Lapatinib antitumor effect is associated with PI3K and MAPK pathway: An analysis in human and canine prostate cancer cells

The aberrant activation of HER2 has a pivotal role in bone metastasis implantation and progression in several tumor types, including prostate cancer (PC). Trastuzumab and other anti-HER2 therapies, such as lapatinib, have been used in human breast cancer HER2 positive. Although HER2 overexpression has been reported in PC, anti-HER2 therapy response has revealed conflicting results. We investigated the potential of lapatinib in inhibiting cell migration and inducing apoptosis in two human (LNCaP and PC3) and two canine PC cell lines (PC1 and PC2). Cell migration and apoptosis were evaluated by Annexin V/PI analysis after lapatinib treatment. The transcriptome analysis of all cell lines before and after treatment with lapatinib was also performed. We found increased apoptosis and migration inhibition in LNCaP cells (androgen-sensitive cell line), while PC1, PC2, and PC3 cells showed no alterations after the treatment. The transcriptome analysis of LNCaP and PC3 cell lines showed 158 dysregulated transcripts in common, while PC1 and PC2 cell lines presented 82. At the doses of lapatinib used, we observed transcriptional modifications in all cell lines. PI3K/AKT/mTOR pathway were enriched in human PC cells, while canine PC cells showed enrichment of tyrosine kinase antitumor response and HER2-related pathways. In canine PC cells, the apoptosis failed after lapatinib treatment, possibly due to the downregulation of MAPK genes. Prostate cancer cells insensitive to androgens may be resistant to lapatinib through PI3K gene dysregulation. The association of lapatinib with PI3K inhibitors may provide a more effective antitumor response and clinical benefits to PC patients.

Background and common lesions in the female reproductive organs of giant anteaters (Myrmecophaga tridactyla)

The giant anteater (Myrmecophaga tridactyla) is a vulnerable species in South America and is considered endangered or near extinction in Central America. Therefore, studies describing the reproductive characteristics of this species are pivotal for its conservation. Thus, this study aimed to provide a morphological description of the female reproductive tissues of this species. We collected tissue samples from six female giant anteaters and performed gross, morphological, and histochemical analyses. Five adult subjects and one juvenile were included in the study. In the ovary, classifications were made according to the follicle and oocyte sizes: primordial, primary, secondary, early antral, or antral. Typical follicles with a single oocyte surrounded by a simple or stratified layer of cubic epithelium, atretic follicles, corpora lutea, corpora albicans, and ovarian cysts were also observed. No ovarian lesions were observed. By contrast, endometritis, metritis, mucometra, and endometrial cysts were identified in the uterus. Uterine alterations in these subjects were frequent and could affect reproduction.

Biocompatibility of hydrogel derived from equine tendon extracellular matrix in horses subcutaneous tissue

Tendinopathies account for a substantial proportion of musculoskeletal injuries. To improve treatment outcomes for partial and total tendon ruptures, new therapies are under investigation. These include the application of mesenchymal stem cells (MSCs) and biocompatible scaffolds derived from the Extracellular Matrix (ECM). Synthetic polymer hydrogels have not demonstrated results as promising as those achieved with ECM hydrogels sourced from the original tissue. This study aimed to evaluate the biocompatibility of a hydrogel formulated from equine tendon ECM. Six horses were administered three subcutaneous doses of the hydrogel, with a saline solution serving as a control. Biopsies were conducted on days 7, 14, and 56 post-application to gauge the hydrogel's impact. Throughout the experiment, the horse's physical condition remained stable. Thermographic analyses revealed a temperature increase in the treated groups compared to the control group within the initial 12 h. The von Frey test, used to measure the mechanical nociceptive threshold, also showed significant differences between the treated group and the control group at 6 h, 21 days, and 28 days. Histopathological analyses identified an inflammatory response on day 7, which was absent on days 14 and 56. Transmission electron microscopy indicated a decrease in inflammatory cellularity, while immunohistochemistry staining suggested an increased presence of inflammatory factors on day 14. In summary, the hydrogel is easily injectable, triggers a temporary local inflammatory response, and integrates into the adjacent tissue from day 14 onwards.

Is Osteopontin a Good Marker for Bone Metastasis in Canine Mammary Gland Tumor and Prostate Cancer?

Osteopontin (OPN) is a protein synthesized by a large number of cells, and its overexpression has been associated with the development and prognosis of cancer. OPN overexpression has been claimed to be a marker for the development of bone metastasis in human cancers, but no prior research has investigated the association between OPN expression and the metastasis of canine mammary gland tumors (MGTs) and prostate cancer (PC). Therefore, we investigated OPN expression in MGTs and PC samples from 50 canine patients with or without metastasis (bone vs. other sites). Higher OPN expression was detected in primary tumor samples from animals with bone metastasis than in those without bone involvement (p = 0.0321). In MGT samples, a significantly lower survival rate was observed in patients with higher OPN expression (p = 0.0171). In animals with PC, there was a strong trend toward lower survival in animals with positive OPN expression; however, this trend was not statistically significant (p = 0.0779). From these findings, it can be concluded that OPN may be a promising target for future MGTs and PC studies because of its role in enhancing cell invasion and metastasis.

Proposing Clinicopathological Staging and Mitotic Count as Prognostic Factors for Canine Soft Tissue Sarcomas

Soft tissue sarcomas (STSs) are a heterogeneous group of malignant mesenchymal tumors with similar histological features and biological behaviors. They are characterized by a low to moderate local recurrence rate and low metastasis, affecting approximately 20% of patients. Although this tumor set is vital in veterinary medicine, no previous unified staging system or mitotic count has been associated with patient prognosis. Therefore, this study proposed a new clinicopathological staging method and evaluated a cut-off value for mitosis related to the survival of dogs affected by STS. This study included 105 dogs affected by STS, treated only with surgery, and a complete follow-up evaluation. The new clinicopathological staging system evaluated tumor size (T), nodal involvement (N), distant metastasis (M), and histological grading criteria (G) to categorize the tumor stage into four groups (stages I, II, III, and IV). The proposed tumor staging system was able to differentiate patients' prognoses, with dogs with stage IV disease experiencing the lowest survival time and dogs with stage I disease having the highest survival time (p < 0.001). Moreover, we assessed the median mitosis (based on mitotic count) and its association with overall survival. Our study's median mitosis was 5, and patients with ≤5 mitoses had a higher survival time (p = 0.006). Overall, the proposed staging system and mitotic count seemed promising in the prediction of patient prognosis.

Diagnosis, Prognosis, and Treatment of Canine Hemangiosarcoma: A Review Based on a Consensus Organized by the Brazilian Association of Veterinary Oncology, ABROVET

Hemangiosarcoma is a mesenchymal neoplasm originating in the endothelial cells of blood vessels; they can be classified as non-visceral and visceral types. Non-visceral hemangiosarcomas can affect the skin, subcutaneous tissues, and muscle tissues; visceral hemangiosarcomas can affect the spleen, liver, heart, lungs, kidneys, oral cavity, bones, bladder, uterus, tongue, and retroperitoneum. Among domestic species, dogs are most affected by cutaneous HSA. Cutaneous HSA represents approximately 14% of all HSA diagnosed in this species and less than 5% of dermal tumors, according to North American studies. However, Brazilian epidemiological data demonstrate a higher prevalence, which may represent 27 to 80% of all canine HSAs and 13.9% of all skin neoplasms diagnosed in this species. Cutaneous HSA most commonly affects middle-aged to elderly dogs (between 8 and 15 years old), with no gender predisposition for either the actinic or non-actinic forms. The higher prevalence of cutaneous HSA in some canine breeds is related to lower protection from solar radiation, as low skin pigmentation and hair coverage lead to greater sun exposure. Actinic changes, such as solar dermatosis, are frequent in these patients, confirming the influence of solar radiation on the development of this neoplasm. There are multiple clinical manifestations of hemangiosarcoma in canines. The diagnostic approach and staging classification of cutaneous HSAs are similar between the different subtypes. The definitive diagnosis is obtained through histopathological analysis of incisional or excisional biopsies. Cytology can be used as a presurgical screening test; however, it has little diagnostic utility in cases of HSA because there is a high risk of blood contamination and sample hemodilution. Surgery is generally the treatment of choice for dogs with localized non-visceral HSA without evidence of metastatic disease. Recently, electrochemotherapy (ECT) has emerged as an alternative therapy for the local ablative treatment of different neoplastic types; the use of radiotherapy for the treatment of dogs with cutaneous HSA is uncommon. There is greater consensus in the literature regarding the indications for adjuvant chemotherapy in subcutaneous and muscular HSA; doxorubicin is the most frequently used antineoplastic agent for subcutaneous and muscular subtypes and can be administered alone or in combination with other drugs. Other therapies include antiangiogenic therapy, photodynamic therapy, the association of chemotherapy with the metronomic dose, targeted therapies, and natural products. The benefits of these therapies are presented and discussed. In general, the prognosis of splenic and cardiac HSA is unfavorable. As a challenging neoplasm, studies of new protocols and treatment modalities are necessary to control this aggressive disease.

