BACKGROUND: Feline injection-site sarcoma (FISS), an aggressive iatrogenic subcutaneous malignancy, is challenging to manage clinically and little is known about the molecular basis of its pathogenesis. Tumor transcriptome profiling has proved valuable for gaining insights into the molecular basis of cancers and for identifying new therapeutic targets. Here, we report the first study of the FISS transcriptome and the first cross-species comparison of the FISS transcriptome with those of anatomically similar soft-tissue sarcomas in dogs and humans.
METHODS: Using high-throughput short-read paired-end sequencing, we comparatively profiled FISS tumors vs. normal tissue samples as well as cultured FISS-derived cell lines vs. skin-derived fibroblasts. We analyzed the mRNA-seq data to compare cancer/normal gene expression level, identify biological processes and molecular pathways that are associated with the pathogenesis of FISS, and identify multimegabase genomic regions of potential somatic copy number alteration (SCNA) in FISS. We additionally conducted cross-species analyses to compare the transcriptome of FISS to those of soft-tissue sarcomas in dogs and humans, at the level of cancer/normal gene expression ratios.
RESULTS: We found: (1) substantial differential expression biases in feline orthologs of human oncogenes and tumor suppressor genes suggesting conserved functions in FISS; (2) a genomic region with recurrent SCNA in human sarcomas that is syntenic to a feline genomic region of probable SCNA in FISS; and (3) significant overlap of the pattern of transcriptional alterations in FISS with the patterns of transcriptional alterations in soft-tissue sarcomas in humans and in dogs. We demonstrated that a protein, BarH-like homeobox 1 (BARX1), has increased expression in FISS cells at the protein level. We identified 11 drugs and four target proteins as potential new therapies for FISS, and validated that one of them (GSK-1059615) inhibits growth of FISS-derived cells in vitro.
CONCLUSIONS: (1) Window-based analysis of mRNA-seq data can uncover SCNAs. (2) The transcriptome of FISS-derived cells is highly consistent with that of FISS tumors. (3) FISS is highly similar to soft-tissue sarcomas in dogs and humans, at the level of gene expression. This work underscores the potential utility of comparative oncology in improving understanding and treatment of FISS.

Lymphoma is one of the most common neoplasms in dogs and it is one of the top five causes of cancer-related deaths, similar to human lymphoma. Companion animal epidemiological studies define dogs as sentinels of potential risk factors for human health, mainly due to shared environments, shorter disease latencies, and spontaneous disease. The aims of this study were to describe human and canine epidemiologic features of non-Hodgkin's lymphoma (NHL) and their similarities, and to investigate a possible geographical association in the incidence risks in the Greater Porto area, in north-western Portugal. The postal codes of human NHL patients diagnosed between 2005 and 2010 residing in the Greater Porto, Portugal, were obtained from North and Central Region Cancer Registries of Portugal. Available data from dogs diagnosed with lymphoma between 2005 and 2016 from several veterinary centres were also collected. Descriptive epidemiology, mapping cases, and age-standardised risks of NHL incidence (ASR) were determined for both species. The results showed a higher risk (P<0.05) of NHL in men (ASR men: 18.1 cases/100,000 inhabitants; women: 14.2 cases/100,000 inhabitants) and in male dogs (ASR males: 82 cases/100,000 dogs; females: 70 cases/100,000 dogs). The geographical distribution of human and canine ASR was well correlated (r=0.664, P<0.05), with the highest values for human and canine ASR detected in the same urban municipalities of the Greater Porto: Porto, Matosinhos and Maia. These findings suggest the existence of exposure similarities, supporting the relevance of cancer surveillance in pet animals as efficient tools to predict health hazards for humans.

