent probe in idiopathic pulmonary fibrosis cell and mice models

Idiopathic pulmonary fibrosis (IPF) is a devastating and fatal interstitial lung disease due to various challenges in diagnosis and treatment. Due to its complicated pathogenesis and difficulty in early diagnosis, there is no effective cure. Cyclooxygenase-2 (COX-2) is inextricably associated with pulmonary fibrosis. The abnormal level of COX-2 leads to extremely exacerbated pulmonary fibrosis. Therefore, we reported a near-infrared fluorescent probe Cy-COX to detect the fluctuation of COX-2 levels during pulmonary fibrosis and explain its important protective effect. The probe Cy-COX showed a significant enhancement of fluorescence signal to COX-2 with excellent selectivity and sensitivity. In order to clarify the relationship between COX-2 and pulmonary fibrosis, we used the probe Cy-COX to detect COX-2 fluctuation in organisms with pulmonary fibrosis. The results showed that the COX-2 level increased in the early stage and decreased in the late stage with the aggravation of pulmonary fibrosis. Furthermore, up-regulation of COX-2 levels can effectively alleviate the severity of pulmonary fibrosis. Therefore, Cy-COX is a fast and convenient imaging tool with great potential to predict the early stage of pulmonary fibrosis and evaluate the therapeutic effects.

Squamous cell carcinoma of the anal sac in two cats

This report describes two cases of feline anal sac squamous cell carcinoma. Cat 1 was managed with a multimodal approach combining surgical resection, radiation therapy and systemic therapy (toceranib phosphate; Palladia™) until local recurrence was identified at 236 days postsurgery. At that time, the cat received carboplatin. With the tumour being progressive, the cat was euthanased 552 days post initial surgery. Cat 2 was managed palliatively with a non-steroidal anti-inflammatory (meloxicam) and supportive medications. Unfortunately, with further decline in quality of life following initial diagnosis, the cat was euthanased 28 days later. Squamous cell carcinoma should be considered as a possible differential diagnosis when a cat is presented for investigation of an anal sac mass.

Gene expression of prostaglandin EP4 receptor in three canine carcinomas

BACKGROUND

Chronic inflammation mediated by the cyclooxygenase enzymes, specifically their product prostaglandin E2 (PGE2), can result in the development of cancer. PGE2 promotes cell proliferation, apoptosis, and angiogenesis through interaction with its specific receptors (EP1 receptor - EP4 receptor [EP1R-EP4R]). In multiple human cancers, the expression of EP4R is associated with the development of malignancy and a poor prognosis. The expression of EP4R has not yet been evaluated in canine tumors. The aim of this study was to characterize the mRNA gene expression of EP4R (ptger4) in canine squamous cell carcinoma (SCC), apocrine gland anal sac adenocarcinoma (AGASACA), and transitional cell carcinoma (TCC). Archived tumor samples of canine cutaneous SCC (n = 9), AGASACA (n = 9), and TCC (n = 9), and matched archived normal tissue controls were evaluated for mRNA expression of canine EP4R using RNA in situ hybridization (RNAscope®). Quantification of RNAscope® signals in tissue sections was completed with an advanced digital pathology image analysis system (HALO). Data was expressed as copy number, H-index, and percent tumor cell expression of EP4R.

RESULTS

In all canine SCC, AGASACA, and TCC samples evaluated, strong universal positive expression of EP4R was identified. For SCC and AGASACA, mRNA EP4R expression was statistically higher than that of their respective normal tissues. The TCC tissues displayed significantly less mRNA EP4R expression when compared to normal bladder mucosa.

CONCLUSIONS

These results confirm the mRNA expression of canine EP4R in all tumor types evaluated, with SCC and AGASACA displaying the highest expression, and TCC displaying the lowest expression. This study also represents the first reported veterinary evaluation of EP4R expression using the novel in situ hybridization technique, RNAscope®.