Immunology of Canine Melanoma

Malignant melanoma is one of the most important tumors in dogs and is highly metastatic and aggressive disease. In recent years, molecular knowledge regarding canine melanoma has increased, and some chromosomal imbalances and tyrosine kinase pathways have been identified to be dysregulated. Mxoreover, canine melanoma is an immunogenic tumor that provides opportunities to administer immunotherapy to the patient. Podoplanin and chondroitin sulfate proteoglycan-4 (CSPG4) are markers against which monoclonal antibodies have been developed and tested in dogs in vivo with promising results. Owing to the importance of canine melanoma in the veterinary oncology field, this chapter reviews the most important aspects related to immunological involvement in the prognosis and treatment of canine melanoma.

Caveolin-1, GATA-3, and Ki67 expressions and their correlation with pathological findings in canine bladder urothelial carcinoma

The bladder urothelial carcinoma (UC) represents ~2% of malignant neoplasms in dogs and is a therapeutic challenge in veterinary medicine. Although it is considered the most common bladder cancer in dogs, few previous studies have investigated different markers that correlate with clinical and pathological parameters. Therefore, this study aimed to evaluate Caveolin-1, GATA-3, and Ki67 immunostaining in canine UC samples to evaluate their correlations with histopathological variables. Thirty tumor samples were obtained, and Caveolin-1, GATA-3, and Ki67 expression was assessed by immunohistochemistry and associated with pathological factors by univariate and multivariate analyses. Among the histopathological findings, lymphatic invasion was identified in 53.33% of the tumors, and the mean mitotic count (MC) was 31.82 ± 26.26. Caveolin-1 showed mild-to-high cytoplasmic expression in neoplastic cells, whereas GATA-3 showed mild-to-high nuclear expression. The Ki67 expression revealed a mean of 24.14 ± 16.88% positive cells. In the univariate analysis, no association was found between each marker and the pathological findings. On the other hand, in multivariate analysis, we identified a positive correlation between GATA-3 and MC and a negative correlation between Caveolin-1 and MC. Moreover, lymphatic invasion was positively correlated with histological type and grade, and negatively correlated with MC. In addition, the histological type was positively correlated with the histological grade. Overall, our results indicate that Caveolin-1 and GATA-3 expression could be promising markers for bladder UC aggressiveness.

Mutational Signature and Integrative Genomic Analysis of Human Papillomavirus-Associated Penile Squamous Cell Carcinomas from Latin American Patients

Simple Summary

DNA sequencing has been crucial to comprehending cancer mutational patterns, leading to the identification of driver genes and altered signaling pathways. Thus, identifying new pathogenic variants and their impact on tumor onset, progression, and treatment response has fueled tumor biology research. Here, we present novel findings addressing the first whole-exome sequencing (WES) of human papillomavirus (HPV)-associated penile squamous cell carcinoma (PSCC) from Latin Americans and its association with pathogenesis. We also compared the molecular profile of the tumors to that of three previous studies from populations with different genetic and socioeconomic backgrounds, the majority of which was HPV-negative. We describe the most altered genes and the main pathogenic variants found in the Latin Americans, ten of which are exclusive to our study sample. The data allowed us to identify molecular pathways and druggable targets with potential treatment value for this still-neglected HPV-associated carcinoma.

Abstract

High-throughput DNA sequencing has allowed for the identification of genomic alterations and their impact on tumor development, progression, and therapeutic responses. In PSCC, for which the incidence has progressively increased worldwide, there are still limited data on the molecular mechanisms involved in the disease pathogenesis. In this study, we characterized the mutational signature of 30 human papillomavirus (HPV)-associated PSCC cases from Latin Americans, using whole-exome sequencing. Copy number variations (CNVs) were also identified and compared to previous array-generated data. Enrichment analyses were performed to reveal disrupted pathways and to identify alterations mapped to HPV integration sites (HPVis) and miRNA–mRNA hybridization regions. Among the most frequently mutated genes were NOTCH1, TERT, TTN, FAT1, TP53, CDKN2A, RYR2, CASP8, FBXW7, HMCN2, and ITGA8. Of note, 92% of these altered genes were localized at HPVis. We also found mutations in ten novel genes (KMT2C, SMARCA4, PTPRB, AJUBA, CR1, KMT2D, NBEA, FAM135B, GTF2I, and CIC), thus increasing our understanding of the potential HPV-disrupted pathways. Therefore, our study reveals innovative targets with potential therapeutic benefits for HPV-associated PSCCs. The CNV analysis by sequencing (CNV-seq) revealed five cancer-associated genes as the most frequent with gains (NOTCH1, MYC, NUMA1, PLAG1, and RAD21), while 30% of the tumors showed SMARCA4 with loss. Additionally, four cancer-associated genes (CARD11, CSMD3, KDR, and TLX3) carried untranslated regions (UTRs) variants, which may impact gene regulation by affecting the miRNAs hybridization regions. Altogether, these data contribute to the characterization of the mutational spectrum and its impact on cellular signaling pathways in PSCC, thus reinforcing the pivotal role of HPV infection in the molecular pathogenesis of these tumors.

A Review on Canine and Feline Prostate Pathology

Prostatic diseases are very common in male dogs, accounting for 3–10% of cases submitted to the veterinary practitioners. Commonly reported canine prostatic disorders include prostatic hyperplasia, prostatitis, prostatic cysts and prostatic carcinoma. However, clinical signs may be non-specific, or many cases are asymptomatic, thus leading to a difficult estimation of the actual prevalence of clinical cases. On the other side, because of the rare occurrence of prostate disease in cats, very little is known about pathogenesis, diagnostic approaches and treatment. The goal of this review is to provide detailed clinical and pathological overview of the feline and canine prostatic pathology, including the most up-to-date classification systems and histological findings. Emphasis is places on gross, cytological and histological features that are critical to reach a definitive diagnosis for a proper treatment and prognosis.

Comparative Pathobiology of Canine and Human Prostate Cancer: State of the Art and Future Directions

First described in 1817, prostate cancer is considered a complex neoplastic entity, and one of the main causes of death in men in the western world. In dogs, prostatic carcinoma (PC) exhibits undifferentiated morphology with different phenotypes, is hormonally independent of aggressive character, and has high rates of metastasis to different organs. Although in humans, the risk factors for tumor development are known, in dogs, this scenario is still unclear, especially regarding castration. Therefore, with the advent of molecular biology, studies were and are carried out with the aim of identifying the main molecular mechanisms and signaling pathways involved in the carcinogenesis and progression of canine PC, aiming to identify potential biomarkers for diagnosis, prognosis, and targeted treatment. However, there are extensive gaps to be filled, especially when considering the dog as experimental model for the study of this neoplasm in humans. Thus, due to the complexity of the subject, the objective of this review is to present the main pathobiological aspects of canine PC from a comparative point of view to the same neoplasm in the human species, addressing the historical context and current understanding in the scientific field.

Pituitary Carcinoma in a Bitch: Clinical, Tomographic, Histopathological and Immunohistochemistry Findings

Background: Primary pituitary carcinoma is rarely reported in dogs and only few reports describe its malignancy. In veterinary literature, primary pituitary carcinomas correspond up to 2.4% to 3.4% of intracranial neoplasms found in dogs and information regarding its biological behavior is quite limited.  In humans, primary pituitary carcinomas represent less than 1.0% of all tumors found in the pituitary gland. The proposed classification for pituitary carcinoma in humans and dogs determines that the tumor must have its origin in adenohypophyseal region and disseminated metastasis by cerebrospinal fluid or systemically to other organs must be observed. In dogs, a few reports have described primary pituitary carcinoma. The goal of this report was to describe clinical, tomographic, histopathological and immunohistochemistry features of a dog with primary pituitary carcinoma with adjacent invasion. Case: A 7-year-old female spayed Golden Retriever dog was assessed by general practice due progressive weight loss, muscular atrophy, lethargy, blindness, head pressing, and hyporexia for 21 days. Computed tomography (CT) showed a cerebral parenchyma with expansive extra-axial base formation, originating from sella turcica topography, measuring about 2.0 centimeter dorsally, displacing the third ventricle, suggesting the diagnosis of pituitary neoplasia. The hormones thyroid-stimulating hormone (TSH) and total thyroxine (T4) as well as stimulation ACTH test were unremarkable. After 7 days, neurological clinical signs progressed and unfortunately the patient died ten days later after hospitalization. A necropsy exam revealed pituitary gland with increased dimensions (2.5 x 2.0 cm). Histopathological findings revealed tumor proliferation in pituitary gland. The neoplasm showed invasion to the nervous parenchyma and metastatic foci between the brain lobes. Immunohistochemistry was positive for keratin and neuron-specific enolase and negative for epithelial membrane antigen, S-100 protein, glial fibrillary acidic protein, estrogen receptor, CD34, chromogranin, somatostatin, and ACTH. The clinical, histopathological and immunohistochemistry findings supported the diagnosis of primary pituitary carcinoma. Discussion: There is lack information regarding pituitary carcinoma prevalence in dogs, and little is known about its pathological and clinical features. The patient showed a shorter survival time (30 days after the onset of clinical signs) for a non-hormonally functional tumor that presented with acute onset of neurological signs due to local effect of an expanding mass, also described in others pituitary carcinoma reports. It was observed a metastatic focus of pituitary neoplasia between cerebral hemispheres, leading us to conclude to be a pituitary carcinoma. Adjacent infiltration was noticed by the presence of neoplasm invasion to the synoptic nervous parenchyma and metastatic foci between the brain lobes as well as the presence of a non-delimited nodular area of neoplastic implantation between the cerebral hemispheres, and optic nerve compromised by neoplasm cells. The data reported here showed that a negative ACTH receptor in neoplasm with 10% Ki-67 proliferation index with no history of clinical signs of pituitary-dependent hyperadrenocorticism (PDH). Pituitary adenocarcinomas are thought to be more often non-secretors. CT findings reveled a pituitary mass of 2.5 cm in vertical height suggesting a pituitary macrotumor although there is lack of description for pituitary carcinomas in veterinary literature. The animal had a fast deterioration of his clinical condition and quickly came to death, suggesting poor biological behavior of the tumor. Keywords: adrenocorticotropic hormone, case report, dog, pituitary tumors.