We previously showed that the promoter region of the human epidermal growth factor receptor (hEGFR) gene elicits high transduction efficiency, with transgene expression restricted to canine breast tumor cells. However, it was unclear whether this promoter induces tumor cell-specific transgene expression in canine urothelial carcinoma cells. Furthermore, compared with studies in human cancer cells, the utility of the telomerase reverse transcriptase (TERT) gene promoter for therapeutic transgene expression in canine cancer cells has not been evaluated thus far. Here, we compared the activity of these promoters in canine mammary tumor and urothelial carcinoma cells. Our results showed that compared with the TERT promoter, the hEGFR promoter was more useful as a tumor-specific promoter to induce efficient transgene expression in canine tumor cells.

Mucosal melanoma is a rare and poorly characterized subtype of human melanoma. Here we perform a cross-species analysis by sequencing tumor-germline pairs from 46 primary human muscosal, 65 primary canine oral and 28 primary equine melanoma cases from mucosal sites. Analysis of these data reveals recurrently mutated driver genes shared between species such as NRAS, FAT4, PTPRJ, TP53 and PTEN, and pathogenic germline alleles of BRCA1, BRCA2 and TP53. We identify a UV mutation signature in a small number of samples, including human cases from the lip and nasal mucosa. A cross-species comparative analysis of recurrent copy number alterations identifies several candidate drivers including MDM2, B2M, KNSTRN and BUB1B. Comparison of somatic mutations in recurrences and metastases to those in the primary tumor suggests pervasive intra-tumor heterogeneity. Collectively, these studies suggest a convergence of some genetic changes in mucosal melanomas between species but also distinctly different paths to tumorigenesis.

Osteosarcoma (OSA) represents the most common primary bone tumor in humans and pet dogs. Little progress has been made with regard to viable treatment options in the past three decades and patients presenting with metastatic disease continue to have a poor prognosis. Recent mouse studies have suggested that microRNA-34a (miR-34a) may have anti-tumor activities in human OSA models. Due to the conservation of microRNA across species, we hypothesized that a bioengineered miR-34a prodrug (tRNA/miR-34a) would have similar effects in canine OSA, providing a valuable preclinical model for development of this therapeutic modality. Using a panel of canine OSA cell lines, we found that tRNA/miR-34a reduced viability, clonogenic growth, and migration and invasion while increasing tumor cell apoptosis. Furthermore, canine OSA cells successfully process the tRNA/miR-34a into mature miR-34a which reduces expression of target proteins such as platelet derived growth factor receptor alpha (PDGFRα), Notch1 and vascular endothelial growth factor (VEGF). Additionally, our subcutaneous OSA xenograft model demonstrated in vivo tumor growth delay, increased necrosis and apoptosis by tRNA/miR-34a, and decreased cellular proliferation ability. Taken together, these data support that this novel microRNA-based therapy may possess clinical utility in a spontaneously-occurring large animal model of OSA, which can then serve to inform the clinical development of this therapy for human OSA patients.

BACKGROUND: Metastatic melanoma is one of the most aggressive forms of cancer in humans. Among its types, mucosal melanomas represent one of the most highly metastatic and aggressive forms, with a very poor prognosis. Because they are rare in Caucasian individuals, unlike cutaneous melanomas, there has been fewer epidemiological, clinical and genetic evaluation of mucosal melanomas. Moreover, the lack of predictive models fully reproducing the pathogenesis and molecular alterations of mucosal melanoma makes its treatment challenging. Interestingly, dogs are frequently affected by melanomas of the oral cavity that are characterized, as their human counterparts, by focal infiltration, recurrence, and metastasis to regional lymph nodes, lungs and other organs. In dogs, some particular breeds are at high risk, suggesting a specific genetic background and strong genetic drivers. Altogether, the striking homologies in clinical presentation, histopathological features, and overall biology between human and canine mucosal melanomas make dogs invaluable natural models with which to investigate tumor development, including tumor ætiology, and develop tailored treatments.
METHODS: We developed and characterized two canine oral melanoma cell lines from tumors isolated from dog patients with distinct clinical profiles; with and without lung metastases. The cells were characterized using immunohistochemistry, pharmacology and genetic studies.
RESULTS: We have developed and immunohistochemically, genetically, and pharmacologically characterized. Two cell lines (Ocr_OCMM1X & Ocr_OCMM2X) were produced through mouse xenografts originating from two clinically contrasting melanomas of the oral cavity. Their exhaustive characterization showed two distinct biological and genetic profiles that are potentially linked to the stage of malignancy at the time of diagnosis and sample collection of each melanoma case. These cell lines thus constitute relevant tools with which to perform genetic and drug screening analyses for a better understanding of mucosal melanomas in dogs and humans.
CONCLUSIONS: The aim of this study was to establish and characterize xenograft-derived canine melanoma cell lines with different morphologies, genetic features and pharmacological sensitivities that constitute good predictive models for comparative oncology. These cell lines are relevant tools to advance the use of canine mucosal melanomas as natural models for the benefit of both veterinary and human medicine.

