Review of the comparative pathological and immunohistochemical features of human and canine cutaneous melanocytic neoplasms

Melanocytic neoplasms originate from melanocytes and melanoma, the malignant form, is a common canine neoplasm and the most aggressive human skin cancer. Despite many similarities between these neoplasms in both species, only a limited number of studies have approached these entities in a comparative manner. Therefore, this review compares benign and malignant melanocytic neoplasms in dogs and humans, exclusively those arising in the haired skin, with regard to their clinicopathological, immunohistochemical and molecular aspects. Shared features include spontaneous occurrence, macroscopic features and microscopic findings when comparing human skin melanoma in the advanced/invasive stage and canine cutaneous melanoma, immunohistochemical markers and several histopathological prognostic factors. Differences include the apparent absence of active mutations in the BRAF gene in canine cutaneous melanoma and less aggressive clinical behaviour in dogs than in humans. Further studies are required to elucidate the aetiology and genetic development pathways of canine cutaneous melanocytic neoplasms. Evaluation of the applicability of histopathological prognostic parameters commonly used in humans for dogs are also needed. The similarities between the species and the recent findings regarding genetic mutations in canine cutaneous melanomas suggest the potential utility of dogs as a natural model for human melanomas that are not related to ultraviolet radiation.

Intratesticular transplantation of allogenic mesenchymal stem cells mitigates testicular destruction after induced heat stress in Miniature-horse stallions

Testicular degeneration (TD) is the most frequent cause of sub or infertility in stallions. Currently, mesenchymal stem cells (MSC) have been studied as a therapeutic option for several diseases including induced-TD in laboratory animals. Therefore, this study aimed to evaluate the effect of intratesticular MSC therapy on the testicular histology of stallions submitted to scrotal heat stress. Ten healthy Miniature-horse stallions were submitted to testicular heat stress induced by a heating wrap device (42-45°C). Afterward, the stallions were divided into two groups and treated seven days later. MSCs-treated stallions were treated with an intratesticular injection of 10 × 106 of MSCs diluted in 5 mL of PBS, whereas placebo-treated stallions had 5 mL of PBS intratesticular injected. All stallions had testicular biopsies collected seven days before and one- and 14-days post-heat stress and were castrated 30 days after testicular insult. Tissue sections were stained with H&E and evaluated for the tubular and luminal diameter, epithelial thickness, seminiferous tubules (STs) integrity, the number of spermatozoa in the STs, and the percent of abnormal STs. Significance was set at P≤0.05. In both groups, testicular heat stress damaged the STs (P<0.05). However, STs' parameters were improved in MSCs-treated stallions compared to placebo-treated stallions 30 days after the testicular insult (P<0.05). In conclusion, the results of the present study suggest that intratesticular MSC therapy provided a therapeutic advantage in rescuing acute TD in stallions. However, further studies are essential to evaluate the benefits of this therapy on semen parameters and stallions with idiopathic TD.

Histological, Immunohistochemical, Biomechanical, and Wettability Evaluations of the Leukocyte- and Platelet-Rich Fibrin Membranes Derived from Canine Blood

This study aimed to perform histological, immunohistochemical, biomechanical, and wettability assessments of leukocyte- and platelet-rich fibrin (L-PRF) membranes obtained from the blood of healthy dogs. Ten client-owned Labrador Retriever dogs were enrolled. Blood samples were obtained from the external jugular vein using a vacuum tube without anticoagulant, which was immediately centrifuged at 400g for 12 min in a dedicated centrifuge. The L-PRF clot was removed from the tube, and the red clot was released from the buffy coat using a spatula. The membrane was produced using a PRF box. Histological examination identified the three portions of the L-PRF membranes. The first portion was composed mainly of red blood cells with the presence of a low number of leukocytes among them. The second portion was composed of white blood cells, mainly neutrophils. The third portion was composed of the fibrin network which was characterized by acidophilic staining. The immunohistochemical analysis showed that vascular endothelial growth factor and platelet-derived growth factor were expressed in all samples at different intensities, both in cellular components and fibrin mesh. The tensile test and wettability assessments were measured in membranes 30 min and 3 h after production. The 30 min L-PRF membranes supported twice the ultimate tensile strength compared to 3 h L-PRF membranes. The wettability of the 30 min sample membranes was statistically higher than the 3 h sample membranes. In conclusion, the centrifugation protocol allowed production of the L-PRF membrane using canine blood and this was confirmed by histological and immunohistochemical analysis. The mechanical resistance and wettability of the L-PRF membrane were significantly reduced over time.