Primary Perianal Malignant Melanoma in a Dog - Combination Therapy

Background: Melanocytic neoplasm can arise from melanocytes in any location of the body. Malignant melanoma (MM) has a poor prognosis in dogs and presence of lymphvascular invasion, distant metastasis, or mitotic activity present prognostic value. Primary melanoma affecting the gastrointestinal tract has been rarely reported in veterinary literature, thus the prognosis affecting gastrointestinal tract is unknown. Electrochemotherapy (ECT) is an effective local treatment which combines chemotherapeutic drugs mainly bleomycin or cisplatin followed by the delivery of permeabilizing electrical pulses However, other hydrophilic drugs seem to present an increase cytotoxic effect such as carboplatin.Case: A 9-year-old mixed-breed neutered dog was referred to a private clinic with a mass in the perianal region diagnosed as perianal melanoma. No metastasis was observed on abdominal ultrasound nor chest x-ray (3 views). Clinical signs noted were tenesmus, hemorrhagic discharge, weight loss and hyporexia. Considering the tumor volume (16.0 x 10.0 cm), a neoadjuvant ECT session was proposed. The authors opted for carboplatin (300 mg/m², intravenously), administered over 20 min and cisplatin intratumorally (1 mg/cm³, equivalent to 1 mL/1cm³; total volume 20 mL) administered in the upper parts of the mass that could be reached while avoiding drug leakage. After administration, sequences of eight biphasic pulses, (100 microseconds), with a voltage ranging from 650-1,000V/cm (pulse generator Onkodisruptor®) using a hexagonal/single pair and plate electrode were delivered. At day 30th, a partial response was observed accordingly to RECIST system, with tumor size of 5.0 x 5.0 cm (65.4 cm³). A second ECT session was performed with the same previous protocol, but with a decreased dosage of carboplatin (240 mg/m² consistent with 20% reduction) due to adverse effects in the first session, resulting in stable disease at day 60th (30 days after second ECT). Then, we proposed a surgical excision of the mass including partial resection of ventral rectum with intraoperative ECT. Afterwards, it was observed fecal incontinence that did not resolved after time but did not significant cause a morbidity in the patient. Patient achieved a disease-free interval (DFI) of 700 days and survival time of 730 days. Unfortunately, patient died due to distant metastasis.Discussion: Surgery is still the cornerstone treatment for MM in dogs, regardless anatomic site. However, in perianal region, wide or radical local surgical excision is a challenge due to anatomic region which precluded most of the time to achieve complete margins. In this report, the origin of the tumors was not defined since no normal tissue was found surrounding tumors cells probably due to tumor invasion and destruction of surrounding tissue. Thus, based on the previous literature, this tumor could have been arisen from rectum wall or anal sac. The longer DFI and survival time from this patient is superior from the most veterinary cases in literature which combined different types of treatment such as surgery, chemotherapy, immunotherapy, palliative care or ECT. Neoadjuvant ECT leaded to a reliable approach for partial remission in order to perform a better surgical approach in this case report. To conclude, ECT may be an option for partial remission and local control in regions which anatomic limitation is a challenge for wide excision.Keywords: bleomycin, carboplatin, cisplatin, electroporation, melanocytic tumor.

P-Glycoprotein and Androgen Receptor Expression Reveals Independence of Canine Prostate Cancer from Androgen Hormone Stimulation

Canine prostate cancer (PC) is an aggressive disease, and dogs can be considered comparative models for human PC. In recent years, canine PC has been shown to resemble human castrate-resistant prostate cancer. The influx and efflux of testosterone in prostatic luminal cells are regulated by P-glycoprotein (P-gp). Therefore, human PC generally lacks P-gp expression and maintains the expression of androgen receptors (ARs). However, this co-expression has not previously been investigated in dogs. Therefore, this study aimed to evaluate AR and P-gp co-expression to elucidate these protein patterns in canine prostate samples. We identified AR/P-gp double immunofluorescence co-expression of both proteins in normal luminal cells. However, in canine PC, cells lack AR expression and exhibit increased P-gp expression. These results were confirmed by gene expression analyses. Overall, our results strongly suggest that normal canine prostate testosterone influx may be regulated by P-gp expression, and that during progression to PC, prostatic cells lack AR expression and P-gp overexpress. P-gp expression in canine PC may be related to a phenotype of multiple drug resistance.

Influence of Vitrification Device, Warming Protocol, and Subsequent In Vitro Culture on Structural Integrity of Testicular Fragments from Adult Domestic Cats

The objective of the study was to evaluate the integrity of cat testicular tissues after vitrification with different devices followed by different warming conditions. The influence of vitro culture for 24 hours after warming also was examined. Testicular tissues from adult domestic cats were dissected in small fragments that were vitrified using Cryotop^® or threaded on fine needles, warmed (directly at 37°C or with a preliminary 10 seconds exposure to 50°C), and/or cultured in vitro for an additional 24 hours. For each treatment group, tissues were assessed based on histology, apoptosis, and sperm DNA integrity. Results showed that fragments of testicular tissues were efficiently cryopreserved (maintaining the quality of all cell types) with vitrification with Cryotop followed by direct warming at 37°C, and additional culture of 24 hours at 38.5°C. These encouraging results are paving the road to optimize preservation protocols and use them for systematic banking of tissues from genetically valuable felids.

The use of flow cytometry for diagnosis and immunophenotyping in chronic lymphocytic leukemia in a dog: Clinical case report

Background

Chronic lymphocytic leukemia (CLL) is the most common type of leukemia in dogs. It is characterized by the proliferation of neoplastic lymphocytes in the bone marrow, which are morphologically normal (mature), but non-functional. CLL in canines commonly originates in cytotoxic T lymphocytes (TCD8⁺), and although there is controversy regarding the prognostic value of the immunophenotype, this cell lineage may be associated with a good prognosis.

Case Description

A 10-year-old, entire female, mixed-breed dog was brought to the University Hospital of the Veterinary Faculty (UdelaR) for consultation because a routine pre-surgical check-up revealed lymphocytic leukocytosis, normocytic anemia, and hyperglobulinemia due to an oligoclonal gammopathy. The ultrasound revealed splenomegaly. PCR performed on blood was negative for Ehrlichia canis. Blood and bone marrow flow cytometry was performed to complement the diagnosis and carry out the immunophenotype, which showed CLL of CD8⁺ T-cell lineage. The clinical suspicion of CLL was confirmed by a myelogram. Chemotherapy treatment based on alkylating agents and glucocorticoids was established. So far, the patient has an overall survival of 13 months with a good response to treatment.

Conclusion

The combination of the immunophenotyping test, the myelogram, and the hematological and biochemical profile confirmed the presence of T-CLL in our patient. Flow cytometry, increasingly used in veterinary medicine, allowed us to confirm the diagnosis of CLL originating in cytotoxic T lymphocytes in our patient, through the presence of positive staining of primary antibodies specific for the canine species CD45, CD3, CD5, and CD8 and the absence of staining for CD4, CD21, and CD34.