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.

The aim of this study was to evaluate the safety and efficacy of the combination of electrochemotherapy (ECT) with bleomycin and gene electrotransfer (GET) of plasmid encoding canine interleukin 12 (IL-12) for the treatment of canine oral malignant melanoma (OMM). Our focus was to determine the effect of the treatment on achieving local tumor control and stimulation of an antitumor immune response. Nine dogs with histologically confirmed OMM stage I to III were included in a prospective, non-randomized study. The dogs were treated with a combination of cytoreductive surgery, ECT and IL-12 GET, which was repeated up to five times, depending on the clinical response to the treatment, evaluated according to the follow-up protocol (7, 14 and 28 days after, the last treatment). One month after treatment, the objective response (OR) rate was 67% (6/9). Median survival time (MST) was 6 months and, even though the disease progressed in 8/9 patients at the end of the observation period (2 to 22 months), four animals were euthanized due to tumor-unrelated reasons. In addition, we observed a decline in the percentage of regulatory T cells (T

Combretastatin A-4 phosphate (CA4P) induces tumor necrosis by selectively inhibiting tumor blood flow. However, the detailed mechanisms by which CA4P selectively disrupts tumor blood vessels are not well understood. Our previous study indicated that the selective blocking effect of CA4P might be related to a vascular endothelial cadherin (VE-cadherin) dysfunction in the tumor vasculature. In this study, we evaluated the vascular disrupting effect of CA4P on canine osteosarcomas xenografted into mice, focusing on VE-cadherin. Even though 30 mg/kg CA4P only partially inhibited blood flow in the xenografted tumor, a combination of an anti-VE-cadherin neutralizing antibody and 30 mg/kg CA4P inhibited most of the tumor blood flow. In addition, the combination of antibody and drug significantly inhibited tumor growth compared to the control. These results strongly suggested a relationship between the expression of VE-cadherin in tumor blood vessels and the selective blocking mechanisms of CA4P.

Podoplanin (PDPN), a type I transmembrane sialoglycoprotein, is expressed in normal tissues, including lymphatic endothelial cells, pulmonary type I alveolar cells, and renal podocytes. The overexpression of PDPN in cancers is associated with hematogenous metastasis by interactions with the C-type lectin-like receptor 2 (CLEC-2). We have previously reported the development of a mouse monoclonal antibody (mAb) clone, PMab-38 (IgG

BACKGROUND/AIM: The aim of the present study was to evaluate a multimodal approach for the treatment of canine malignant mammary gland neoplasms, including surgery, chemotherapy, thalidomide, and metronomic chemotherapy (MC).
MATERIALS AND METHODS: Fifty-eight female dogs were submitted to four different treatments: surgery; surgery with chemotherapy; surgery with chemotherapy and thalidomide; and surgery with chemotherapy and metronomic chemotherapy and overall survival was evaluated.
RESULTS: No statistical difference was found in the proliferative index and microvessel density of primary neoplasms and distant metastases following thalidomide treatment. Diffuse intense inflammatory infiltrate was predominant in primary tumors and diffuse moderate inflammatory infiltrate in metastatic lesions. No statistically significant difference was observed in median survival time (MST) between treatment groups when including all clinical stages (p=0.3177). However, animals diagnosed with distant metastasis treated with surgery and chemotherapy associated with thalidomide or MC presented longer MST when compared to animals treated only with surgery or surgery and chemotherapy (p<0.0001).
CONCLUSION: The proposed multimodal therapy protocols including antiangiogenic and immunomodulatory therapies demonstrated a clinical benefit for patients in advanced clinical stages.