Cyclooxygenase-2 as a Biomarker with Diagnostic, Therapeutic, Prognostic, and Predictive Relevance in Small Animal Oncology

In canine and feline populations, the number of neoplasm cases continues to increase around the world. Attempts are being made in centres of research to identify new biomarkers that speed up and improve the quality of oncological diagnostics and therapy in human and animal tumour patients. Cyclooxygenase-2 (COX-2) is a promising biomarker with increasing relevance to human oncology, but as yet with less application in veterinary oncology. The expression of COX-2 increases significantly during pathological processes involving inflammation, pain or fever. It is also overexpressed in humans presenting various types of tumours and in selected types of tumours in animals, particularly in dogs. This article discusses the expression of COX-2 in canine and feline tumours, the importance of COX-2 as a biomarker with diagnostic, therapeutic, prognostic and predictive relevance in oncology, and the clinical significance of inhibiting COX-2 overexpression in tumours.

Avian Papilloma and Squamous Cell Carcinoma: a Histopathological, Immunohistochemical and Virological study

In this retrospective study, we describe the histopathological findings in seven papillomas and 45 squamous cell carcinomas (SCCs) from psittacine birds, raptors and domestic fowl. The age of affected birds ranged from 3 to 40 years, with median age significantly higher in psittacines (P = 0.014). The majority of tumours were located in the skin (24/52, 46.2%) or uropygial gland (10/52, 19.2%). Thirty of the SCCs (66.7%) were well differentiated and 15 (33.3%) were poorly-differentiated. SCCs exhibited a significantly higher degree of nuclear pleomorphism (P = 0.005) and a greater proportion were ulcerated (P = 0.001) compared with papillomas; however, there was no significant difference in mitotic count (MC) or inflammation score. The expression of cyclo-oxygenase (COX)-2 and E-cadherin was investigated by immunohistochemistry. The COX-2 total score (TS) was significantly higher in SCCs compared with papillomas (P = 0.002), but the difference between COX-2 TS of well- and poorly-differentiated SCCs was not significant. COX-2 labelling was predominantly cytoplasmic, but some tumours had concurrent membranous and/or perinuclear labelling. SCCs with membranous labelling had a significantly higher MC (P = 0.028). A significantly higher proportion of SCCs were negative for E-cadherin compared with papillomas (P = 0.042), but there was no significant difference between well- and poorly-differentiated SCCs. Fourteen papillomas and SCCs from psittacines were also tested by polymerase chain reaction for the presence of Psittacus erithacus papillomavirus 1 and Psittacid herpesvirus 1, but all samples tested negative. We demonstrate for the first time the expression of COX-2 and E-cadherin in avian tissues, and suggest that these markers may be useful in differentiating papillomas from SCCs, particularly when sample size is small.

Periovulatory administration of firocoxib did not alter ovulation rates and mitigated post-breeding inflammatory response in mares

Non-steroidal anti-inflammatory drugs (NSAIDs) are a therapeutic option for the treatment of inflammation. However, negative effects of non-selective NSAIDs for treatment of mares with endometritis have been described, including delayed uterine clearance and impairment of ovulations. Firocoxib is a specific cyclooxygenase-2 (COX-2) inhibitor and has the ability to act in the uterus of mares. We investigated the effects of firocoxib on ovulation rate, numbers of polymorphonuclear neutrophils (PMNs), and COX-2 protein levels in the endometrial tissue of susceptible mares after insemination. Two experiments were conducted. In experiment 1, twenty mares were evaluated in two consecutive estrous cycles broken into the following groups: Control - no pharmacological interference; Treatment - mares were treated with 0.2 mg/kg of firocoxib orally. The treatment began on the day of ovulation induction, and firocoxib was administered until one day after artificial insemination (AI). Ovulation was induced with 1 mg of deslorelin acetate and the mares were inseminated 24 h after the injection. Ovulation was confirmed 48 h after induction, and embryos were collected eight days after ovulation. Experiment 2: Nine mares susceptible to persistent mating-induced endometritis (PMIE) were artificially inseminated. The mares were examined with ultrasound and inseminated with fresh semen in two consecutive cycles, control and treated, in a cross-over study design. The amount of intrauterine fluid was measured, and endometrial samples were collected 24 h after AI. The number of PMNs was determined by endometrial cytology and biopsy, and COX-2 labeling in endometrial samples was evaluated by immunohistochemistry. Firocoxib treatment did not induce ovulatory failure or affect embryo recovery rate in Experiment 1. In Experiment 2, firocoxib treatment reduced inflammation after AI in mares as evidenced with results regarding PMN numbers/percentage and endometrial COX-2 staining. In conclusion, the proposed treatment with firocoxib reduced endometrial inflammation in mares susceptible to PMIE after breeding, with no adverse effects.