Simultaneous occurrence of inflammatory bowel disease and trichomonosis in a Maine coon cat

A 2-year-old, 4.2 kg, spayed female, Maine coon cat was referred to the veterinary hospital for evaluation of hyporexia, slow growth, and chronic, intermittent, mucoid, bloody, voluminous, and fetid diarrhea. The diarrhea had been observed since the cat was acquired from a cattery at 4 months of age; with acute worsening in the 5 d before presentation. Abdominal palpation revealed moderate pain. Ultrasonographic examination showed thickening of the jejunal wall and ileal loops, increased echogenicity of the jejunal mucosa, and enlargement of the jejunal and ileocolic lymph nodes. Histopathology of full-thickness intestinal biopsies showed moderate, diffuse, lymphoplasmacytic, erosive enteritis with hemorrhage and edema. Diffuse, lymphoplasmacytic, erosive colitis with mild, interstitial fibrosis and hemorrhage was also noted. The ileocecal lymph node biopsy showed eosinophilic lymphadenitis. Based on the immunohistochemical evaluation of intestinal samples with CD3 and CD79a antibodies, a diagnosis of lymphoma was ruled out. Fecal polymerase chain reaction testing was positive for Tritrichomonas foetus. Based on these results, inflammatory bowel disease and trichomonosis were diagnosed. Treatment for the cat included a hypoallergenic diet and an oral omega-3 fatty acid supplement, in conjunction with prednisolone, to manage the inflammatory bowel disease. Ronidazole was administered to target the Tritrichomonas foetus. The cat was clinically normal during a follow-up examination after 6 months of treatment.

In Vivo Models to Evaluate Antitumor Drugs Effect on Vasculogenic Mimicry

The vasculogenic mimicry (VM) in vivo evaluation is challenging, and new models have been proposed to evaluate antitumor effect of different compounds using in vivo models. However, there is no gold standard in vivo models established for VM evaluation. As occurs for other in vivo tumor analysis, the use of immunodeficient mouse model and cell line with in vivo tumorigenicity and ability to induce vasculogenic mimicry is the most used model.

Primary Uterine Hemangiosarcoma in a Thoroughbred: A Case Report

A 1.8-year-old maiden Thoroughbred filly, without previous history of mating or reproductive management, was referred for clinical inspection due to the presence of sanguineous vaginal discharge and severe abdominal pain. Transrectal palpation indicated uterine asymmetry, and transrectal ultrasonography revealed a mass near the cervix measuring 8.3 cm in diameter, with heterogeneous echogenicity, a trabeculated center, and a well-defined hyperechoic border. Smaller masses surrounded the larger uterine mass. During the examination, the mare expelled a uterine mass through the vulva. Histological and immunohistochemical (CD31 and Factor VIII) examinations of the expelled mass suggested a diagnosis of hemangiosarcoma. Therefore, a therapeutic hysterectomy was performed, and examinations of the uterine tissue confirmed the diagnosis. However, the mare was euthanized 2 weeks later due to postoperative complications. The animal was subjected to necropsy, and intestinal adhesions in the surgical incision were diagnosed as postoperative complications. No other neoplasms were found during necropsy, establishing the primary origin of the tumor. This case study presents the first known report of uterine hemangiosarcoma in an equine species.