We developed a new transcutaneous method for breast cancer detection with dogs: 2 dogs were trained to sniff skin secretion samples on compresses that had been worn overnight by women on their breast, and to recognize a breast cancer sample among 4 samples. During the test, the dogs recognized 90.3% of skin secretion breast cancer samples. This proof-of-concept study opens new avenues for the development of a reliable cancer diagnostic tool integrating olfactory abilities of dogs.

BACKGROUND: Current animal models of glioma are limited to small animal models, which are less predictive of treatment of human disease. Canines often develop gliomas de novo, but the natural history of the disease is not well described.
OBJECTIVE: We provide data for naturally occurring canine gliomas; evaluating medical and surgical therapies.
METHODS: We reviewed medical records of pet dogs with a presumptive diagnosis of glioma from MRI imaging that underwent surgery as part of the Canine Brain Tumor Clinical Trials Program. Breed, age, sex, median progression-free, and overall survival times and cause of death were recorded for multivariate analysis.
RESULTS: Ninety five dogs (56 male; mean age = 8.3 years) were included, but nine were excluded as final pathology was non-neoplastic. Gross total resection was reported in 81 cases based on postoperative MRI. Seventy had high-grade tumors (grade III or IV). Eighty three dogs presented with seizures, being the most common presenting clinical sign. Median survival after surgery was 723 days (95% CI 343-1103) for grade II tumors, 301 days (197-404) for grade III and 200 days (126-274) for grade IV (p = .009 Kaplan-Meier survival analysis; Log Rank test). Age (cox regression, p = .14) or sex (Kaplan-Meier test, p = .22) did not predict survival.
CONCLUSIONS: This study establishes normative data for a model exploiting dogs with naturally occurring glioma, which can be used to test novel therapies prior to translation to human trials. Further work will focus on the effects of different therapies, including chemotherapy, radiation therapy, and immunotherapy.

The neoplastic mass developed in the left flank of a Border Collie dog. The tumor was resected surgically and evaluated histologically and immunohistochemically. Histologically a moderate number of spindle cells were proliferated with staghorn, placentoid, and myxoid growth patterns and a lack of perivascular whirling. Immunohistochemically, the tumor cells were positive to vimentin, laminin, S-100 protein, CD34 and CD117 antibodies. They were negative to cytokeratin AE1/3, desmin, α-SMA and calponin antibodies. Endothelial cells of the staghorn channels were positive for vWF antibody. The present case was diagnosed as spindle cell tumor, but it was similar to human classical hemangiopericytoma (HEP) and canine HEP classified by Avallon and others.

The objective of this study was to investigate a possible mechanism of action of metronomic chlorambucil on glioma by studying the in vitro cytotoxicity and anti-angiogenic effects on glioma and endothelial cells, respectively. The in vitro LD50 and IC50 of chlorambucil were determined using human SF767 and U87-MG glioma cell lines, human microvascular endothelial cells (HMVECs) and human endothelial colony forming cells (ECFCs). Results were analyzed in the context of chlorambucil concentrations measured in the plasma of tumor-bearing dogs receiving 4 mg m-2 metronomic chlorambucil. The LD50 and IC50 of chlorambucil were 270 μM and 114 μM for SF767, and 390 μM and 96 μM for U87-MG, respectively. The IC50 of chlorambucil was 0.53 μM and 145 μM for the HMVECs and ECFCs, respectively. In pharmacokinetic studies, the mean plasma Cmax of chlorambucil was 0.06 μM. Results suggest that metronomic chlorambucil in dogs does not achieve plasma concentrations high enough to cause direct cytotoxic or growth inhibitory effects on either glioma or endothelial cells.

