The staging and treatment of multicentric high-grade lymphoma in dogs: a review of recent developments and future prospects

Prognostic value of peripheral blood and bone marrow infiltration assessed by flow cytometry in dogs with de novo nodal peripheral T-cell lymphoma receiving alkylating-rich chemotherapy

Peripheral T-cell lymphoma (PTCL) is highly aggressive in dogs and demonstrates a poor response to traditional chemotherapy. The aim of this retrospective study was to assess the prognostic significance of peripheral blood (PB) and bone marrow (BM) infiltration evaluated by flow cytometry (FC) in dogs with treatment-naïve and histologically confirmed PTCL. To be included, dogs had to undergo complete staging, including FC on lymph nodes, PB and BM samples. Additionally, dogs had to receive an alkylating-rich protocol and have a complete follow-up. Treatment response was evaluated based on RECIST criteria at each chemotherapy session, and the end-staging was conducted at the completion of treatment. Endpoints were time to progression (TTP) and lymphoma-specific survival (LSS). The relationship between TTP/LSS and the percentage of PB and BM infiltration, categorized as > 1%, > 3%, > 5%, > 10%, > 15% and > 20% was investigated. Fifty dogs were included: based on imaging and FC, 78.0% had stage 5 disease, 14.0% had stage 4, 6.0% had stage 3 and 2.0% had stage 1. By multivariable analysis, the CD4-negative phenotype was the only factor associated with a shorter TTP (P = 0.049), while BM infiltration was significantly associated with LSS (P = 0.037). Dogs with BM infiltration > 5% had shorter median LSS (114 days; 95%CI: 0-240) compared to dogs with BM infiltration ≤ 5% (178 days; 95%CI: 145-211). Lack of complete response (P = 0.039) and administration of corticosteroids before chemotherapy (P = 0.026) also significantly worsened LSS. BM flow cytometric evaluation could be considered an essential part of staging work-up for dogs with PTCL and has prognostic relevance.

Genomic Analysis of Lymphoma Risk in Bullmastiff Dogs

Lymphoma is the most common haematological malignancy affecting dogs and has a high incidence in the Bullmastiff breed. The aim of this study was to identify risk loci predisposing this breed to the disease. The average age of lymphoma diagnosis in 55 cases was less than 6 years, similar to the median age of 64 cases from our clinical and pathology databases. When fine-scale population structure was explored using NETVIEW, cases were distributed throughout an extended pedigree. When genotyped cases (n = 49) and dogs from the control group (n = 281) were compared in a genome-wide association analysis of lymphoma risk, the most prominent associated regions were detected on CFA13 and CFA33. The top SNPs in a 5.4 Mb region on CFA13 were significant at a chromosome-wide level, and the region was fine-mapped to ~1.2 Mb (CFA13: 25.2-26.4 Mb; CanFam3.1) with four potential functional candidates, including the MYC proto-oncogene bHLH transcription factor (MYC) and a region syntenic with the human and mouse lncRNA Pvt1 oncogene (PVT1). A 380 Kb associated region at CFA33: 7.7-8.1 Mb contained the coding sequence for SUMO specific peptidase7 (SENP7) and NFK inhibitor zeta (NFKBIZ) genes. These genes have annotations related to cancer, amongst others, and both have functional links to MYC regulation. Genomic signatures identified in lymphoma cases suggest that increased risk contributed by the regions identified by GWAS may complement a complex predisposing genetic background.

The TiHoCL panel for canine lymphoma: a feasibility study integrating functional genomics and network biology approaches for comparative oncology targeted NGS panel design

Targeted next-generation sequencing (NGS) enables the identification of genomic variants in cancer patients with high sensitivity at relatively low costs, and has thus opened the era to personalized human oncology. Veterinary medicine tends to adopt new technologies at a slower pace compared to human medicine due to lower funding, nonetheless it embraces technological advancements over time. Hence, it is reasonable to assume that targeted NGS will be incorporated into routine veterinary practice in the foreseeable future. Many animal diseases have well-researched human counterparts and hence, insights gained from the latter might, in principle, be harnessed to elucidate the former. Here, we present the TiHoCL targeted NGS panel as a proof of concept, exemplifying how functional genomics and network approaches can be effectively used to leverage the wealth of information available for human diseases in the development of targeted sequencing panels for veterinary medicine. Specifically, the TiHoCL targeted NGS panel is a molecular tool for characterizing and stratifying canine lymphoma (CL) patients designed based on human non-Hodgkin lymphoma (NHL) research outputs. While various single nucleotide polymorphisms (SNPs) have been associated with high risk of developing NHL, poor prognosis and resistance to treatment in NHL patients, little is known about the genetics of CL. Thus, the ~100 SNPs featured in the TiHoCL targeted NGS panel were selected using functional genomics and network approaches following a literature and database search that shielded ~500 SNPs associated with, in nearly all cases, human hematologic malignancies. The TiHoCL targeted NGS panel underwent technical validation and preliminary functional assessment by sequencing DNA samples isolated from blood of 29 lymphoma dogs using an Ion Torrent™ PGM System achieving good sequencing run metrics. Our design framework holds new possibilities for the design of similar molecular tools applied to other diseases for which limited knowledge is available and will improve drug target discovery and patient care.