Masquelet-Induced Membrane Characteristics in Chicken Radii Bone Defects

This study evaluated the formation of a Masquelet-induced membrane created through the formation of segmental bone defects in the radii of 15 healthy domestic chickens. When the chickens were in a surgical plane of anesthesia, a 1.5-cm segmental bone defect was produced in the left radius, which was subsequently filled with a bone cement spacer during its pasty polymerization phase. The bone defects were evaluated through radiographic imaging immediately after surgery and at 7, 15, 21, and 30 days after the creation of the bone defect. Five birds were euthanatized at 15, 21, and 30 days postoperatively for histological evaluation of the bone defect site. Immediate postoperative radiographic examination of the radii showed the presence of bone cement, which occupied the segmental bone defect. Thirty days after the surgical procedure, the presence of new bone formation at the fractured extremities was evident in the 5 remaining chickens. Histologically, the induced-membrane had 3 distinct zones at 15 days postoperatively, including 1 cell layer in contact with the bone cement spacer, 1 layer with collagen fibers, and 1 layer in contact with muscle, which was composed of disorganized connective tissue, active fibroblasts, and blood vessels. Twenty-one days after surgery, the zones were less defined, and there were metaplastic areas comprising cartilage and bone. Postoperative, diffuse mineralization of the membrane was observed 30 days after the surgical procedure. Formation of the induced membrane was observed during all periods of evaluation. The best histological characteristics for the Masquelet-induced membrane were detected 15 days after the formation of the bone defect, suggesting this would be the optimal time for second-stage surgery for bone reconstruction.

Structural and Ultrastructural Morphological Evaluation of Giant Anteater (Myrmecophaga tridactyla) Prostate Gland

Simple Summary

The giant anteater (Myrmecophaga tridactyla) is a vulnerable species that lives in South America, extinct in several countries. In the past year, different governmental and non-governmental programs were created for the giant anteater’s conservation. However, little is known regarding the reproductive aspects of this species. Thus, to the best of our knowledge, this is the first description of a morphological and ultrastructural analysis of the prostate gland.

Abstract

The giant anteater (Myrmecophaga tridactyla) is a vulnerable species from Central and South America, and is considered possibly extinct in Belize, Guatemala, El Salvador, and Uruguay. Due to the species’ conservation and reproductive importance, this research aimed to characterize the morphology, histochemical, immunohistochemical, and ultrastructural feature of the giant anteater prostate gland. For this, we collected 11 giant anteater prostate glands and performed macroscopic, morphological, histochemical, immunohistochemical, and ultrastructural analysis. Nine prostate glands from an adult subject and two from young subjects were studied. Grossly, the adult giant anteater prostate gland is divided in two distinct zones; the central zones (composed mainly of ducts) and the peripheral zones (of acini formed by secretory cells). The secretory cells showed positive periodic acid–Schiff staining. Furthermore, the immunohistochemical characterization revealed a similar human prostate pattern, with p63 staining basal cells, uroplakin III (UPIII) superficial cells of prostatic urethra, androgen receptor (AR) expressing nucleus of secretory and stromal cells, and prostatic specific antigen (PSA) staining prostatic epithelial cells. Overall, our research provided an in-depth morphological description of the giant anteater’s prostate gland, providing valuable information for futures studies focused on giant anteater conservation.

Proteomics Approach of Rapamycin Anti-Tumoral Effect on Primary and Metastatic Canine Mammary Tumor Cells In Vitro