EgKI-1, a member of the Kunitz type protease inhibitor family, is highly expressed by the oncosphere of the canine tapeworm Echinococcus granulosus, the stage that is infectious to humans and ungulates, giving rise to a hydatid cyst localized to the liver and other organs. Larval protoscoleces, which develop within the hydatid cyst, have been shown to possess anti-cancer properties, although the precise molecules involved have not been identified. We show that recombinant EgKI-1 inhibits the growth and migration of a range of human cancers including breast, melanoma and cervical cancer cell lines in a dose-dependent manner in vitro without affecting normal cell growth. Furthermore, EgKI-1 treatment arrested the cancer cell growth by disrupting the cell cycle and induced apoptosis of cancer cells in vitro. An in vivo model of triple negative breast cancer (MDA-MB-231) in BALB/c nude mice showed significant tumor growth reduction in EgKI-1-treated mice compared with controls. These findings indicate that EgKI-1 shows promise for future development as an anti-cancer therapeutic.

Immunotherapeutic strategies have shown promise for the treatment of canine osteosarcoma (cOSA). Very little is known about the immune microenvironment within cOSA, however, limiting our ability to identify potential immune targets and biomarkers of therapeutic response. We therefore prospectively assessed the disease-free interval (DFI) and overall survival time (ST) of 30 dogs with cOSA treated with amputation and six doses of adjuvant carboplatin. We then quantified lymphocytic (CD3+, FOXP3+) and macrophage (CD204+) infiltrates within the primary tumours of this cohort using immunohistochemistry, and evaluated their association with outcome. Overall, the median DFI and ST were 392 and 455 days, respectively. The median number of CD3+ and FOXP3+ infiltrates were 45.8 cells/mm

In humans, advanced mast cell (MC) neoplasms are rare malignancies with a poor prognosis. Only a few preclinical models are available, and current treatment options are limited. In dogs, MC neoplasms are the most frequent malignant skin tumours. Unlike low-grade MC neoplasms, high-grade MC disorders usually have a poor prognosis with short survival. In both species, neoplastic MCs display activating KIT mutations, which are considered to contribute to disease evolution. Therefore, tyrosine kinase inhibitors against KIT have been developed. Unfortunately, clinical responses are unpredictable and often transient, which remains a clinical challenge in both species. Therefore, current efforts focus on the development of new improved treatment strategies. The field of comparative oncology may assist in these efforts and accelerate human and canine research regarding diagnosis, prognostication, and novel therapies. In this article, we review the current status of comparative oncology approaches and perspectives in the field of MC neoplasms.

OBJECTIVE: To compare ventral cervical and bilateral lateral incisions for extirpation of mandibular and medial retropharyngeal lymph nodes in dogs.
STUDY DESIGN: Prospective randomized, crossover controlled cadaver trial.
SAMPLE POPULATION: Eight veterinarians with advanced surgical training.
METHODS: Study participants were randomized to perform both techniques on paired cadavers. Time to extirpation of the first and last lymph node, length of incisions, and complications were recorded for both techniques. Participants were asked to rate satisfaction with their ability to identify local anatomy and lymph nodes as well as overall preferred technique by using a 10-point numerical rating scale.
RESULTS: The total length of skin incised for the bilateral lateral approach exceeded that of the ventral cervical approach by 52.1 mm (mean, P < .001). The surgical time for removal of all 4 lymph nodes did not differ between the 2 approaches. The bilateral lateral approach was preferred by 62.5% (5/8) of participants for visualization of mandibular lymph nodes, and the ventral cervical approach was preferred by 87.5% (7/8) of participants for visualization of local anatomy. Overall, 62.5% (5/8) preferred the ventral cervical approach and 37.5% (3/8) preferred the bilateral lateral approach.
CONCLUSION: The ventral cervical approach was preferred by participants for its perceived superior visualization of local anatomy and access to lymph nodes for removal. This approach also resulted in an overall shorter incision length.
CLINICAL SIGNIFICANCE: A ventral cervical or bilateral lateral approach allows successful removal of the medial mandibular and retropharyngeal lymph nodes in dogs, and surgical approach may be selected according to individual preference.

