T. J. Scase

COX-1 and COX-2 Expression in Feline Oral Squamous Cell Carcinoma

This study demonstrated immunohistochemically the expression of cyclooxygenase-1 (COX-1) and cyclooxygenase-2 (COX-2) in feline oral squamous cell carcinoma (FOSCC), with primary polyclonal antibodies raised against human epitopes. COX-2 immunolabelling was intracytoplasmic and, in some neoplastic cells, perinuclear; it was demonstrated in a small proportion (< or = 1%) of neoplastic cells and its intensity was usually mild to moderate. In contrast, all neoplastic tissues showed extensive nuclear and cytoplasmic COX-1 immunolabelling. Cytoplasmic COX-1 immunolabelling was less intense than nuclear labelling in neoplastic tissue. In the adjacent histologically normal oral mucosa, COX-2 immunolabelling was absent. The cytoplasmic and nuclear intensity and distribution of COX-1 immunolabelling was significantly higher in neoplastic tissue than in adjacent normal oral mucosa. The results indicate that COX-1 and COX-2 are overexpressed in FOSCC, but the clinical and pathophysiological significance of this finding remains to be determined.

Association of Ki67 index with prognosis for intermediate-grade canine cutaneous mast cell tumours.

Intermediate-grade mast cell tumours (MCT) represent a heterogeneous population of tumours. The prognosis for the majority of dogs is excellent following surgical excision, but a minority die because of their disease. A previous study identified Ki67 expression as a predictor of prognosis in all three grades of MCT. The purpose of this study was to validate those results in a new group of dogs, with intermediate-grade MCT only. Ki67 immunohistochemistry was performed on intermediate-grade MCT from 163 dogs with known outcome. Digital microscopy images were taken from each tumour, and an index calculated of Ki67-positive cells. Ki67 index as a binary variable with a cut-off value of 1.8% was confirmed to be associated with prognosis (hazard ratio = 19.1, P < 0.0001) for this cohort of dogs. The 1-year, 2-year and 3-year survival probabilities (with standard errors) of 127 dogs with a Ki67 index <or=1.8% were [0.95 (0.024), similar for all] and for 36 dogs with a Ki67 index >1.8% were 0.54 (0.100), 0.45 (0.101) and 0.33 (0.104), respectively.

Immunohistochemical detection of HER‐2/neu expression in spontaneous feline mammary tumours

Mammary gland tumours (MGT) are the third most common tumours in the cat. At least 85% are malignant and metastasis is common. The HER-2/neu protooncogene encodes a 185-kDa transmembrane tyrosine receptor kinase protein. Approximately 25-30% of human MGT demonstrate HER-2/neu protein overexpression in the malignant cells, and overexpression has been associated with an increased metastatic propensity and a decreased prognosis. No reports have been published, to date, investigating the expression of Her-2/neu in cats or cats with spontaneous mammary tumours. Based on the increased percentage of malignant mammary cancers in cats, compared to that in dogs, and the correlation of an increased malignancy and a decreased prognosis with Her-2 overexpression in human mammary cancer, we hypothesized that cats with spontaneous malignant mammary adenocarcinoma overexpress Her-2/neu in the neoplastic mammary epithelial cells. Thirty cats with MGT were assayed for Her-2/neu immunohistochemical expression. The median percentage of cells from feline MGT expressing Her-2/neu by utilizing the Dako polyclonal and CB11 monoclonal antibodies was 85 and 92.5, respectively. Her-2/neu expression intensity grades 2 and 3 consistent with the overexpression by utilizing the Dako polyclonal and CB11 monoclonal antibodies were observed in 90 and 76.7% of cats with MGT, respectively. The level of overexpression concordance across the two antibodies was 70%. The results from this study suggest that Her-2/neu overexpression is common in cats with spontaneous MGT, and therefore appears to represent an excellent model for Her-2/neu-overexpressing human breast cancer.

Breed, gender and neutering status of British dogs with anal sac gland carcinoma

This study details the breed, gender and neutering status of a large cohort of British canine patients suffering from histologically confirmed anal sac gland carcinoma. Estimates of the relative risk for the development of this disease attributable to these factors are calculated. To reduce the impact of sampling errors, cases were selected from veterinary histopathology laboratories rather than referral hospital databases, and multiple estimates of the general British canine population were used. The weaknesses of the statistical assumptions made are discussed. There was no evidence to support a gender predisposition for the development of this condition. English cocker spaniels are significantly over-represented, with a mean relative risk estimate of 7.3. The mean relative risk estimate associated with being neutered was 1.4; the effect of neutering appeared to be more significant in male dogs compared with that in female dogs.