Clinical features and outcome of dermal squamous cell carcinoma in 193 dogs (1987-2017)

Squamous cell carcinoma (SCC) is a frequently recognized dermal tumour in dogs and has been described as a common pathology induced by solar ultraviolet radiation exposure. Little has been published about this neoplasm with regard to clinical features and outcome in dogs. This retrospective study included 193 dogs from a single institution histopathologically diagnosed with SCC of the dermis. Thirty-eight percent of all dogs had documented histopathologic actinic change. The overall median survival time was 1004 days, with the population demonstrating actinic change associated with a significantly longer survival time (median 1359 days, range 16-3530 days) compared to dogs without actinic change (median 680 days, range 16-3066 days) and this achieved significance on multivariate analysis (hazard ratio 0.42, 95% confidence interval 0.193-0.930, P = 0.032). These data demonstrate increased survival of dogs with SCC demonstrating actinic change over those with non-actinic SCCs, and purports long-term survival for these animals. Dogs received a variety of treatment approaches as a retrospective study, and future prospective studies will be necessary to investigate whether adjunct therapies such as radiation or chemotherapy offer improvement in survival for dermal SCC in the dog.

Prognostic factors for cats with squamous cell carcinoma of the nasal planum following high-dose rate brachytherapy

OBJECTIVES

The aim of the study was to investigate retrospectively the prognostic impact of variables such as sex, neuter status, breed, age, number of lesions, location and size of the tumour, tumour extension beyond the nasal planum, ulceration and lymph node status, among others, in a population of cats treated with high-dose rate brachytherapy.

METHODS

This study reviews the outcome of 58 cats with cytologically and/or histologically confirmed squamous cell carcinoma of the nasal planum, treated at the Clinic Alliance (Bordeaux, France) with high-dose rate brachytherapy from 2010-2016. The total radiation dose delivered was 30 Gy, administered in two different schedules: five fractions of 6 Gy for a period of 4 days (Tuesday-Friday) or four fractions of 7.5 Gy for a period of 3 days (Tuesday- Thursday). Data were collected from cats' clinical records.

RESULTS

Complete response was achieved in 72% (n = 36) of the cats, partial response in 24% (n = 13) and 2% (n = 1) did not respond. Median progression-free survival and overall survival times were 316 and 835 days, respectively.

CONCLUSIONS AND RELEVANCE

Results indicated that sex (P = 0.045), extension of the tumour from the nasal planum to the upper lip (P = 0.015), tumour size (P = 0.015; P = 0.001), the existence of a previous treatment (P = 0.043) and the tumour response to high-dose rate brachytherapy (P = 0.038; P <0.001) are prognostic factors for cats with squamous cell carcinoma of the nasal planum following high-dose rate brachytherapy.

Association between Degree of Anaplasia and Degree of Inflammation with the Expression of COX-2 in Feline Injection Site Sarcomas

Feline injection site sarcomas (FISSs) are mesenchymal neoplasms that develop at the sites of delivery of vaccines or other injectable products. Vaccine adjuvants can trigger an intense and persistent inflammatory response that may lead to neoplastic transformation. The proinflammatory role of cyclo-oxygenase (COX)-2 is well known and its overexpression has prognostic value in multiple neoplastic processes. One hundred and seventeen FISSs were evaluated for the degree of inflammation and anaplasia. Immunohistochemistry was used to determine the expression of COX-2 in these sarcomas. There was a significant association between the degree of inflammation and the expression of COX-2 by neoplastic cells. COX-2 expression was lower in tumours with higher degrees of anaplasia. These findings may be useful in predicting the sensitivity of FISSs to treatment with COX-2 inhibitors. The potential therapeutic use of such agents could then be restricted to tumours with lower degrees of anaplasia.