Insight into the potential candidate genes and signaling pathways involved in lymphoma disease in dogs using a comprehensive whole blood transcriptome analysis

Lymphoma is one of the most prevalent hematological cancers, accounting for 15-20 % of new cancer diagnoses in dogs. Therefore, this study aims to explore the important genes and pathways involved in canine lymphoma progression and understand the underlying molecular mechanisms using RNA sequencing. In this study, RNAs acquired from seven pairs of lymphoma and non-lymphoma blood samples were sequenced from different breeds of dogs. Sequencing reads were preprocessed, aligned with the reference genome, assembled and expressions were estimated through bioinformatics approaches. At a false discovery rate (FDR) < 0.05 and fold change (FC) ≥ 1.5, a total of 625 differentially expressed genes (DEGs) were identified between lymphoma and non-lymphoma samples, including 347 up-regulated DEGs such as SLC38A11, SCN3A, ZIC5 etc. and 278 down-regulated DEGs such as LOC475937, CSMD1, KRT14 etc. GO enrichment analysis showed that these DEGs were highly enriched for molecular function of ATP binding and calcium ion binding, cellular process of focal adhesion, and biological process of immune response, and defense response to virus. Similarly, KEGG pathways analysis revealed 11 significantly enriched pathways such as ECM-receptor interaction, cell cycle, PI3K-Akt signaling pathway, ABC transporters etc. In the protein-protein interaction (PPI) network, CDK1 was found to be a top hub gene with highest degree of connectivity. Three modules selected from the PPI network showed that canine lymphoma was highly associated with cell cycle, ECM-receptor interaction, hypertrophic cardiomyopathy, dilated cardiomyopathy and RIG-I-like receptor signaling pathway. Overall, our findings highlighted new candidate therapeutic targets for further testing in canine lymphoma and facilitate the understanding of molecular mechanism of lymphoma's progression in dogs.

Diagnostic accuracy of ultrasonography to detect hepatic and splenic lymphomatous infiltration in dogs and cats

OBJECTIVES

To determine the diagnostic accuracy of ultrasonography in the detection of lymphomatous infiltration of the liver and spleen in a population of dogs and cats with lymphoma. To determine if specific ultrasonographic features of the liver and spleen in dogs are associated with lymphomatous infiltration or a specific immunophenotype of multi-centric lymphoma.

MATERIALS AND METHODS

A blinded retrospective evaluation of ultrasonographic images of the liver and/or spleen in dogs and cats with cytologically or histologically confirmed lymphoma was performed by two board-certified veterinary radiologists.

RESULTS

A total of 161 animals met the inclusion criteria, comprising 132 dogs and 29 cats. Ultrasonography had a sensitivity, specificity, accuracy, positive predictive value and negative predictive value of 16.7%, 91.0%, 55.9%, 62.5% and 55.0% for the detection of lymphomatous infiltration of the liver, and 73.1%, 93.9%, 82.6%, 93.4% and 74.7% for the spleen. In dogs, an ultrasonographically normal liver was associated with not having lymphomatous infiltration, leopard-spotted splenic parenchyma and splenomegaly were independently associated with lymphomatous infiltration and leopard-spotted splenic parenchyma was also associated with the B cell immunophenotype of multi-centric lymphoma.

CLINICAL SIGNIFICANCE

Ultrasonography of the spleen and liver is specific but not sensitive in the detection of lymphomatous infiltration. A leopard-spotted splenic parenchyma in dogs is highly specific for lymphomatous infiltration and in this population predicted a specific immunophenotype of multi-centric lymphoma.