Histopathologic, immunohistochemical, and cytologic analysis of feline myeloma-related disorders: further evidence for primary extramedullary development in the cat.

Feline myeloma-related disorders (MRD) are rare neoplasms of plasma cells. The multistep transformation model of myeloma in humans is based on the premise that plasma cells undergo neoplastic transformation primarily within the intramedullary compartment and that over time they become poorly differentiated and metastasize to extramedullary locations. Historically, diagnostic criteria used for human multiple myeloma have been applied to the cat, with the assumption that feline MRD commonly arises in the intramedullary compartment. Our objectives were to describe the features of feline MRD confirmed by cytology, histopathology, histochemistry, and immunohistochemistry and to categorize these tumors. A priori hypotheses were 1) tumor category predicts survival and 2) cats with well-differentiated tumors commonly have extramedullary involvement in contrast to human myeloma patients. This multicenter, retrospective study identified 26 MRD cases. There was good agreement between histopathologic and cytologic tumor categorization. Histochemistry and immunohistochemistry were shown to be valuable adjunct tests in the diagnosis of MRD. Cats with well-differentiated tumors had increased median survival relative to those with poorly differentiated tumors (254 versus 14 days). We have reported that marked extramedullary involvement at initial clinical presentation is significantly more common in the cat than in human MRD patients. In this study, we demonstrate that cats with well-differentiated tumors more commonly have extramedullary involvement than human myeloma patients with well-differentiated tumors (90% versus 20%, P < 0.0002). These results contrast strongly with the human myeloma model of primary intramedullary neoplastic transformation and suggest that primary extramedullary neoplastic transformation may be more common in feline MRD.

Myeloma-related disorders in cats commonly present as extramedullary neoplasms in contrast to myeloma in human patients: 24 cases with clinical follow-up

Background:Myeloma‐related disorders (MRD) are rare neoplasms of plasma cells. Published case reports describe a diversity of clinical presentations with confusing terminology and diagnostic criteria as a consequence of the assumption that MRD in cats are analogous to those in dogs or humans. Objective: The aim of the study was to describe clinical, clinicopathologic and imaging findings, response to treatment, survival and possible associations with other diseases or vaccination in a large case series. A priori hypotheses were that cats with MRD commonly present with extramedullary involvement and uncommonly have radiographic bone lesions, in contrast to human patients. Animals:Twenty‐four cats with MRD confirmed by cytology or histopathology and immunohistochemistry. Method: A multicenter retrospective study was performed. Results:Two types of clinical presentation were observed. The first group (n = 17) had neoplasia involving abdominal organs, bone marrow, or both. All developed systemic clinical signs and paraproteinemia. Five of 7 cats that received chemotherapy improved clinically or had decreased serum globulin concentration (median survival, 12.3 months; range, 8.5–22 months). The second group comprised 7 cats with skin masses, 2 of which were paraproteinemic and developed rapidly worsening systemic signs. In cats without systemic signs, excision of the skin masses appeared to be associated with prolonged survival (up to 2.4 years). Cats with MRD commonly presented with extramedullary involvement (67%), versus humans with MRD (5%) (P < .001), and uncommonly presented with radiographic bone lesions (8%) versus humans with MRD (80%) (P < .001). Conclusions: Radiographic bone lesions are uncommon in cats with MRD and extramedullary presentation is common, relative to human myeloma.

Characterization of spindle cell component of ferret (Mustela putorius furo) adrenal cortical neoplasms – correlation to clinical parameters and prognosis

Adrenal cortical epithelial tumours are common in ferrets. A variant tumour type with prominent spindle cell proliferation has been identified. We characterized these variant tumours with light microscopy and immunohistochemical analysis and correlate these features to clinical parameters and prognosis. We classified 24 ferret adrenal cortical masses with recognizable spindle cell proliferation obtained from the AMC and AFIP databases, based on percentage of spindle cells present and features of malignancy. These masses were separated into hyperplastic nodules and adenomas (both with 1-24% spindle cells), mixed adenomas (>or=25% spindle cells), adenocarcinomas (1-24%) and mixed adenocarcinomas (>or=25% spindle cells). Tumours were evaluated immunohistochemically for smooth muscle actin (SMA) and estrogen receptor (ER) expression. Disease-free interval (DFI) and survival time (ST) were calculated using Kaplan-Meier product limit method. Of 24 cases of spindle cell variant adrenal tumours, one was a hyperplastic nodule, 10 were adenomas, three were mixed adenomas, six were adenocarcinomas and four were mixed adenocarcinomas. The proliferative spindle cell cytoplasm was SMA-positive (smooth muscle myocyte origin). ER positivity, seen in nine of 24 cases, was restricted to adenocarcinomas, mixed adenomas and mixed adenocarcinomas. DFI and ST were significantly reduced in mixed adenocarcinomas or tumours with ER expression. DFI was significantly reduced in tumours with marked smooth muscle. The spindle cell component of these variant adrenal tumours is smooth muscle in origin. The presence of abundant smooth muscle, a more malignant histologic grade (mixed adenocarcinomas) and ER expression are significantly positively correlated to both decreased DFI and decreased ST.