BACKGROUND: Breast (mammary) cancers in human (BC) and canine (CMT) patients share clinical, pathological, and molecular similarities that suggest dogs may be a useful translational model. Many cancers, including BC, shed exosomes that contain microRNAs (miRs) into the microenvironment and circulation, and these may represent biomarkers of metastasis and tumor phenotype.
METHODS: Three normal canine mammary epithelial cell (CMEC) cultures and 5 CMT cell lines were grown in serum-free media. Exosomes were isolated from culture media by ultracentrifugation then profiled by transmission electron microscopy, dynamic light scattering, and Western blot. Exosomal small RNA was deep-sequenced on an Illumina HiSeq2500 sequencer and validated by qRT-PCR. In silico bioinformatic analysis was carried out to determine microRNA gene and pathway targets.
RESULTS: CMEC and CMT cell lines shed round, "cup-shaped" exosomes approximately 150-200 nm, and were immunopositive for exosomal marker CD9. Deep-sequencing averaged ~ 15 million reads/sample. Three hundred thirty-eight unique miRs were detected, with 145 having > ±1.5-fold difference between one or more CMT and CMEC samples. Gene ontology analysis revealed that the upregulated miRs in this exosomal population regulate a number of relevant oncogenic networks. Several miRNAs including miR-18a, miR-19a and miR-181a were predicted in silico to target the canine estrogen receptor (ESR1α).
CONCLUSIONS: CMEC and CMT cells shed exosomes in vitro that contain differentially expressed miRs. CMT exosomal RNA expresses a limited number of miRs that are up-regulated relative to CMEC, and these are predicted to target biologically relevant hormone receptors and oncogenic pathways. These results may inform future studies of circulating exosomes and the utility of miRs as biomarkers of breast cancer in women and dogs.

There is growing evidence that molecular subtypes (e.g. luminal and basal subtypes) affect the prognosis and treatment response in patients with muscle invasive urinary bladder cancer (invasive urothelial carcinoma, iUC). Modeling these subtypes in pre-clinical animal studies is essential, but it is challenging to produce these subtypes, along with other critical host and tumor features, in experimentally-induced animal models. This study was conducted to determine if luminal and basal molecular subtypes are present in naturally-occurring canine iUC, a cancer that mimics the human condition in other key aspects. RNA sequencing was performed on 29 canine treatment naive iUC tissue samples and on four normal canine bladder mucosal samples. Data were aligned to CanFam 3.1, and differentially expressed genes were identified. Unsupervised hierarchical clustering of these genes revealed two distinct groups (n = 13, n = 16). When genes that distinguish basal and luminal subtypes in human cancer (n = 2015) were used to probe genes differentially expressed between normal canine bladder and iUC, 829 enriched signature genes were identified. Unsupervised hierarchical clustering of these genes revealed two distinct groups comprised of 18 luminal subtype tumors and 11 basal subtype tumors. The enriched genes included MMP9, SERPINE2, CAV1, KRT14, and RASA3 in basal tumors, and PPARG, LY6E, CTSE, CDK3, and TBX2 in luminal tumors. In supervised clustering, additional genes of importance in human iUC were identified in canine iUC associated with claudin-low and infiltrated tumors. A smaller panel of genes (n = 60) was identified that distinguished canine luminal and basal iUC with overall 93.1% accuracy. Immune signature patterns similar to those in human iUC were also identified with the greatest enrichment of immune genes being in the basal subtype tumors. These findings provide additional compelling evidence that naturally-occurring canine iUC is a highly relevant and much needed model of human iUC for translational research.