Investigation of immune cell markers in feline oral squamous cell carcinoma

Squamous cell carcinoma is the most common oral cancer in the cat and presents as a locally aggressive lesion for which an effective therapeutic protocol remains elusive. Feline oral squamous cell carcinoma (OSCC) shares many clinical characteristics with human head and neck squamous cell carcinoma (HNSCC). Accordingly, present studies were conducted to determine similarities for immune markers shared by feline OSCC and human HNSCC. Biopsies harvested from a feline patient cohort-1 (n = 12) were analyzed for lymphoid cell infiltrates by immunohistochemistry (IHC). Results revealed unique patterns of T cell infiltration involving both neoplastic epithelium and stroma that were detected in most patient tumor biopsies (92%) examined by IHC staining for CD3. Intratumoral B cell infiltrates were detected within tumor stroma only, based on IHC staining for CD79a and CD20 for all patients within the same cohort-1. Infiltration of tumors by a regulatory CD4 T cell subset (Tregs) defined by expression of the forkhead transcription factor FoxP3, was also detected in biopsies from 57% of patients and involved infiltration of neoplastic epithelium and stroma. Patient biopsies were also examined for expression of immunomodulator cyclooxygenase (COX)-2 and revealed positive but weak staining of neoplastic epithelium in a significant proportion of cases (75%). Interestingly, COX-2 expression was detected in both neoplastic epithelium and stroma. Blood collected from a second cohort of feline OSCC patients (n = 9) revealed an increased frequency of circulating CD4+FoxP3+ T cells when compared to healthy adult controls (n = 7) (P = 0.045), although frequencies of CD4+CD25+FoxP3+ T cells were comparable between patients and healthy pet cat controls. Lastly, biopsies from feline OSCC patients were characterized for histologic subtype using a classification scheme previously described for human HNSCC. This analysis revealed the conventional subtype as the predominant variant (75%) with conventional subtypes split evenly between well differentiated and moderately differentiated carcinomas. Two cases were classified as papillary and one case as basaloid subtypes. Correlations between subtype, immune marker scores or circulating Treg frequencies and clinical characteristics or outcome were not detected, most likely due to small patient numbers within patient cohorts. However, findings from these studies provide a preliminary step in the characterization of immune and histologic markers that will be critical to defining prognostic immune markers for feline OSCC and potential targets for testing of immunotherapeutics also relevant to human HNSCC in future studies.

Cyclooxygenase-2 immunoexpression in intestinal epithelium and lamina propria of cats with inflammatory bowel disease and low grade alimentary lymphoma

Background

Cyclooxygenase 2 (COX-2) is an inducible isoform by cellular activation, proinflammatory cytokines and growth factors. The aims of the current study were to evaluate COX-2 immunoexpression in epithelial and lamina propria (LP) of cats with inflammatory bowel disease (IBD) and low grade alimentary lymphoma (LGAL), as well as to correlate them with clinical signs and histopathological scoring. Cats diagnosed with IBD and LGAL (2007–2013) were included in the current study. Feline chronic enteropathy activity index (FCEAI) was calculated for all cases. Control group was composed by 3 healthy indoor cats and 5 sick cats died or were euthanized (non-gastrointestinal illness). Diagnosis and classification of IBD and LGAL was established according to the WSAVA gastrointestinal standardization group template and the National Cancer Institute formulation, respectively. Furthermore, a modified WSAVA template was applied for LGAL evaluation. Immunolabelling for COX-2 (polyclonal rabbit anti-murine antibody) was performed on biopsy samples. Epithelial and LP (inflammatory or neoplastic cells) COX-2 immunolabelling was calculated according to the grade and intensity. The most representative segment scored by the WSAVA and the modified WSAVA were used for statistical analysis.

Results

Significant difference was found regarding COX-2 intensity overexpression in the epithelial cells of IBD and LGAL groups when compared to control cats, but not between the groups of sick cats, whereas no differences were found regarding the grade of immunoreactivity between groups. No difference was found for COX-2 immunoexpression at the LP between all groups. However, 3 cats from LGAL group showed COX-2 expression in neoplastic cells at the LP. There were no correlations between epithelial or LP COX-2 expression and FCEAI and histological alterations.