Vascular endothelial growth factor (VEGF) and VEGF receptor expression in biopsy samples of liver from dogs with congenital portosystemic shunts.

Surgical attenuation of a congenital portosystemic shunt (CPSS) results in increased liver mass, development of intrahepatic portal vasculature and improved liver function. Vascular endothelial growth factor (VEGF) is a key regulator of angiogenesis. The aim of this study was to investigate the role of VEGF and its receptor in the hepatic response to CPSS surgery. The study included 99 dogs with CPSS treated with either partial or complete suture attenuation. Forty-four dogs with partial attenuation underwent a second surgery for complete attenuation. The expression of VEGF and VEGF receptor 2 (VEGFR2) in biopsy samples of liver was assessed by immunohistochemistry with rabbit anti-human VEGF polyclonal antibody and mouse anti-human VEGFR2 monoclonal antibody. Expression of these molecules was graded. The proportion of samples expressing VEGF was significantly greater in samples from dogs with CPSS compared with control samples (P=0.04) and the proportion of samples expressing VEGFR2 was significantly greater in control samples compared with samples from dogs with CPSS (P=0.04). VEGF labelling grade decreased significantly (P=0.038) and VEGFR2 increased significantly (P=0.046) between first and second surgery. The decrease in VEGF may reflect transient expression, preferential expression of other factors, reperfusion of existing vessels and/or increased angiogenesis before surgery in the form of arterialization and subsequent reduction due to improved portal blood flow. Partial suture attenuation was associated with a degree of normalization of VEGF and VEGFR2 expression when compared with the control samples. Further investigation is needed to provide more information on the hepatic response to CPSS surgery.

Expression of E-cadherin in canine anal sac gland carcinoma and its association with survival.

The objective of this study was to determine whether an association could be demonstrated between survival and the expression of the adhesion molecule E-cadherin by the neoplastic cells in a group of dogs with anal sac gland carcinomas (ASGCs). Archived formalin-fixed, paraffin wax-embedded primary tumour specimens were obtained for 36 cases of canine ASGC with known clinical management and survival data. Immunohistochemical methods were used to evaluate E-cadherin expression by the neoplastic cells and data were evaluated for an association between E-cadherin expression and survival. On univariate analysis, the median survival time for cases with tumours expressing E-cadherin in more than 75% of cells was significantly greater than that for cases with tumours expressing E-cadherin in fewer than 75% of cells (1168 versus 448 days, P = 0.0246). Both E-cadherin expression and presence or absence of distant metastases were significantly associated with survival on multivariate analysis. This study demonstrates that expression of E-cadherin at the cytoplasmic membrane in canine ASGCs is variable and potentially predictive of survival.

Unilateral squamous cell carcinoma of the renal pelvis with hydronephrosis in a cat

A 4-year-old female neutered domestic shorthair cat was presented for evaluation of gradual onset of lethargy and anorexia. Physical examination revealed moderate abdominal distension. Investigations performed included complete blood count, serum biochemistry, urinalysis, pyelocentesis, abdominal fluid analysis, abdominal ultrasonography and exploratory celiotomy. Nephrectomy was performed on the hydronephrotic kidney and a sample of the omentum was also taken, as it was grossly abnormal. No other abnormalities were found in the remainder of the abdominal organs. Findings were consistent with unilateral hydronephrosis and squamous cell carcinoma of the renal pelvis with abdominal carcinomatosis. The patient was given supportive treatment while the results of the biopsies from the renal tissue and the omentum were pending. The patient deteriorated a short time after surgical intervention and was euthanased. This is the first report of a squamous cell carcinoma arising from the renal pelvis in a cat. A comparison with the disease presentation in humans is also discussed.