High-frequency irreversible electroporation is a nonthermal method of tissue ablation that uses bursts of 0.5- to 2.0-microsecond bipolar electric pulses to permeabilize cell membranes and induce cell death. High-frequency irreversible electroporation has potential advantages for use in neurosurgery, including the ability to deliver pulses without inducing muscle contraction, inherent selectivity against malignant cells, and the capability of simultaneously opening the blood-brain barrier surrounding regions of ablation. Our objective was to determine whether high-frequency irreversible electroporation pulses capable of tumor ablation could be delivered to dogs with intracranial meningiomas. Three dogs with intracranial meningiomas were treated. Patient-specific treatment plans were generated using magnetic resonance imaging-based tissue segmentation, volumetric meshing, and finite element modeling. Following tumor biopsy, high-frequency irreversible electroporation pulses were stereotactically delivered in situ followed by tumor resection and morphologic and volumetric assessments of ablations. Clinical evaluations of treatment included pre- and posttreatment clinical, laboratory, and magnetic resonance imaging examinations and adverse event monitoring for 2 weeks posttreatment. High-frequency irreversible electroporation pulses were administered successfully in all patients. No adverse events directly attributable to high-frequency irreversible electroporation were observed. Individual ablations resulted in volumes of tumor necrosis ranging from 0.25 to 1.29 cm

BRCA1-associated protein-1 (BAP1) is a nuclear localized deubiquitylating enzyme that belongs to the ubiquitin c-terminal hydrolase subfamily. The encoded protein is highly homologous between man and dogs, suggesting a functional significance preserved by evolution. BAP1 has multiple properties, including tumour suppressor activity. Loss of BAP1 function is implicated in the oncogenesis of several types of cancers including uveal, mucosal and some cutaneous melanomas in humans, as well as in mesothelioma. In this study we investigate the significance of BAP1 in canine melanoma. Nuclear BAP1 protein was detected in five canine oral melanoma cell lines using an antibody commonly used for analysis of human tissues. BAP1 loss of function mutations often lead to loss of nuclear BAP1 (nBAP1) expression in humans; this is associated with a poorer prognosis in uveal and mucosal melanoma. Therefore, as a prelude to a study evaluating the prognostic significance of nBAP1 expression in dogs, immunohistochemistry (IHC) was used to assess cases of canine melanoma for nBAP1 expression. In 89 cases where tumour cells were identified by melan-A labelling, 100% of tumour cells were positive for nBAP1 expression, including eight uveal tract and 29 oral mucosal melanomas. This finding indicates that BAP1 IHC cannot be used as a prognostic marker in canine uveal and mucosal melanoma. Moreover, this observation suggests that either BAP1 has a different functional significance in canine melanoma or that loss of BAP1 function is achieved by a different route. This is a novel finding that warrants further investigation to determine the comparative biological relevance.

While extremely rare in humans, hemangiosarcoma (HSA) accounts for nearly 2% of canine neoplasia, and is characterized by both aggressive local growth/invasion and a high rate of metastasis. Both canine and human HSA exhibit sustained aberrant PI3K/Akt/mTOR pathway signaling. The purpose of this study was to examine the in vitro effects of a novel dual PI3K/mTOR inhibitor, VDC-597, in three canine HSA cell lines (DEN-, CIN-, and SB-HSA). VDC-597 suppressed activation of both Akt and 4eBP1 in canine HSA cells in a dose-dependent fashion, with an IC50 of approximately 0.3 uM, a concentration predicted to be clinically achievable based on preliminary early-phase canine and human studies. VDC-597 dose-dependently reduced proliferation, migration, and vascular endothelial growth factor production in HSA cells, while promoting tumor cell apoptosis. VDC-597 demonstrated additive antiproliferative effects when combined with doxorubicin. These results suggest that inhibitors of the PI3K/mTOR pathway may act against multiple components of the neoplastic process, including proliferation/apoptosis, chemosensitivity, migration, and angiogenesis, and justify the evaluation of PI3K/mTOR inhibitors in canine, and potentially human, HSA.