Rapamycin is an antifungal drug with antitumor activity and acts inhibiting the mTOR complex. Due to drug antitumor potential, the aim of this study was to evaluate its effect on a preclinical model of primary mammary gland tumors and their metastases from female dogs. Four cell lines from our cell bank, two from primary canine mammary tumors (UNESP-CM1, UNESP-CM60) and two metastases (UNESP-MM1, and UNESP-MM4) were cultured in vitro and investigated for rapamycin IC₅₀. Then, cell lines were treated with rapamycin IC₅₀ dose and mRNA and protein were extracted in treated and non-treated cells to perform AKT, mTOR, PTEN and 4EBP1 gene expression and global proteomics by mass spectrometry. MTT assay demonstrated rapamycin IC₅₀ dose for all different tumor cells between 2 and 10 μM. RT-qPCR from cultured cells, control versus treated group and primary tumor cells versus metastatic tumor cells, did not shown statistical differences. In proteomics were found 273 proteins in all groups, and after data normalization 49 and 92 proteins were used for statistical analysis for comparisons between control versus rapamycin treatment groups, and metastasis versus primary tumor versus metastasis rapamycin versus primary tumor rapamycin, respectively. Considering the two statistical analysis, four proteins, phosphoglycerate mutase, malate dehydrogenase, l-lactate dehydrogenase and nucleolin were found in decreased abundance in the rapamycin group and they are related with cellular metabolic processes and enhanced tumor malignant behavior. Two proteins, dihydrolipoamide dehydrogenase and superoxide dismutase, also related with metabolic processes, were found in higher abundance in rapamycin group and are associated with apoptosis. The results suggested that rapamycin was able to inhibit cell growth of mammary gland tumor and metastatic tumors cells in vitro, however, concentrations needed to reach the IC₅₀ were higher when compared to other studies.

Transcriptome of Two Canine Prostate Cancer Cells Treated With Toceranib Phosphate Reveals Distinct Antitumor Profiles Associated With the PDGFR Pathway

Canine prostate cancer (PC) presents a poor antitumor response, usually late diagnosis and prognosis. Toceranib phosphate (TP) is a nonspecific inhibitor of receptor tyrosine kinases (RTKs), including vascular endothelial growth factor receptor (VEGFR), platelet-derived growth factor receptor (PDGFR), and c-KIT. This study aimed to evaluate VEGFR2, PDGFR-β, and c-KIT protein expression in two established canine PC cell lines (PC1 and PC2) and the transcriptome profile of the cells after treatment with TP. Immunofluorescence (IF) analysis revealed VEGFR2 and PDGFR-β protein expression and the absence of c-KIT protein expression in both cell lines. After TP treatment, only the viability of PC1 cells decreased in a dose-dependent manner. Transcriptome and enrichment analyses of treated PC1 cells revealed 181 upregulated genes, which were related to decreased angiogenesis and cell proliferation. In addition, we found upregulated PDGFR-A, PDGFR-β, and PDGF-D expression in PC1 cells, and the upregulation of PDGFR-β was also observed in treated PC1 cells by qPCR. PC2 cells had fewer protein-protein interactions (PPIs), with 18 upregulated and 22 downregulated genes; the upregulated genes were involved in the regulation of parallel pathways and mechanisms related to proliferation, which could be associated with the resistance observed after treatment. The canine PC1 cell line but not the PC2 cell line showed decreased viability after treatment with TP, although both cell lines expressed PDGFR and VEGFR receptors. Further studies could explain the mechanism of resistance in PC2 cells and provide a basis for personalized treatment for dogs with PC.

Comparison of two different doses of bleomycin in electrochemotherapy protocols for feline cutaneous squamous cell carcinoma nonsegregated from ultraviolet light exposure

Cutaneous squamous cell carcinoma (cSCC) is one of the most common skin tumors in cats due to chronic exposure to ultraviolet light. Local treatments such as electrochemotherapy (ECT) promote disease control or even complete remission. We hypothesize that cats could benefit from treatments using bleomycin at reduced dosages. A prospective nonrandomized single-blind study evaluated the clinical parameters, site lesion, staging, disease-free interval (DFI) and survival time by comparing the standard dose of bleomycin (15,000 UI/m2) (n = 22) with a reduced dose (10,000 UI/m2) (n = 34) in cats with cSCC that underwent ECT as the sole treatment modality. No statistically significant difference in DFI or overall survival was observed between the 2 groups. A higher DFI was found in cats with a small tumor size (less than 0.33 cm3) compared with that for cats with a large tumor size (P = 0.045). Furthermore, a reduced overall survival time for cats with a higher stage in the standard group SG (T3 and T4) (P = 0.004) was observed when compared to that for cats with a lower stage (T1 and T2). In conclusion, ECT using both doses of bleomycin may achieve the same response rate in terms of the overall response, DFI, and overall survival.