Comparison between computed tomographic and ultrasonographic findings of the liver and spleen in dogs with confirmed hepatic or splenic lymphoma involvement

BACKGROUND

Computed tomography (CT) and ultrasonography (US) may be used to assist staging in dogs with lymphoma. The imaging features of splenic and hepatic infiltration have never been directly compared in the same population of dogs.

METHODS

The aim of this retrospective study was to describe and compare the CT and US findings of the liver and spleen in dogs with confirmed hepatic and/or splenic lymphoma and compare imaging and cytological diagnoses.

RESULTS

CT and US studies of 18 dogs with multicentric lymphoma involving the liver and/or the spleen were retrospectively evaluated. US detected abnormalities more frequently than CT in the spleen with lymphoma, whereas CT detected abnormalities more frequently in the liver with lymphoma. The two diagnostic imaging modalities often disagreed in the findings, including the imaging classification of the organ as normal or abnormal.

CONCLUSION

US and CT often disagree in the imaging findings present in hepatic and splenic lymphoma. The results of this study suggest that cytologic evaluation of both the liver and spleen is advisable regardless of their US or CT appearance for detection of lymphoma.

Construction and validation of a scoring system to predict resistance to chemotherapeutic drugs using gene expression profiles in canine lymphoma

The present study aimed to verify the changes in the expression levels of 13 candidate genes associated with chemotherapy resistance and to construct a scoring system to predict resistance to these drugs. The expression levels of the 13 candidate genes were compared between 20 dogs with lymphoma that were sensitive to drugs used in CHOP-based protocol and 16 dogs with lymphoma that were resistant to these drugs. The expression levels of six genes; ASNS, CCR3, CALCA, FCER1A, LOC448801, and EDNRB were significantly different between the two groups. A scoring system to predict resistance to cyclophosphamide, doxorubicin and vincristine, which are used in CHOP-based protocol, was constructed based on expression levels of the six genes in these 36 dogs using logistic regression models. After internal validation, sensitivity and specificity of the scoring system were 0.759 and 0.853, respectively. External validation was conducted in another cohort of 33 dogs with lymphoma, and sensitivity and specificity of the scoring system were 0.800 and 0.696, respectively. In conclusion, this study identified six genes associated with resistance to drugs used in CHOP-based protocol in canine lymphoma and proposed a novel scoring system to predict resistance to these drugs. This system might be beneficial in selecting the most appropriate chemotherapy protocol for individual dogs with lymphoma.

Demographic and clinical characteristics of dogs with centroblastic lymphoma

Background and Aim:

Centroblastic lymphoma (CBL) is the most common morphological type of lymphoma found in dogs; it is usually identified through cytology in veterinary clinical practice. This study aimed to identify the demographic and clinical characteristics of dogs with CBL that was diagnosed with cytology and immunocytochemistry.

Materials and Methods:

Dogs with a suspicion of lymphoma were diagnosed by cytology supported by immunocytochemistry with the use of the updated Kiel classification adapted for dogs. During the analyzed time period, 336 lymphomas were diagnosed in dogs, including 171 cases of CBL. Epidemiological and clinical data from the dogs with CBL were provisionally collected.

Results:

The epidemiology analysis revealed an increased risk of CBL in Rottweilers, golden retrievers, and Bernese mountain dogs. At admission, most of the dogs displayed generalized lymphadenopathy with spleen and liver enlargement. The most common hematological abnormality was leukocytosis due to neutrophilia. The most common biochemical abnormality was elevated alanine aminotransferase and alkaline phosphatase activities and selective hypoproteinemia due to hypoalbuminemia.

Conclusion:

Rottweilers, Bernese mountain dogs, and golden retrievers appear to be overrepresented among dogs with CBL. CBL is usually diagnosed at an advanced clinical stage according to the World Health Organization; however, it is usually accompanied by only minor hematological and biochemical abnormalities.

Pharmacokinetics of multivesicular liposomal encapsulated cytarabine when administered subcutaneously in dogs

Background

Prolonged cytotoxic concentrations of cytarabine (CA) are required for maximum cytotoxicity. DepoCyt is a human liposomal cytarabine (LC) product that lasts longer in plasma and CSF compared with free CA (FC). The use of LC has not been evaluated in dogs.

Objectives

To perform a LC pharmacokinetic (PK) study when administered SC in dogs.

Animals

Five healthy female beagles.