Epidemiological characterization of notified human brucellosis cases in Southern Brazil

Brucellosis is one of the most important and widespread bacterial zoonotic diseases worldwide, and it is transmitted to humans from various sources, including direct contact with infected animals and the ingestion of contaminated products, including unpasteurized milk. There are only a few epidemiological studies on said disease in humans in Western Santa Catarina, a region instantiated by agriculture. Thus, the objective of this study was to characterize the epidemiological aspects of human brucellosis reported in Western Santa Catarina from 2013 to 2018. The data were provided by the Epidemiological Surveillance Board (Diretoria de Vigilancia Epidemiologica). The frequency of the disease in humans and the epidemiological profile of confirmed human cases were evaluated. Cases that were screened positive and those that were confirmed and submitted to the therapeutic protocol were analyzed. During the study period, 3,671 people were tested, of which 12.34% were screened positive (453/ 3,671) and 3.40% were confirmed (125/3,671). The year with the highest number of people testing positive was 2015 (123 cases), and 2018 was the year with the highest number of confirmed cases (39 cases). Confirmed cases predominated in males (48.8%), self-declared white (22.4%), aged 20-59 years old (60%), with incomplete primary education (22.4%), of rural origin (59.2%), with occupational contact with cattle (64.8%), engaged in professions directly linked to agricultural and livestock activities (55.5%), and who reported consumption of unpasteurized dairy products (59.2%). No seasonal variation was observed in case numbers. The results demonstrated that brucellosis is an endemic disease in Western Santa Catarina.

Experimental transmission of Leishmania (Leishmania) amazonensis to immunosuppressed mice through the bite of Lutzomyia longipalpis (Diptera: Psychodidae) results in cutaneous leishmaniasis

Lutzomyia longipalpis is the natural vector of Leishmania (Leishmania) infantum, but it is also permissive for several Leishmania species that are related to cutaneous leishmaniasis (CL). Maranhao State (Northeast of Brazil) is endemic for CL and has the highest number of cases of diffuse cutaneous leishmaniasis (DCL) in the country. It is a rare disease associated with a defective immune response mainly caused by L. (L.) amazonensis. Additionally, the number of immunosuppressed patients infected with the etiologic agents of CL has increased, including regions in which the main vectors of CL are rare. Therefore, we investigated whether Lu. longipalpis is able to transmit L. (L.) amazonensis to uninfected and immunosuppressed mice, resulting in CL. For that, 291 sand flies took an initial blood meal in mice infected with L. (L.) amazonensis. Of these, 17 underwent a second feeding on uninfected and immunosuppressed mice (of which 58.8% were also positive for Leishmania according to data on the dissection of the intestine). After 27 days of infection, these mice exhibited leishmaniotic lesions. The occurrence of parasites on the animal’s skin was confirmed by limiting dilution and immunohistopathological analyses. Parasite DNA was also detected in paw lesions and inguinal lymph nodes. DNA sequencing confirmed the Leishmania species in insects and mice. The results confirmed the ability of Lu. longipalpis to become infected and experimentally transmit L. (L.) amazonensis to immunosuppressed rodents, resulting in leishmaniotic lesions. Our data open perspectives for the potential role of Lu. longipalpis in the epidemiology of urban cutaneous leishmaniasis, especially in immunosuppressed patients.

Effect of low-level laser therapy on the membrane induced by the Masquelet technique at an orthotopic site in rabbits

Purpose:

To evaluate the low-level laser therapy (LLLT) on the membrane induced by the Masquelet technique in rabbits.

Methods:

Twelve Norfolk rabbits at approximately 3 months of age were used. A 1-cm segmental defect was induced in both radii, which were filled with polymethylmethacrylate cylinder. LLLT was used postoperatively in the bone defect of one of the forelimbs every 48 hours for 15 days. Six rabbits were euthanatized on third and sixth postoperative weeks.

Results:

In both forelimbs, radiographs showed new bone growth from radius cut ends on the third postoperative week and more advanced stage on the sixth postoperative week. Ultrasound showed induced membrane one week after the surgery. Histologically, there were no significant differences in the semi-quantitative score of inflammation intensity, total number of blood vessels, bone metaplasia, and collagen. The average thicknesses were 2,050.17 and 1,451.96 μm for control membranes and 2,724.26 and 2,081.03 μm for irradiated membranes, respectively, on third and sixth postoperative weeks. Vascular endothelial growth factor A (VEGF-A) and platelet derived growth factor (PDGF) expression were present in the induced membranes of control and irradiated forelimbs, but there was no significant difference.

Conclusions:

Based on assessment methods, it was not possible to demonstrate the effect of LLLT on the induced membrane.

Expression and prognostic significance of vascular endothelial growth factor-A (VEGF-A) and its receptor in canine prostate cancer

BACKGROUND

Vascular endothelial growth factor-A (VEGF-A) and its receptor, VEGF receptor-2 (VEGFR-2), represent a complex family of angiogenic molecules consisting of different ligands and receptors. Due to the importance of VEGF-A/VEGFR-2 signaling in tumor proliferation and angiogenesis, this study aimed to evaluate the protein and gene expression levels of VEGF-A and VEGFR-2 in canine prostate cancer (PC).

METHODS

We analyzed VEGF-A and VEGFR-2 expression in 87 PC samples by immunohistochemistry and quantitative-polymerase chain reaction. PC samples were graded according to the Gleason score and the immunohistochemical staining for VEGF-A and VEGFR-2 was quantified using a selected threshold from the ImageJ Software. Microvascular density was assessed by cluster of differentiation 31 staining and counting the number of positive vessels. Additionally, the homology of VEGF-A and VEGFR-2 between humans and dogs was assessed, followed by the construction of a protein structure homology model to compare the tertiary structures of these proteins in both species.

RESULTS

Negative to weakly positive expression levels of VEGF-A and VEGFR-2 were observed in the epithelial cells of the normal prostate (NP) and prostatic hyperplasia samples. In contrast, the canine proliferative atrophy and PC samples exhibited higher VEGF-A (p < .0001) and VEGFR-2 (p < .0001) compared to NP. Moreover, positive correlations between the expression levels of VEGF-A and VEGFR-2 (Spearman's coefficient (r) = .68, p = .013) and the expression levels of VEGF-A and VEGFR-2 proteins (r = .8, p < .0001) were also observed in the NP samples. Additionally, the patients with PC exhibiting higher VEGFR-2 expression levels experienced a shorter survival period (p = .0372). Furthermore, we found an association between the microvascular density and overall survival. Dogs with a higher number of vessels showed a shorter survival time. We further demonstrated that the VEGF-A and VEGFR-2 exhibited high homology between humans and dogs, and identified their protein structures in both species.

CONCLUSIONS

In conclusion, VEGFR-2 appears to be an independent prognostic factor in animals with PC. VEGF-A and VEGFR-2 are highly conserved between humans and dogs, which can be investigated further in future cross-species studies to explore their therapeutic applications.

Lymphatic invasion is a significant indicator of poor patient outcome in canine bladder urothelial carcinoma

BACKGROUND

Urothelial carcinoma (UC), also known as transitional cell carcinoma, is the most common malignant tumor of the canine urinary bladder and represents a model for studying human bladder cancer. However, the existing literature has limited data on the clinicopathological characteristics of these tumors and their prognostic value.

AIM

The aim of this study was to evaluate such factors, correlating them with follow-up, in a group of 32 dogs with bladder UC.

METHODS

Clinical data of these cases, submitted to São Paulo State University and VetPat Private Laboratory (São Paulo/Brazil), were recorded between January 2000 and November 2019. For each case, formalin-fixed and paraffin-embedded sections were stained with hematoxylin and eosin and histologically evaluated. Survival analysis was carried out, and the prognostic value of the presence of lymphatic invasion and the treatment used was determined.

RESULTS

Dogs with neoplastic lymphatic vessel invasion had a lower overall survival compared to those without lymphatic invasion, and dogs that received vinblastine in addition to surgery had higher global survival when compared to animals that received carboplatin in addition to surgery.

CONCLUSION

The results obtained show the importance of further studies regarding the prognostic value of the two factors demonstrated as potential survival predictors, especially the lymphatic vessel invasion.

In Vitro Biological Performance of Alginate Hydrogel Capsules for Stem Cell Delivery

Encapsulation of biological components in hydrogels is a well described method for controlled drug delivery of proteins, tissue engineering and intestinal colonization with beneficial bacteria. Given the potential of tissue engineering in clinical practice, this study aimed to evaluate the feasibility of encapsulation of adipose tissue-derived mesenchymal stem cells (MSCs) of mules in sodium alginate. We evaluated capsule morphology and cell viability, immunophenotype and release after encapsulation. Circular and irregular pores were observed on the hydrogel surface, in which MSCs were present and alive. Capsules demonstrated good capacity of absorption of liquid and cell viability was consistently high through the time points, indicating proper nutrient diffusion. Flow cytometry showed stability of stem cell surface markers, whereas immunohistochemistry revealed the expression of CD44 and absence of MHC-II through 7 days of culture. Stem cell encapsulation in sodium alginate hydrogel is a feasible technique that does not compromise cell viability and preserves their undifferentiated status, becoming a relevant option to further studies of tridimensional culture systems and in vivo bioactive agents delivery.