Inflammatory Breast Cancer: Clinical Implications of Genomic Alterations and Mutational Profiling

Simple Summary

Inflammatory breast cancer (IBC) is an aggressive disease with high mortality rates. Nowadays, there is no targeted treatment for this tumor type. Based on this context, we investigated the molecular profile of this disease by using well-established methodologies (high-resolution microarray platform, targeted next-generation sequencing, and immunohistochemistry) that have proven potential to unveil cancer biomarkers. We found alterations related to IBC aggressiveness and metastasis (gains of MDM4, losses of CHL1, and high homologous recombination deficiency scores), and worse overall survival (variants in HR and mismatch repair genes). We also compared the mutational profiling of our cases with literature data, which includes both non-IBC and IBC cases, validating our findings. Overall, we describe genetic alterations with the potential to be used as prognostic or predictive biomarkers and ultimately improve IBC patients’ care.

Abstract

Inflammatory breast cancer (IBC) is a rare and aggressive type of breast cancer whose molecular basis is poorly understood. We performed a comprehensive molecular analysis of 24 IBC biopsies naïve of treatment, using a high-resolution microarray platform and targeted next-generation sequencing (105 cancer-related genes). The genes more frequently affected by gains were MYC (75%) and MDM4 (71%), while frequent losses encompassed TP53 (71%) and RB1 (58%). Increased MYC and MDM4 protein expression levels were detected in 18 cases. These genes have been related to IBC aggressiveness, and MDM4 is a potential therapeutic target in IBC. Functional enrichment analysis revealed genes associated with inflammatory regulation and immune response. High homologous recombination (HR) deficiency scores were detected in triple-negative and metastatic IBC cases. A high telomeric allelic imbalance score was found in patients having worse overall survival (OS). The mutational profiling was compared with non-IBC (TCGA, n = 250) and IBC (n = 118) from four datasets, validating our findings. Higher frequency of TP53 and BRCA2 variants were detected compared to non-IBC, while PIKC3A showed similar frequency. Variants in mismatch repair and HR genes were associated with worse OS. Our study provided a framework for improved diagnosis and therapeutic alternatives for this aggressive tumor type.

Histopathological Terminology Standards for the Reporting of Prostatic Epithelial Lesions in Dogs

The terminology applied to canine prostatic epithelial lesions, especially carcinomas, is currently not standardized and this hampers the ability of pathologists to study the biological and clinical significance of these lesions. The aim of this review is to present the essential histomorphological diagnostic attributes of a wide spectrum of prostatic epithelial lesions in dogs. In addition to the traditionally recognized prostatic hyperplasia, hormonal atrophy, prostatitis, squamous metaplasia, adenocarcinoma and transitional cell (urothelial) carcinoma, new entities are described and discussed in order to provide veterinary pathologists with a basic atlas of common histological lesions of the canine prostate that is comprehensive and easy to use.

Association between decreased expression of estrogen receptor alpha, androgen receptor and phosphatase and tensin homolog immunoexpression in the canine prostate

ABSTRACT: Canine prostate gland is a hormonal dependent organ and its imbalance of estrogen and androgen receptor expressions are directly associated with the development of different diseases. Due to the lack of information regarding the behavior of the aforementioned receptors in canine prostate cancer (PC), this study aimed to identify estrogen receptor alpha (ERα), androgen receptor (AR), Ki67 and phosphatase and tensin homolog (PTEN) protein expressions in canine PC by immunohistochemistry. We found nuclear expression of ERα and AR in the epithelial cells of normal canine samples and a loss of protein expression in PC samples. Normal samples showed Ki67 expression in a few basal cells and the PC samples showed the highest mean of positive cells (253.1). Canine prostate cancer showed a high proliferative index, which was associated with independence of hormonal actuation. PTEN showed positive nuclear and cytoplasmic expression in normal canine samples and a loss in PC. Loss of ERα, AR and PTEN indicated that canine PC exhibits the same immunohistochemical phenotype as in human patients with PC resistant to hormonal therapy. Therefore, canine PC should be considered as a model to study human PC resistant to hormonal therapy.