Conclusions

Increased COX-2 intensity at the epithelial cells observed in cats with IBD and LGAL may be secondary to the inflammatory response or a protective function in the intestinal reparation. COX-2 expression at the LP was presented in 33% of LGAL. This result provides a reason for further investigation concerning the role of COX-2 expression in feline alimentary lymphoma.

Uterine clinical findings, fertility rate, leucocyte migration, and COX-2 protein levels in the endometrial tissue of susceptible mares treated with platelet-rich plasma before and after AI

Persistent mating-induced endometritis (PMIE) results in decreased fertility in horses, thereby causing a significant impact in the horse market. Platelet-rich plasma (PRP), a modulator of the inflammatory response, has been largely used in veterinary medicine. Here, we investigated the effects of PRP on uterine inflammation, conception rate, endometrial polymorphonuclear neutrophil (PMN) migration, and COX-2 protein levels in the endometrial tissue. Thirteen PMIE-susceptible mares were used for artificial insemination (AI). The mares were inseminated with fresh semen in three consecutive cycles in a cross-over study design. The following cycle classifications were used: control cycle, no pharmacological interference; pre-AI, 20 mL of PRP was infused 24 h before AI; and post-AI, 20 mL of PRP was infused four h after AI. Follicular dynamics were monitored daily by transrectal ultrasound. When a follicle larger than 35 mm was detected, ovulation was induced with deslorelin acetate (1 mg, im). AI was performed 24 h after ovulation induction. Intrauterine fluid (FLU) was evaluated by ultrasonography before and 24 h after AI. PMNs in uterine cytology (CYT) and biopsy (HIS) were also observed before and 24 h after AI. Pregnancy was determined within 14 days after ovulation. Number of COX-2 positive cells was evaluated by immunohistochemistry. Both PRP treatments resulted in a decrease of PMNs in the CYT after breeding when compared to controls. FLU did not differ between cycles; however, the conception rates were significantly higher in the PRP mares. Mares positive for endometritis decreased in both treatment groups, and a more intense positive COX-2 labeling was observed in the control group when compared to the two treatment groups. In conclusion, PRP beneficially reduces inflammatory response in PMIE mares independent of when treatments were administered, thus increasing chances of successful pregnancy.

Correlation Between Cyclo-oxygenase-2 and Vascular Endothelial Growth Factor Expression in Canine and Feline Squamous Cell Carcinomas

Overexpression of cyclo-oxygenase (COX)-2 is involved in tumour growth and spread by modulating the production of angiogenic factors such as vascular endothelial growth factor (VEGF). Expression of COX-2 and VEGF was investigated immunohistochemically in 51 canine and feline cutaneous and non-cutaneous squamous cell carcinomas (SCCs) and the correlation between expression of these molecules and clinicopathological variables was evaluated. COX-2 and VEGF expression was not observed in normal skin keratinocytes. COX-2 overexpression occurred in 53% and 61% of the canine and feline SCCs, respectively. The expression of both markers was higher in cutaneous compared with non-cutaneous SCCs. In both species COX-2 and VEGF expression was correlated with the progression of the disease, but not with the presence of lymphatic invasion, tumour grading or tumour classification in the cutaneous tumours. Further study will be required to understand the role of the COX-2 pathway in angiogenesis in SCC.