Effects of the Latex of Synadenium grantii Hook F. (Euphorbiaceae) on a Preclinical Model of Canine Prostate Cancer

Prostatic cancer (PC) stands out in terms of its occurrence, pathophysiology, and unfavorable prognostics in humans and dogs. Natural drugs bear an integrative potential for conventional antineoplastic treatments. In this context, the bioproducts of Synadenium grantii have been empirically used in different parts of Brazil for the integrative treatment of prostate cancer in humans. However, there is no availability of scientific evidence of the antitumor effects of S. grantii. Therefore, this study aimed to investigate the bioactive compounds in the latex of S. grantii using the high-resolution mass spectrophotometry (HRMS) and to evaluate its cytotoxic effects on primary canine PC cell cultures. Four fragments of phorbol ester were identified as potential bioactive compounds using the HRMS. With the help of an MTT ([3-(4,5-dimethyldiazol-2-yl)-2,5 diphenyltetrazolium bromide]) assay, two canine prostatic carcinoma cell lines (PC 1 and PC2) showed a decrease in the tumor cell count, with an Inhibitory concentration 50 (IC₅₀)of 0.8469 and 0.6068 mg/ml, respectively, for PC1 and PC2. In conclusion, the latex of S. grantii contains phorbol esters in its composition, and its aqueous solution has a cytotoxic effect on canine metastatic PC cells in vitro.

Preparation and characterization of leukocyte- and platelet-rich fibrin membrane derived from cats' blood

Autologous platelet concentrates have been used in regenerative medicine in humans due to the abundance of growth factors, but there are only a few reports in small animals. This study aimed to prepare and characterize a leukocyte and platelet-rich fibrin membrane (L-PRF) produced with blood obtained from cats. Thirteen client-owned healthy adult Maine Coon cats were enrolled. The blood samples were collected and centrifuged at 650g for 12 min using a centrifuge specifically designed for this application. The L-PRF clot was removed from the tube and red blood cell base layer was separated, leaving buffy coat intact. After this, L-PRF clot was compressed by specialized metal plate for 30-60 s, and L-PRF membrane was obtained. Light microscopy examination of the membranes showed three distinct layers: white part, buffy coat, and red part. Immunohistochemical analysis demonstrated expression of vascular endothelial growth factor and platelet derived growth factor. The scanning electron microscopy showed that three-dimensional architecture of fibrin network was more compact in the area near the buffy coat. In conclusion, the method used allowed the characterization of the L-PRF membrane composition, which presented cell types and fibrin network architecture similar to those described in the human species.

A Comparative Meta-Analysis and in silico Analysis of Differentially Expressed Genes and Proteins in Canine and Human Bladder Cancer

Canine and human bladder cancer present similar anatomical, morphological, and molecular characteristics, and dogs can be considered a model for human bladder cancer. However, the veterinary literature lacks information regarding cross-validation analysis between human and canine large-scale data. Therefore, this research aimed to perform a meta-analysis of the canine literature on bladder cancer, identifying genes and proteins previously evaluated in these studies. In addition, we also performed a cross-validation of the canine transcriptome data and the human data from The Cancer Genome Atlas (TCGA) to identify potential markers for both species. The meta-analysis was performed using the following indexing terms: “bladder” AND “carcinoma” AND “dog” in different international databases, and 385 manuscripts were identified in our initial search. Then, several inclusion criteria were applied, and only 25 studies met these criteria. Among these studies, five presented transcriptome data, and 20 evaluated only isolated genes or proteins. Regarding the studies involving isolated protein analysis, the HER-2 protein was the most studied (3/20), followed by TAG-72 (2/20), COX-2 (2/20), survivin (2/20), and CK7 (2/20), and the remaining nine studies evaluated one isolated protein each. Regarding the cross-validation analysis of human and canine transcriptome data, we identified 35 dysregulated genes, including ERBB2, TP53, EGFR, and E2F2. Our results demonstrate that the canine literature on bladder cancer previously focused on the evaluation of isolated markers with no association with patient survival. This limitation may be related to the lack of a homogenous protocol for treating patients and the lack of follow-up during treatment. In addition, the lack of information regarding tumor muscle invasion can be considered an important limitation when comparing human and canine bladder tumors. Our in silico analysis involving canine and human transcriptome data provided several genes with the potential to be markers for both human and canine bladder tumors, and these genes should be considered for future studies on canine bladder cancer.

Preliminary assessment of electrochemotherapy feasibility in dogs with vesical transitional cell carcinoma

Electroporation is a technique that increases the uptake of chemotherapeutic drugs by tumors. Electrochemotherapy (ECT) has been successfully used to treat solid tumors. Recently, novel applications have been explored in the treatment of visceral tumors. This report aimed to describe the ECT as an approach to vesical carcinoma in three dogs. The patients received ECT with bleomycin as an intravenous bolus and intra-lesional cisplatin (cases 2 and 3). The ECT was performed by electroporator (Onkodisruptor^®) using a plate and/or a single pair needle array electrode. Case 1 was a 7-year-old female Pitbull dog with a history of hematuria and stranguria. The ECT was performed during cystotomy using a single pair array electrode. However, the patient developed uroabdomen two days post-ECT and died 5 days later. Case 2 was a 12-year-old female Poodle dog with hematuria, dysuria, and pollakiuria. Cystotomy and ECT were performed using plate array electrodes. Complete remission of the intra-luminal mass was observed 11 days post-ECT. However, 21 days after the procedure, an acute unilateral renal failure occurred possibly due to a neoplastic embolus into the right ureter leading to kidney hydronephrosis, and the patient was euthanized. Case 3 was a 10-year-old female Cocker dog with hematuria and pollakiuria. The patient was fully competent after ECT without clinical signs of pollakiuria and recovered from hematuria 7 days post-ECT. The bladder returned to normal status 28 days post-ECT. The ECT was not able to increase the overall survival of the patients evaluated and should be indicated carefully.

Establishment and Characterization of Canine Mammary Gland Carcinoma Cell Lines With Vasculogenic Mimicry Ability in vitro and in vivo

Mammary tumors affect intact and elderly female dogs, and almost 50% of these cases are malignant. Cell culture offers a promising preclinical model to study this disease and creates the opportunity to deposit cell lines at a cell bank to allow greater assay reproducibility and more reliable validation of the results. Another important aspect is the possibility of establishing models and improving our understanding of tumor characteristics, such as vasculogenic mimicry. Because of the importance of cancer cell lines in preclinical models, the present study established and characterized primary cell lines from canine mammary gland tumors. Cell cultures were evaluated for morphology, phenotype, vasculogenic mimicry (VM), and tumorigenicity abilities. We collected 17 primary mammary carcinoma and three metastases and obtained satisfactory results from 10 samples. The cells were transplanted to a xenograft model. All cell lines exhibited a spindle-shaped or polygonal morphology and expressed concomitant pancytokeratin and cytokeratin 8/18. Four cell lines had vasculogenic mimicry ability in vitro, and two cell lines showed in vivo tumorigenicity and VM in the xenotransplanted tumor. Cellular characterization will help create a database to increase our knowledge of mammary carcinomas in dogs, including studies of tumor behavior and the identification of new therapeutic targets.

Response dataset from canine extramedullary plasmacytoma treated with lipophobic drugs enhanced by electroporation

Over the past 15 years, lipophobic drugs, such as bleomycin and cisplatin, have been used combined with electroporation, which promotes their uptake through the cell membrane. The present data describe general findings following electrochemotherapy and how plasmacytomas can respond to this technique. We will explain and illustrate specific outcomes during the remission process. The data presented here can be useful for researchers, veterinarians, and pet owners. Furthermore, the data could be useful for other cutaneous or oral tumors in which electrochemotherapy may be indicated. Interpretation of the data and outcomes may be found in the research article entitled "Outcome following curative-intent electrochemotherapy for extramedullary plasmocytoma in dogs - case reports ."

Germline Mutation in MUS81 Resulting in Impaired Protein Stability is Associated with Familial Breast and Thyroid Cancer

Multiple primary thyroid cancer (TC) and breast cancer (BC) are commonly diagnosed, and the lifetime risk for these cancers is increased in patients with a positive family history of both TC and BC. Although this phenotype is partially explained by TP53 or PTEN mutations, a significant number of patients are negative for these alterations. We judiciously recruited patients diagnosed with BC and/or TC having a family history of these tumors and assessed their whole-exome sequencing. After variant prioritization, we selected MUS81 c.1292G>A (p.R431H) for further investigation. This variant was genotyped in a healthy population and sporadic BC/TC tissues and investigated at the protein level and cellular models. MUS81 c.1292G>A was the most frequent variant (25%) and the strongest candidate due to its function of double-strand break repair. This variant was confirmed in four relatives from two families. MUS81 p.R431H protein exhibited lower expression levels in tumors from patients positive for the germline variant, compared with wild-type BC, and normal breast and thyroid tissues. Using cell line models, we showed that c.1292G>A induced protein instability and affected DNA damage response. We suggest that MUS81 is a novel candidate involved in familial BC/TC based on its low frequency in healthy individuals and proven effect in protein stability.