p-mTOR, p-4EBP-1 and eIF4E expression in canine prostatic carcinoma

The mTOR/4E-BP1/eIF4E pathway plays important roles in the neoplastic transformation process and in tumour growth. In men, the mTOR/4E-BP1/eIF4E pathway was described as altered in different tumours, including prostate cancer (PC). Apart from humans, the dog is the only species that develops PC with high frequency and is considered a good model for comparative oncology initiatives. Due to limited information on this pathway in canine tumours, this study aimed to investigate mTOR, 4E-BP1 and eIF4E gene and protein expression in canine PC, as well as in metastatic and normal prostatic tissues, and to evaluate the correlations between gene/protein expression and Gleason score (GS) in PC. A total of 35 formalin-fixed paraffin-embedded (FFPE) samples, including 13 of normal prostatic tissue, 17 PC samples and 5 metastasis samples, were evaluated by immunohistochemistry and qPCR. mTOR gene mutation in the kinase domain was also investigated. We identified higher p-mTOR and eIF4E protein levels in canine PC with higher GS values (≥ 8) and a significant positive correlation in expression between these proteins. eIF4E overexpression was observed in metastasis relative to expression in normal samples. Our data suggest that p-mTOR and eIF4E expression is positively correlated with GS in canine PC, similar to the pattern in humans. More studies of the mTOR/4EBP1/eIF4E pathway should be performed to identify possible correlations of the proteins involved with clinical and pathologic findings in canine PC and the roles of these proteins as therapeutic targets for the treatment of canine PC.

Deregulation of E-cadherin, β-catenin, APC and Caveolin-1 expression occurs in canine prostate cancer and metastatic processes

Prostate cancer is a heterogeneous disease with high levels of clinical and gene heterogeneity, consequently offering several targets for therapy. Dogs with naturally occurring prostate cancer are useful models for molecular investigations and studying new treatment efficacy. Three genes and proteins associated with the WNT pathway (β-catenin, APC and E-cadherin) and Caveolin-1 (CAV-1) were evaluated in canine pre-neoplastic proliferative inflammatory atrophy (PIA), prostate cancer and metastatic disease. The APC gene methylation status was also investigated. As in human prostate cancer, cytoplasmic and nuclear β-catenin, which are fundamental for activating the canonical WNT pathway, were found in canine prostate cancer and metastasis. Membranous E-cadherin was also lost in these lesions, allowing cellular migration to the stroma and nuclear localization of β-catenin. In contrast to human prostate tumours, no APC downregulation or hypermethylation was found in canine prostate cancer. The CAV-1 gene and protein overexpression were found in canine prostate cancer, and as in humans, the highest levels were found in Gleason scores ≥8. In conclusion, as with human prostate cancer, β-catenin and E-cadherin in the WNT pathway, as well as Caveolin-1, are molecular drivers in canine prostate cancer. These findings provide additional evidence that dogs are useful models for studying new therapeutic targets in prostate cancer.

Pilot assessment of vascular endothelial growth factor receptors and trafficking pathways in recurrent and metastatic canine subcutaneous mast cell tumours

Canine subcutaneous mast cell tumour (scMCT) shows less aggressive biological behaviour than cutaneous MCT. Vascular endothelial growth factor receptor 2 (VEGFR2) is expressed by neoplastic cells in canine scMCT, but the relevance of this signalling pathway for disease pathobiology is not clear. The objective of this study was to quantify VEGF‐A, VEGFR2, pVEGFR2, the VEGF co‐receptor Neuropilin 1 (NRP‐1) and the E3 ubiquitin protein ligase c‐Cbl in canine scMCT, and to evaluate their association with disease outcome. Immunohistochemical staining for biomarkers was quantified from 14 cases of canine scMCT using manual and computer‐assisted methods. Kaplan–Meier curves were generated for disease‐free survival (DFS) and compared using Mantel–Cox log‐rank analysis. Cases with high levels of neoplastic cell VEGFR2, pVEGFR2 or c‐CBL immunoreactivity had significantly reduced DFS. All cases displayed neoplastic cells positive for VEGF‐A, which was significantly associated with pVEGFR2 immunoreactivity. There were also significant positive correlations between VEGFR2 and pVEGFR2, and between c‐CBL and pVEGFR2 levels. This pilot study demonstrates the potential utility of these markers in a subset of scMCT in dogs.