Growth Factors and COX2 Expression in Canine Perivascular Wall Tumors

Canine perivascular wall tumors (PWTs) are a group of subcutaneous soft tissue sarcomas developing from vascular mural cells. Mural cells are involved in angiogenesis through a complex crosstalk with endothelial cells mediated by several growth factors and their receptors. The evaluation of their expression may have relevance since they may represent a therapeutic target in the control of canine PWTs. The expression of vascular endothelial growth factor (VEGF) and receptors VEGFR-I/II, basic fibroblast growth factor (bFGF) and receptor Flg, platelet-derived growth factor B (PDGFB) and receptor PDGFRβ, transforming growth factor β1 (TGFβ1) and receptors TGFβR-I/II, and cyclooxygenase 2 (COX2) was evaluated on frozen sections of 40 PWTs by immunohistochemistry and semiquantitatively scored to identify their potential role in PWT development. Statistical analysis was performed to analyze possible correlations between Ki67 labeling index and the expression of each molecule. Proteins of the VEGF-, PDGFB-, and bFGF-mediated pathways were highly expressed in 27 (67.5%), 30 (75%), and 19 (47.5%) of 40 PWTs, respectively. Proteins of the TGFβ1- and COX2-mediated pathways were highly expressed in 4 (10%) and 14 (35%) of 40 cases. Statistical analysis identified an association between VEGF and VEGFR-I/II (P = .015 and .003, respectively), bFGF and Flg (P = .038), bFGF and PDGFRβ (P = .003), and between TGFβ1 and COX2 (P = .006). These findings were consistent with the mechanisms that have been reported to play a role in angiogenesis and in tumor development. No association with Ki67 labeling index was found. VEGF-, PDGFB-, and bFGF-mediated pathways seem to have a key role in PWT development and growth. Blockade of tyrosine kinase receptors after surgery could represent a promising therapy with the aim to reduce the PWT relapse rate and prolong the time to relapse.

Expression of cyclo-oxygenases-1 and -2, and microsomal prostaglandin E synthase-1 in penile and preputial papillomas and squamous cell carcinomas in the horse

REASONS FOR PERFORMING STUDY

Penile and preputial papilloma and squamous cell carcinoma (SCC) are commonly diagnosed in horses. Papillomas have the potential to progress to potentially lethal SCC. Knowledge of pathogenetic mechanisms may help in prevention and definition of treatment targets.

STUDY DESIGN

Retrospective study using archived material.

OBJECTIVES

To determine the expression of cyclo-oxygenase 1 (COX-1), cyclo-oxygenase 2 (COX-2) and microsomal prostaglandin E synthase-1 (mPGES-1) in penile and preputial normal tissue, papilloma and SCC in horses, and whether expression of these enzymes is influenced by degree of inflammation and differentiation grade.

METHODS

Tumour differentiation grade, degree of inflammation and COX-1, COX-2 and mPGES-1 expression in 75 formalin-fixed paraffin embedded samples of penile and preputial papilloma and SCC of 68 horses were investigated by histopathology and immunohistochemistry.

RESULTS

Inflammation was more prominent in SCC compared with papilloma. No correlation between expression of COX-1 or COX-2 and inflammation was found. Expression of mPGES-1 was weakly correlated with inflammation. Expression of COX-1, COX-2 and mPGES-1 was found in 42.6%, 50.7% and 96.0% of lesions respectively, but less than 1% of cells were immunopositive for COX-1 and COX-2 in 59.4% and 84.2% of cases respectively. Expression of COX-1 was moderately negatively correlated with differentiation grade, COX-2 was not correlated and mPGES-1 was poorly negatively correlated.

CONCLUSIONS

Expression of COX-1 and COX-2 in penile and preputial SCC in the horse is poor and COX inhibitors may thus be of little value for prevention or treatment. Microsomal PGES-1 is more prominently expressed in well-differentiated tissue compared with poorly differentiated tissue. Further research on the role of mPGES-1 in carcinogenesis is needed to assess its potential use as a treatment target. Knowledge of arachidonic pathway enzyme expression and their role in equine penile and preputial carcinogenesis may help in developing preventive and therapeutic strategies.