Outcome Following Curative-Intent Electrochemotherapy for Extramedullary Plasmocytoma in Dogs - Case Reports

Plasma cell tumors can occur as solitary collections referred as extramedullary plasmocytoma (EMP). The present report describes four cases of EMP treated with a local nonthermal ablative approach. Four dogs were diagnosed with extramedullary plasmocytomas (EMP) in different body regions (oral cavity, digits, and lip). Since surgical excision was declined by the owners (maxillectomy; amputation or lip reconstruction), a curative-intent approach was indicated as solely treatment- electrochemotherapy (ECT). All the patients received ECT under general anesthesia using bleomycin intravenously (15,000 UI/m²) or cisplatin intratumorally (1mg/cm³). All dogs developed transitory ulceration and swelling one-week after procedure that completely healed within 30 days post-ECT. Complete remission was achieved in all cases and lasted for 515 (oral case), 695 (one digit), 90 (another digit case) and 240 (lip) days. These results suggested that ECT promoted remission in EMP cases being a possibility for local control in dogs affected by this disease.

Investigation of the Prognostic Significance of Vasculogenic Mimicry and Its Inhibition by Sorafenib in Canine Mammary Gland Tumors

Canine mammary gland tumor (CMT) is one of the most important tumors in intact female dogs, and due its similarity to human breast cancer (BC), it is considered a model in comparative oncology. A subset of mammary gland tumors can show aggressive behavior, and a recurrent histological finding is the presence of vasculogenic mimicry (VM). VM is a process in which highly aggressive cancer cells fuse, forming fluid-conducting channels without endothelial cells. Although, VM has been described in canine inflammatory carcinoma, no previous studies have investigated the prognostic and predictive significance of VM in CMT. Thus, this research aimed to investigate the prognostic significance of VM in vivo and the capacity of sorafenib to inhibit VM in vitro. VM was identified in situ in formalin-fixed paraffin-embedded CMT samples (n = 248) using CD31/PAS double staining. VM was identified in 33% of tumors (82/248). The presence of VM was more strongly related to tumor grade than to histological subtype. Patients with positive VM experienced shorter survival times than dogs without VM (P < 0.0001). Due to the importance of the VEGF-A/VEGFR-2 autocrine feed-forward loop in epithelial tumors, we investigated the association between VEGF-A and VEGFR-2 expression by neoplastic tumor cells and the associations of VEGF-A or VEGFR-2 expression with VM. Among the VM-positive samples, all (n = 82) showed high scores (3 or 4) for VEGF-A and VEGFR-2, indicating that VM was a common finding in tumors overexpressing VEGF-A and VEGFR-2. Thus, we cultured two CMT primary cell lines with VM abilities (CM9 and CM60) in vitro and evaluated the anti-tumoral effect of sorafenib. The CM9 cell line showed a half maximal inhibitory concentration (IC50) of 2.61 μM, and the CM60 cell line showed an IC50 of 1.34 μM. We performed a VM assay in vitro and treated each cell line with an IC50 dose of sorafenib, which was able to inhibit VM in vitro. Overall, our results indicated that VM was a prognostic factor for dogs bearing CMT and that sorafenib had an inhibitory effect on VM in CMT cancer cells in vitro.

E-Cadherin Downregulation is Mediated by Promoter Methylation in Canine Prostate Cancer

E-cadherin is a transmembrane glycoprotein responsible for cell-to-cell adhesion, and its loss has been associated with metastasis development. Although E-cadherin downregulation was previously reported in canine prostate cancer (PC), the mechanism involved in this process is unclear. It is well established that dogs, besides humans, spontaneously develop PC with high frequency; therefore, canine PC is an interesting model to study human PC. In human PC, CDH1 methylation has been associated with E-cadherin downregulation. However, no previous studies have described the methylation pattern of CDH1 promoter in canine PC. Herein, we evaluated the E-cadherin protein and gene expression in canine PC compared to normal tissues. DNA methylation pattern was investigated as a regulatory mechanism of CDH1 silencing. Our cohort is composed of 20 normal prostates, 20 proliferative inflammatory atrophy (PIA) lesions, 20 PC, and 11 metastases from 60 dogs. The E-cadherin protein expression was assessed by immunohistochemistry and western blotting and gene expression by qPCR. Bisulfite- pyrosequencing assay was performed to investigate the CDH1 promoter methylation pattern. Membranous E-cadherin expression was observed in all prostatic tissues. A higher number of E-cadherin negative cells was detected more frequently in PC compared to normal and PIA samples. High-grade PC showed a diffuse membranous positive immunostaining. Furthermore, PC patients with a higher number of E-cadherin negative cells presented shorter survival time and higher Gleason scores. Western blotting and qPCR assays confirmed the immunohistochemical results, showing lower E-cadherin protein and gene expression levels in PC compared to normal samples. We identified CDH1 promoter hypermethylation in PIA and PC samples. An in vitro assay with two canine prostate cancer cells (PC1 and PC2 cell lines) was performed to confirm the methylation as a regulatory mechanism of E-cadherin expression. PC1 cell line presented CDH1 hypermethylation and after 5-Aza-dC treatment, a decreased CDH1 methylation and increased gene expression levels were observed. Positive E-cadherin cells were massively found in metastases (mean of 90.6%). In conclusion, low levels of E-cadherin protein, gene downregulation and CDH1 hypermethylation was detected in canine PC. However, in metastatic foci occur E-cadherin re-expression confirming its relevance in these processes.

Electrochemotherapy Associated with Calcium Electroporation in Metastatic Feline Cutaneous Malignant Melanoma

Background: Calcium electroporation (CaEP) is a novel therapeutic treatment that has been studied for cancer due to its selective killing cancer cells by necrosis and danger signals. Besides that, electrochemotherapy (ECT) is an effective local treatment that involves the administration of chemotherapeutic drugs followed by delivery of electrical pulses to the tumor. The combination with ECT and CaEP has been reported in literature suggesting that additional response of immune system could have been enhanced by electroporation with calcium. This case, report on the successful treatment with CaEP combined with ECT for treatment of a regional metastasis in a feline model of malignant melanoma.Case: A 9-year-old, mixed breed cat was referred to the veterinary clinic with a 2-month history of cutaneous peripalpebral plaque lesion (0.19 cm³) and a submandibular lymph node enlargement (0.5 cm³). Incisional biopsy of the cutaneous lesion and fine-needle aspiration of submandibular lymph node confirmed a cutaneous melanoma with submandibular lymph node metastasis. Tumor staging was set in T1N1M0 according to WHO staging criteria. ECT for the primary lesion and lymph node metastasis was proposed. For the ECT, bleomycin (15,000 UI/m²) application was performed intravenous followed by electroporation (8 pulses of 100 μs at 1000 V/cm, and 1 Hz) using a needle array electrode consisted of two parallel rows with six needles in each row. At 28-day post-ECT complete remission of the primary tumor and metastatic foci was achieved. However, 120 days after ECT, recurrence was observed in submandibular and retropharyngeal lymph nodes. A second ECT approach was performed adding to bleomycin the intra lymph nodal application of calcium gluconate. The dose of calcium gluconate was diluted in an isotonic 0.9% NaCl solution resulting in a low concentration at 9 mM, injected in both metastatic lymph nodes (submandibular total volume: 1.4 ml; retropharyngeal total volume: 0.5 mL) and pulses were delivered immediately after drug administration. No systemic adverse effects were observed. Local adverse effects were considered mild as transitory edema and ulceration post procedure. One-week post-ECT+CaEP, complete remission of local metastasis occurred. However, the patient achieved five months disease free interval, and died during a surgical approach, achieving nine months of survival time.Discussion: Feline cutaneous malignant melanoma is an aggressive disease with a short survival time for the patients with mean of 4.5 months. CaEP is a novel anticancer treatment that has been study in the past years due to its selective killing cancer cells by necrosis and danger signals. The CaEP induces supraphysiological calcium influx into neoplastic cells leading to acute ATP depletion and necrosis of tumor cells. This use could be an interesting therapeutic choice for both human and veterinary medicine. In this patient, it was demonstrated a good clinical response with its use, showing temporarily tumor remission from the case presented with disease free interval of five months when compared to other report of two months. This description showed that ECT associated with CaEP improved outcome of regional melanoma lymph node metastasis in a cat. However, further investigations are needed to understand the use of CaEP in patients for local control metastasis as well as evaluate the use of both modalities to determine its synergistic effect.

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.