Overexpression of Ephrin A3 Receptor in Canine Prostatic Carcinoma

Ephrin A3 (EphA3), a member of the ephrin receptor tyrosine kinase family, is involved in a variety of functions in normal cells, especially during embryonic development, and alterations in its expression profile have been observed in several human cancers. However, there are no reports of the expression of EphA3 in normal, hyperplastic or neoplastic canine prostate tissue or in other types of canine tumours. Six normal, 15 hyperplastic and 21 neoplastic canine prostates were examined immunohistochemically with a polyclonal antibody specific for human EphA3. The percentage of positive cells in all prostatic carcinomas was increased, with a mean of 89.28 ± 5.18% compared with normal (9.17 ± 6.72%) and hyperplastic prostates (20.00 ± 8.28%). EphA3 expression was not correlated with the histological subtypes of prostate cancer or with the Gleason score. The increase in EphA3 expression in canine prostatic carcinomas suggests the involvement of this receptor in prostatic carcinogenesis and its potential use as a target for new therapeutic strategies.

Paraneoplastic neutrophilic leukocytosis syndrome in a cat with recurrent mammary carcinoma

Case summary

A spayed 12-year-old female domestic shorthair cat presented with nodular lesions on the ventral-right thoracic wall after complete mastectomy 4 months previously. The prior diagnosis was tubulopapillary mammary carcinoma with axillary lymph node metastasis, and a recurrence was confirmed. A gradual and sequential increase in the total number of leukocytes with severe neutrophilia (95.632/µl) developed over the course of the illness, along with an increase in the size of the recurrent mass. The severe leukocytosis did not show any response to antibiotic therapy, and no evidence of infection was observed. Bone marrow cytology confirmed hypercellularity in the myeloid cell lineage. Based on these findings, paraneoplastic neutrophilic leukocytosis syndrome was suspected. An incisional biopsy of the recurrent mass was consistent with recurrent tubulopapillary mammary carcinoma. Malignant epithelial cells stained positive upon immunohistochemistry for granulocyte–macrophage colony-stimulating factor, cytokeratin and vimentin. After the final diagnosis of paraneoplastic neutrophilic leukocytosis syndrome, the cat was euthanized at the owner’s request.

Relevance and novel information

This is a novel case of paraneoplastic leukocytosis syndrome associated with mammary carcinoma in a cat. Although there are some reports describing paraneoplastic leukocytosis in cats, the relationship between this syndrome and feline mammary tumors has not been described.

Alterations of C-MYC, NKX3.1, and E-cadherin expression in canine prostate carcinogenesis

The dog (canis lupus familiaris) is the only other species besides humans that develop spontaneous prostatic carcinomas (PCa) at a high frequency. The canine model is primarily utilized for the study of the PCa molecular mechanisms and provides a natural animal model for the study of potential therapies. In humans, the PCa frequently exhibits mutations in the C-MYC and a reduced expression of the E-cadherin and NKX3.1 proteins. This study's objective was to evaluate the NKX3.1, C-MYC, and E-cadherin expression in the canine normal prostate, benign prostatic hyperplasia (BPH), proliferative inflammatory atrophy (PIA) and PCa and to verify differences in expression and subcellular localization of these proteins in the prostatic carcinogenesis. A tissue microarray (TMA) slide was constructed, and immunohistochemistry with antibodies raised against C-MYC, NKX3.1, E-cadherin and p63 was performed using the peroxidase and DAB methods. The C-MYC protein expression was elevated in the cytoplasm and nuclei of the canine PCa and PIA compared with the normal prostate (P = 0.004. The NKX3.1 protein expression was reduced in 94.75% of the PCa and 100% of the PIA compared with the normal prostate (P = 0.0022). In fact, the expression of E-cadherin trended towards a decrease in carcinomas when compared to normal prostate and PIA. By immunohistochemistry, more p63-positive basal cells were observed in the PCa and PIA when compared with the normal prostate (P = 0.0002). This study has demonstrated that the carcinogenesis of canine prostatic tissue may be related to basal cell proliferation, the gain of C-MYC function and the loss of NKX3.1 protein expression.