Osteosarcoma, a common malignancy in large dog breeds, typically metastasises from long bones to lungs and is usually fatal within 1 to 2 years of diagnosis. Better therapies are needed for canine patients and their human counterparts, a third of whom die within 5 years of diagnosis. We compared the in vitro sensitivity of canine osteosarcoma cells derived from 4 tumours to the currently used chemotherapy drugs doxorubicin and carboplatin, and 4 new anti-cancer drugs. Agents targeting histone deacetylases or PARP were ineffective. Two of the 4 cell lines were somewhat sensitive to the BH3-mimetic navitoclax. The proteasome inhibitor bortezomib potently induced caspase-dependent apoptosis, at concentrations substantially lower than levels detected in the bones and lungs of treated rodents. Co-treatment with bortezomib and either doxorubicin or carboplatin was more toxic to canine osteosarcoma cells than each agent alone. Newer proteasome inhibitors carfilzomib, ixazomib, oprozomib and delanzomib manifested similar activities to bortezomib. Human osteosarcoma cells were as sensitive to bortezomib as the canine cells, but slightly less sensitive to the newer drugs. Human osteoblasts were less sensitive to proteasome inhibition than osteosarcoma cells, but physiologically relevant concentrations were toxic. Such toxicity, if replicated in vivo, may impair bone growth and strength in adolescent human osteosarcoma patients, but may be tolerated by canine patients, which are usually diagnosed later in life. Proteasome inhibitors such as bortezomib may be useful for treating canine osteosarcoma, and ultimately may improve outcomes for human patients if their osteoblasts survive exposure in vivo, or if osteoblast toxicity can be managed.

Dogs were present in the Americas before the arrival of European colonists, but the origin and fate of these precontact dogs are largely unknown. We sequenced 71 mitochondrial and 7 nuclear genomes from ancient North American and Siberian dogs from time frames spanning ~9000 years. Our analysis indicates that American dogs were not derived from North American wolves. Instead, American dogs form a monophyletic lineage that likely originated in Siberia and dispersed into the Americas alongside people. After the arrival of Europeans, native American dogs almost completely disappeared, leaving a minimal genetic legacy in modern dog populations. The closest detectable extant lineage to precontact American dogs is the canine transmissible venereal tumor, a contagious cancer clone derived from an individual dog that lived up to 8000 years ago.

Osteosarcoma is a debilitating bone cancer that affects humans, especially children and adolescents. A homologous form of osteosarcoma spontaneously occurs in dogs, and its differential incidence observed across breeds allows for the investigation of tumor mutations in the context of multiple genetic backgrounds. Using whole-exome sequencing and dogs from three susceptible breeds (22 golden retrievers, 21 Rottweilers, and 23 greyhounds), we found that osteosarcoma tumors show a high frequency of somatic copy-number alterations (SCNA), affecting key oncogenes and tumor-suppressor genes. The across-breed results are similar to what has been observed for human osteosarcoma, but the disease frequency and somatic mutation counts vary in the three breeds. For all breeds, three mutational signatures (one of which has not been previously reported) and 11 significantly mutated genes were identified.

OBJECTIVE: To evaluate the feasibility of single-port retroperitoneoscopic adrenalectomy (SPRA) in dogs.
STUDY DESIGN: A pilot experimental study.
ANIMALS: Eight healthy beagle dogs.
METHODS: SPRA was performed on the left and right sides (4 dogs each). Resection of the adrenal gland was performed through a SILS port using a retroperitoneal approach. Operative time was defined from skin incision to the completion of skin suture. Postoperative pain was evaluated by using 3 pain scores. Integrity of the adrenal gland capsule was evaluated by histologic assessment.
RESULTS: Mean time taken to complete the SPRA was 44.1 minutes (range, 37-51) and was significantly longer on the right side than on the left side (P < .05). There were no complications intraoperatively or during 14 days of postoperative monitoring. The adrenal gland capsule was found to be injured in 3 of the 8 dogs by histologic assessment.
CONCLUSION: This is the first report of SPRA in the veterinary literature. With this technique it is possible to perform adrenalectomy with some risk of capsule penetration and with excellent visibility.
CLINICAL SIGNIFICANCE: This study suggests that SPRA is feasible and can be used to resect small adrenal tumors with minimal complications.

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.