Deregulation of VEGFR-2 and PDGFR Expression and Microvascular Density in a Triple-Negative Model of Canine Malignant Mammary Tumors with Lymph Node or Lung Metastasis

Canine mammary tumors (CMT) represent the most common cancer in noncastrated female dogs. Interestingly, triple-negative tumors are the most common molecular subtype in female dogs. In this study, we proposed to evaluate the expression of vascular endothelial growth factor receptor 2 (VEGFR-2), Platelet-derived growth factor receptor (PDGFR), and microvascular density (MVD) in a group of metastatic and nonmetastatic triple-negative CMT and compare the expression based on clinical parameters. Twenty-six female dogs with triple-negative mammary tumors were divided into three groups: nonmetastatic tumors (NMT) (n = 11), tumors with lymph node metastasis (LNM) (n = 10), and tumors with lung metastasis (LM) (n = 5). We observed increased VEGFR-2 expression in LNM compared with NMT and a positive correlation between tumor grade and VEGFR-2 expression. A positive correlation was noted between VEGFR-2 and PDGFR expression. Regarding microvascular density (MVD), we identified a higher number of vessels in primary tumors with lymph node metastasis and lung metastasis compared with tumors with no metastasis. The primary tumors with lung metastasis exhibited an increased MVD compared with carcinoma with lymph node metastasis. Overall, our results suggest a deregulation of VEGFR-2 and PDGFR and high MVD in metastatic tumors, indicating a role for angiogenesis in tumor progression.

Characterization of OCT3/4, Nestin, NANOG, CD44 and CD24 as stem cell markers in canine prostate cancer

The cancer cell population is heterogeneous, and cancer stem cells (CSCs) are important for tumor growth and maintenance. The CSC population is associated with different neoplastic characteristics, such as cell migration, resistance to apoptosis, radiation therapy and chemotherapy. To increase the knowledge of CSCs in canine prostate cancer (PC), we characterized CSC markers in canine PC tissues and tumorspheres. We performed immunohistochemistry of OCT3/4, Nestin, NANOG, CD44 and CD24 in 10 normal canine prostatic tissue samples, 10 prostatic hyperplastic (PH) tissue samples and 28 PC tissue samples. Then, we established two canine prostate cancer cell cultures and characterized the CSC profile of tumorspheres grown from these cultures. Normal and PH tissues were positive for Nestin, NANOG, CD44 and CD24 only in the basal cell layer. OCT3/4 was expressed in the luminal cells of normal and PH tissues. There was no significant difference in Nestin expression among the prostatic tissues. However, we found higher expression of NANOG and CD44 in canine PC tissues than that in normal and PH tissues. Tumorspheres from canine prostate cancer cells express OCT3/4, Nestin, NANOG and CD44, indicating that these markers may be potential cancer stem cell markers in canine PC. The results obtained can be useful to better characterize the stem cell population in canine prostatic cancer and to guide future studies in comparative oncology.

Evaluation of Hemostatic Parameters in Tumor-Bearing Dogs

Background: Hemostatic alterations are commonly detected in canine cancer patients. However, few studies have described hemostatic dysfunction in dogs with different tumor subtypes. In Veterinary Medicine, the state of hypercoagulability is hardly diagnosed alive, since laboratory exams for evaluate hemostatic function are not always requested. Due to importance of homeostatic disorders in cancer patients, this study aimed to evaluate hemostatic alterations such as platelet count, activated partial thromboplastin time (aPTT), prothrombin time (PT) and fibrinogen in tumor-bearing dogs.Materials, Methods & Results: From the 55 dogs evaluated, 30 had mammary carcinoma, 6 visceral hemangiosarcoma, 9 high-grade cutaneous mast cell tumor and 10 multicentric lymphoma. The results were compared to a control group composed by 10 Beagle dogs. Thrombocytosis was observed in 26.6% (8/30) of mammary carcinoma group and thrombocytopenia in 10% (3/30). The patients with hemangiosarcoma and mast cell tumor did not reveal thrombocytosis, however, thrombocytopenia was present in 16.6% (1/6) and 33% (3/9), respectively. Three dogs with multicentric lymphoma showed thrombocytopenia and other three showed thrombocytosis. From patients with thrombocytosis, one was classified as severe thrombocytosis (1077 x 10³/µL). Therefore, there were no statistically significant associations between neoplasia group with control group (P > 0.05). Regarding the aPTT and PT evaluation, mammary carcinoma (P = 0.0005), hemangiosarcoma (P = 0.033) and mast cell tumor (P = 0.012) patients showed statistical difference for aPTT, while the evaluation for PT was not significant (P > 0.05). We grouped all patients as a “tumor group” and compared to the control group. It was possible to observe increased aPTT and PT in 89% (49/55) and 50.90% (28/55) respectively, in tumor group compared to normal. A total of 47.27% (n = 26) of the patients with tumors presented increased aPTT and PT concomitantly. In the present study, 14.54% of the patients presented elevated levels of fibrinogen associated with increased aPTT. However, only the mast cell tumor group was statistically significant (P = 0.043).Discussion: Hemostatic alterations can be found in dogs with cancer and when these alterations occurs, can be directly associated with tumoral non-invasive actions called as paraneoplastic syndrome. However, the hemostatic paraneoplastic syndrome is poorly reported in veterinary medicine, with limited number of papers describing this condition. Our results indicated that the presence of thrombocytosis in patients with tumors could be related with the production of granulocytemacrophage colony stimulating factors (GM-CSF) and IL-6 by tumor cells. A total of 26 patients with tumors presented increased aPTT and PT concomitantly, confirming that hemostatic dysfunction is a common alteration in dogs with neoplasia. However, despite alterations in coagulation parameters, there were no clinical manifestations of bleeding such as petechial or bruising in these patients. The increased fibrinogen and aPTT can be caused by a systemic inflammatory reaction mediated by pro-inflammatory cytokines produced by tumors cells. Based on that, 14.54% of the animals presented elevated levels of fibrinogen associated with elevated aPTT suggesting that these patients are associated with systemic inflammation and tumor progression. This study suggested that bearing-tumors patients shows important hemostatic dysfunctions, elucidating the clinical importance of these results in veterinary medicine.

An immunohistochemical study of T and B lymphocyte density in prostatic hyperplasia and prostate carcinoma in dogs

The aim of this study was to characterise T and B lymphocyte density in 6 normal prostates, 15 benign prostatic hyperplasia (BPH) and 24 prostate carcinomas (PCs) in dogs by immunohistochemistry. Results revealed a statistically significant increase of T and B cells in PC compared to normal specimens and BPH. Regarding PC histological variants, lower number of CD3⁺ and CD79⁺ lymphocytes were observed in the most undifferentiated (solid) type. CD3⁺ cell density was positively correlated with survival time. These results may help in understanding the immunological mechanisms regulating BPH and PC development and progression, as well as providing background data for future immunotherapeutic trials.

Hydroxyurea-induced onychomadesis in a dog with chronic myeloid leukemia: A case report

A 12-year-old Rottweiler dog was presented with a history of prostration, weight loss and hyporexia for six months. Based on complete blood tests (hematological and biochemical analyses), bone marrow examination and imaging analysis, a diagnosis of chronic myeloid leukemia was made. Treatment with hydroxyurea at a dosage of 18 mg/kg twice daily was not effective in controlling the high count of white blood cells. Furthermore, after 35 days of hydroxyurea treatment, the animal developed onycholysis, with sloughing of the claws of the left pelvic and left thoracic limbs and exposure of the distal phalanx. Interruption of the medication was implemented, with clinical healing of the ungual lesions observed three months after initiation of the drug. White blood cells returned to normal after using cyclophosphamide. Currently, the animal is in complete remission, having a disease-free interval of 575 days without chemotherapy. To the authors' knowledge, this is the first report of hydroxyurea-induced onycholysis within a short-term period in a dog diagnosed with chronic myeloid leukemia.

Immunohistochemical panel to characterize canine prostate carcinomas according to aberrant p63 expression

An unusual variant of prostate adenocarcinoma (PC) expressing nuclear p63 in secretory cells instead of the typical basal expression has been reported in men. Nevertheless, the biological behavior and clinical significance of this phenomenon is unknown. In dogs, this unusual PC subtype has not been described. In this study, p63 immunoexpression was investigated in 90 canine PCs and 20 normal prostate tissues (NT). The p63 expression pattern in luminal or basal cells was confirmed in a selected group of 26 PCs and 20 NT by immunohistochemistry and/or Western blotting assays. Eleven canine PC samples aberrantly expressing p63 (p63+) in secretory cells were compared with 15 p63 negative (p63-) cases in the context of several molecular markers (high molecular weight cytokeratin-HMWC, CK8/18, CK5, AR, PSA, chromogranin, NKX3.1, PTEN, AKT and C-MYC). P63+ samples were positive for CK5, HMWC and CK8/18 and negative for PSA, NKX3.1, PTEN and chromogranin. Five p63+ PCs were negative for AR, and the remaining six samples had low AR expression. In contrast, p63- PC showed AR and PSA positive expression in all 15 samples. Only five p63- PCs were positive for CK5. Both p63+ and p63- PC samples showed higher cytoplasmic AKT expression and nuclear C-MYC staining in comparison with normal tissues. Metastatic (N = 12) and non-metastatic (N = 14) PCs showed similar immunoexpression for all markers tested. In contrast to human PC, canine PC aberrantly expressing p63 showed higher expression levels of HMWC and CK5 and lower levels of NKX3.1. Canine p63+ PC is a very rare PC group showing a distinct phenotype compared to typical canine PC, including AR and PSA negative expression. Although in a limited number of cases, p63 expression was not associated with metastasis in canine PC, and cytoplasmic p63 expression was observed in animals with shorter survival time, similar to human PC cases.