Abstract 1553: Down-expression of ATM gene and protein associated with canine breast tumors

Background: Ataxia telangiectasia mutated (ATM) gene encodes a protein associated with DNA damage repair that plays an important role in the maintenance of genome integrity. ATM transcript and protein down-regulation have been reported in sporadic breast carcinomas and the absence of ATM protein expression was also significantly associated with distant metastasis in women, but the mechanisms involved in the ATM deregulation are not well established.

Aim: Due to the fact that mammary tumor biological behavior is similar between canine and humans, we evaluate ATM gene and protein expression in canine breast cancer and compared with normal mammary gland from dogs.

Patients and methods: Fresh samples of non-metastatic (n=23) and metastatic mammary carcinomas (n=11) and normal breasts (n=10) were evaluated for ATM gene expression by RT-qPCR and from the same animals, another sample of tumor was collected, formalin-fixed and paraffin-embedded to assess ATM protein expression by immunohistochemistry. Evaluation of ATM protein expression was performed by the distribution of positively-immunostained tumor cells in scores: 1 (&lt;25% cells positive), 2 (26% to 50% cells positive) and 3 (&gt;51% cells positive).

Results: Down expression of ATM was detected in tumors samples (non-metastatic and metastatic mammary carcinomas) when compared to normal breast samples (P= 0,0414). Additionally, scores 1 and 2 of ATM protein expression were exclusively observed in metastatic tumors presenting score 1: 18% (2 out of 11), score 2: 55% (6 out to 11) and non metastatic tumors presenting the same score 1 and 2: 17% (4 out to 23) while all normal breast tissues showed score 3 (P=0,0087).

Conclusions: Down expression of ATM transcript was confirmed by ATM protein expression. Low levels of ATM suggest an involvement of DNA damage repair transcript and protein in tumorigenesis process of canine mammary tumors, as in women, corroborating for the use of dogs as a natural comparative model to study mammary gland tumors in humans.

Citation Format: Talita Mariana Morata Raposo, Renata C. Bueno, Márcio de Carvalho, Carlos E. Fonseca-Alves, Mirela Tinucci-Costa, Andrigo B. De Nardi, Silvia R. Rogatto, Renée Laufer-Amorim. Down-expression of ATM gene and protein associated with canine breast tumors. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 1553. doi:10.1158/1538-7445.AM2013-1553

Impact of introduced Nile tilapia (Oreochromis niloticus) on non-native aquatic ecosystems

The global invasion of non-native aquatic ecosystems by Nile tilapia (Oreochromis niloticus) is well documented and coincides with their increased use as an aquaculture species. Aquaculture can be defined as the farming of fish or other aquatic organisms and it varies considerably in terms of production practices. Generally, freshwater finfish, such as Nile tilapia, are reared in inland ponds (closed systems). However, in several countries, floating cages are increasingly used to rear Nile tilapia in open water bodies. In such systems, escape is inevitable. The Nile tilapia is considered an omnivorous species and it ingests zooplankton, phytoplankton, or debris present in rivers. As a consequence, the release of Nile tilapia into non-native aquatic ecosystems may result in competition for food and space, thereby damaging native species. The wide environmental tolerance and high reproductive rate of Nile tilapia facilitate its use for aquaculture, but also render the species highly invasive. Here, we review the high frequency of Nile tilapia in non-native biodiversity and indicate the existence of the species under feral conditions in every country in which it has been introduced through farming systems.