Influence of seminal plasma on leucocyte migration and amount of COX-2 protein in the jenny endometrium after insemination with frozen-thawed semen

After mating, seminal plasma has an immuno-modulatory effect on the endometrium in some mammals. In jennies, achieving conception via artificial insemination (AI) with frozen-thawed semen is generally much more difficult than in mares. The endometrial inflammatory response is hypothesized to be a contributing factor to the lesser fertility. Following a cross-over experimental design, the uterine inflammatory response of six jennies was evaluated at 6h after AI with frozen-thawed semen (deposited in the uterine body) in the presence or absence of autologous seminal plasma (+SP or -SP). The endometrial cytology and histology of the animals were examined by uterine lavage, uterine swabbing and biopsy. The amount of cyclooxygenase-2 (COX-2) protein in endometrial cells was also evaluated. As a control (C), the same examinations were made before any AI procedure (i.e., when the jennies were in oestrus). Large numbers of polymorphonuclear neutrophils (PMN) were observed in the -SP and +SP cytology and biopsy samples; more than in the C samples. The -SP samples also had intense COX-2 labelling; less labelling was detected in the +SP and C samples (no significant difference between these latter two types). Thus, while the presence of SP does not change the post-AI number of PMNs with regard to that detected in its absence, it does reduce COX-2 protein. Further research into the complex mix of molecules in SP and its effects during AI might help increase the pregnancy rates achieved in jennies.

Cutaneous Squamous Cell Carcinoma in the Cat

Practical relevance:

Squamous cell carcinoma (SCC) is a tumour that commonly involves the skin or oral cavity and is, therefore, an important differential diagnosis for any cutaneous lesion(s), especially any non-healing scabbing lesions on the eyelids, nasal planum or ears of light-coloured cats.

Clinical challenges:

Superficial lesions of the nasal planum, discrete small eyelid lesions and lesions on the tips of pinnae are relatively easily treated, but higher stage lesions are more challenging to manage and may compromise the cosmetic appearance of the cat.

Audience:

This review article is aimed at all veterinary practitioners that see cats.

Evidence base:

The review summarises the peer-reviewed literature relating to our understanding of feline cutaneous SCC. Unfortunately, the literature is limited and in need of updating in areas.

Effect of ketoprofen treatment on the uterine inflammatory response after AI of jennies with frozen semen

Artificial insemination (AI) involving the placing of frozen-thawed semen directly into the jenny uterine body is associated with very low pregnancy rates. This might be because of an exacerbation of the acute response of the endometrium to sperm, as seen in mares with persistent induced mating endometritis. Pregnancy rates can be increased in such mares, however, by including anti-inflammatory treatments in the insemination protocol (Bucca S, Carli A, Buckley T, Dolci G, Fogarty U. The use of dexamethasone administered to mares at breeding time in the modulation of persistent mating induced endometritis. Theriogenology 2008;70:1093-100; Rojer H, Aurich C. Treatment of persistent mating-induced endometritis in mares with the non-steroid anti-inflammatory drug vedaprofen. Reprod Domest Anim 2010;45:e458-60). To investigate the endometritis caused by the use of frozen-thawed semen in jennies, and to assess the response to ketoprofen treatment, endometrial cytological samples and biopsies from six healthy jennies were examined in a crossover design experiment. Samples were taken from jennies in estrus (E; control) and at 6 hours after AI with or without ketoprofen (+K and -K, respectively). Ketoprofen was administered iv 24 hours before and for 4 days after insemination (total = 2.2 mg/kg/24 hours for 5 days). All animals showed a severe inflammatory response to semen deposition. Polymorphonuclear neutrophil numbers in the cytological smears and biopsies differed significantly between the +K and E animals. No significant differences were recorded, however, between the +K and -K treatments. Eosinophils were observed in all sample types from all groups; these cells appear to be a feature of the normal jenny endometrium. Slight fibrosis was observed in some biopsies, but no significant relationship with inflammation was found. Intense cyclooxygenase-2 (COX-2) immunohistochemical labeling was detected in the -K biopsies. Less intense labeling was seen in those of the +K animals, and mainly localized in the stratum compactum. No differences in COX-2 labeling were observed between the +K and E animals. Plasma concentrations of ketoprofen remained detectable until 2 hours after administration, after which the compound was rapidly eliminated. In summary, jennies are susceptible to endometritis after insemination with frozen-thawed semen. Ketoprofen reduces this inflammation by inhibiting COX-2; no reduction in the number of polymorphonuclear neutrophils occurs. The physiological and pharmacological characteristics of jennies should be taken into account when designing treatments for acute endometritis aimed at enhancing pregnancy rates after insemination with frozen-thawed sperm.