Evaluation of NKX3.1 and C-MYC expression in canine prostatic cancer

NKX3.1/C-MYC cross-regulation has been reported in the normal human prostate, and loss of NKX3.1 and gain of C-MYC seem to be important events in prostate cancer development and progression. The dog can be an interesting model for human prostatic disease, and yet only one previous research study has shown deregulation of NKX3.1 and MYC in the canine prostate. To address the expression of NKX3.1 and C-MYC in different canine prostatic lesions, this study verified the gene and protein expression of NKX3.1 and C-MYC in normal canine prostatic tissues. We identified a 26 kDa band that corresponded to the NKX3.1 protein, while C-MYC showed a 50 kDa band on Western blotting analysis of all prostatic tissues. We observed that NKX3.1 protein and transcript were down-regulated in prostate cancer (PC) samples compared with non-neoplastic samples. We also observed that C-MYC protein was overexpressed in PC samples compared with normal (P = .001) and proliferative inflammatory atrophy (PIA) samples (P = .003). We found a positive correlation between NKX3.1 and C-MYC protein expression in normal and PIA samples. Interestingly, a negative correlation (NKX3.1 downregulation and MYC overexpression) was observed between NKX3.1 and MYC transcripts in PC. Thus, samples with higher C-MYC expression also exhibited higher NKX3.1 expression, which indicates the regulation of C-MYC by NKX3.1 protein. As in humans, these two genes and proteins were found to be related to canine prostate cancer. However, in contrast from what is observed in humans, in canine PC samples, the downregulation of NKX3.1 cannot be explained by DNA hypermethylation.

Investigation of c-KIT and Ki67 expression in normal, preneoplastic and neoplastic canine prostate

BACKGROUND

c-KIT expression has been related to bone metastasis in human prostate cancer, but whether c-KIT expression can be similarly classified in canine prostatic tissue is unknown. This study assessed c-KIT and Ki67 expression in canine prostate cancer (PC). c-KIT gene and protein expression and Ki67 expression were evaluated in forty-four canine prostatic tissues by immunohistochemistry, RT-qPCR and western blot. Additionally, we have investigated c-KIT protein expression by immunoblotting in two primary canine prostate cancer cell lines.

RESULTS

Eleven normal prostates, 12 proliferative inflammatory atrophy (PIA) prostates, 18 PC, 3 metastatic lesions and two prostate cancer cell cultures (PC1 and PC2) were analysed. The prostatic tissue exhibited varying degrees of membranous, cytoplasmic or membranous/cytoplasmic c-KIT staining. Four normal prostates, 4 PIA and 5 prostatic carcinomas showed positive c-KIT expression. No c-KIT immunoexpression was observed in metastases. Canine prostate cancer and PIA samples contained a higher number of Ki67-positive cells compared to normal samples. The median relative quantification (RQ) for c-KIT expression in normal, PIA and prostate cancer and metastatic samples were 0.6 (0.1-2.5), 0.7 (0.09-2.1), 0.7 (0.09-5.1) and 0.1 (0.07-0.6), respectively. A positive correlation between the number of Ki67-positive cells and c-KIT transcript levels was observed in prostate cancer samples. In the cell line, PC1 was negative for c-KIT protein expression, while PC2 was weakly positive.

CONCLUSION

The present study identified a strong correlation between c-KIT expression and proliferative index, suggesting that c-KIT may influence cell proliferation. Therefore, c-KIT heterogeneous protein expression among the samples (five positive and thirteen negative prostate cancer samples) indicates a personalized approach for canine prostate cancer.

Histopathological and Immunohistochemical Evaluation of Primary Muscular Peripheral T Cell Lymphoma in a Dog

Background: Canine lymphoma is the most common hematopoietic neoplasm in dogs and reveals divergent biological behaviors correlated to histopathological subtype, the immunophenotypic (T or B) and tumor stage. The multi-centric form is the most common presentation for canine lymphoma, followed by gastrointestinal and cutaneous forms. Miscellaneous forms of canine lymphoma (nasal, osseous, central nervous system and muscle) represent less than 1% of all cases. This report describes the clinical, macroscopic, histopathological and immunohistochemical findings detected in a dog with a primary muscular lymphoma.Case: The subject was referred to the Emergency and Critical Care Service at the Veterinary Hospital with a history of claudication in the left pelvic limb, severe dehydration, hypovolemia, vomiting and diarrhea caused by gastroenteritis associated with the use of phenylbutazone. After death, the post-mortem examination revealed ulcerative gastritis in the gastrointestinal tract (GIT). Histopathological examination of the GIT specimens, mesenteric lymph nodes, and the left popliteal lymph node revealed no neoplastic alterations. Histological examination of semitendinosus muscle revealed proliferation of cells with round or oval nucleus, an evident pleomorphic nucleolus and scanty, eosinophilic cytoplasm. There were five to six mitosis per each 400x field. These cells infiltrated through the muscle fibers. The muscle fibers displayed marked eosinophilic sarcoplasm, loss of striations and fragmentation (degeneration). Immunohistochemical staining revealed negative reaction for CD79a and positive for CD45 and CD3.Discussion: The primary muscle lymphoma it is very rare disease and patients commonly have clinical signs related with muscle location. Our description of muscular primary lymphoma affecting the semitendinosus muscle emphasize that it must be included as a differential diagnosis for dogs with unilateral lameness, inflammatory processes, and other malignancies. In this case, the patient showed an ulcerative gastroenteritis associated with the inappropriate use of phenylbutazone. The patient death was associated with a septicemia due to several ulcers in the gastrointestinal tract. We excluded any regional lymph node involvement and secondary muscular infiltration with post-mortem and histopathological examination. The gross evaluation of the left hind limb demonstrated only muscular involvement (semitendinosus muscle) without infiltration in the adjacent structures, and the histopathology revealed no alteration in the regional lymph node. The immunohistochemical evaluation showed negative staining to CD79a, a high number of positive cells to Ki67 and positive staining to CD45 and CD3. In normal lymph nodes, it was possible to note CD79 diffuse expression in germinal centers in lymphoid follicles and few positive B-lymphocytes in medullary region. Diffuse CD3 expression was found in cortex region by normal Tlymphocytes. There was no histological alterations in sublumbar and popliteal lymph nodes. This immunohistochemical and histological patterns revealed a Peripheral T Cell lymphoma with a high proliferative index. The previous report of primary muscular lymphoma showed a T cell lymphoma with a high proliferative index similar to our findings. Based on macroscopic, histopathological, and immunohistochemical findings it was concluded that the patient had a primary muscular Peripheral T Cell lymphoma.

Alterations in PTEN, MDM2, TP53 and AR protein and gene expression are associated with canine prostate carcinogenesis

The PTEN, AR, MDM2 and p53 protein network plays a central role in the development of many human cancers, thus eliciting the development of targeted cancer therapeutics. Dogs spontaneously develop tumours, and they are considered a good model for comparative oncology initiatives. Due to the limited information on these proteins in canine tumours, this study aimed to investigate gene and protein alterations in PTEN, AR, MDM2 and p53 in canine prostate cancer (PC). Protein expression was evaluated by immunohistochemistry (15 normal, 22 proliferative inflammatory atrophy (PIA) and 19 PC samples) and Western blotting (2 normal prostate tissue, 2 BPH, 2 PIA samples and 2 PC samples) and gene expression by RT-qPCR (10 normal, 10 PIA and 15 PC samples) of formalin-fixed tissue. We identified nuclear and cytoplasmic expression of PTEN and p53 in all samples, with only nuclear staining found for MDM2 and AR. Our results revealed high expression of MDM2 in PC and PIA samples compared to normal samples, whereas PTEN, P53 and AR expression was down-regulated in PC compared to normal tissue. All tumour samples (n=19) showed loss of nuclear PTEN expression, and all cancer mimickers showed positive nuclear staining. Therefore, nuclear PTEN staining could be a good diagnostic marker for differentiating between malignant lesions and mimickers. Canine prostate carcinogenesis involves increased expression of MDM2 in association with decreased expression of PTEN, p53 and AR, such as occurs in hormone refractory PC in men. Thus, dogs may be an important model for studying advanced stage PC.

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.