Methods

Three‐period, 3‐treatment, nonblinded, randomized, and crossover design, including a pilot study. LC was administered at 50 mg/m² SC and FC was administered at 25 and 50 mg/m² SC and IV. Plasma CA concentrations were measured until 240, 72, and 8 hours after SC LC, SC FC, and IV FC administration, respectively. CA plasma concentrations were quantitated by ultra‐high‐performance liquid chromatography with mass spectrometry (MS/MS) detection and concentration‐time profiles were evaluated by noncompartmental analysis.

Results

Subcutaneous LC administration resulted in a maximum plasma concentration of 26.3 to 59.78 ng/mL, time to reach maximum plasma concentration of 2 hours, area under the concentration‐time curve to last measurable concentration of 669.3 to 1126 h × ng/mL, and plasma bioavailability (%F) of 19.6% to 31.3%. The PK profiles of FC after SC and IV administration differed when compared with LC.

Conclusions and Clinical Importance

In healthy dogs, SC LC administration at 50 mg/m² results in measurable plasma CA concentrations, is apparently safe and well tolerated, but does not result in prolonged cytotoxic plasma concentrations. Poor absorption of LC prevented establishment of a complete LC PK profile.

Retrospective study of small pet tumors treated with Artemisia annua and iron

Artemisinin from Artemisia annua L. and its derivatives are well-known antimalarial drugs. In addition, in vitro studies, in vivo studies and clinical trials have demonstrated that these drugs exhibit anticancer activity in human patients with cancer. Therefore, the aim of the present study was to investigate whether a phytotherapeutic A. annua preparation exerts anticancer activity in veterinary tumors of small pets. Dogs and cats with spontaneous cancer (n=20) were treated with standard therapy plus a commercial A. annua preparation (Luparte^®) and compared with a control group treated with standard therapy alone (n=11). Immunohistochemical analyses were performed with formalin-fixed paraffin-embedded tumor biopsies to analyze the expression of transferrin receptor (TfR) and the proliferation marker Ki-67 as possible biomarkers to assess treatment response of tumors to A. annua. Finally, the expression levels of TfR and Ki-67 were compared with the IC₅₀ values towards artemisinin in two dog tumor cells lines (DH82 and DGBM) and a panel of 54 human tumor cell lines. Retrospectively, the present study assessed the survival times of small animals treated by standard therapy with or without A. annua. A. annua treatment was associated with a significantly higher number of animals surviving >18 months compared with animals without A. annua treatment (P=0.0331). Using a second set of small pet tumors, a significant correlation was identified between TfR and Ki-67 expression by immunohistochemistry (P=0.025). To further assess the association of transferrin and Ki-67 expression with cellular response to artemisinin, the present study compared the expression of these two biomarkers and the IC₅₀ values for artemisinin in National Cancer Institute tumor cell lines in vitro. Both markers were inversely associated with artemisinin response (P<0.05), and the expression levels of TfR and Ki-67 were significantly correlated (P=0.008). In conclusion, the promising results of the present retrospective study warrant further confirmation by prospective studies in the future.

Significant advances in veterinary oncology - 60 years on

The first edition of the Journal of Small Animal Practice published in February 1960, contained a paper entitled "Recent Treatments of Malignant Neoplasia" by Dr Larry Owen. Now we have reached the 60th anniversary of JSAP, that article provides a baseline from which to review subsequent advances in veterinary oncology, which now includes worldwide networks that have resulted in veterinary oncology becoming the multidisciplinary speciality that it is today. There certainly have been many advances in understanding of the pathology and epidemiology of animal cancers and in methods of diagnosis and treatment. However, the subject has become so large and diverse that not all aspects can be covered in detail here. It should also be acknowledged that there are still many gaps in knowledge in this field and that, because of a lack of randomised clinical trials, the evidence base for what is often regarded as "standard of care" is weak.

Expression of blood hepatocyte-derived microRNA-122 in canine multicentric lymphoma with hepatic involvement

This study was performed to evaluate the hepatocyte-derived microRNA (miR)-122 as novel diagnostic biomarker in canine lymphoma. Fifteen dogs were enrolled in this study. Dogs presented at Small Animal Teaching Hospital, Faculty of Veterinary Medicine, Cairo University. Dogs were divided into 8 clinically healthy dogs act as control and 7 clinically ill dogs. All dogs were subjected to clinical, ultrasonographic, hemato-biochemical and ultrasound-guided fine-needle biopsy for cytological and histopathological investigations. On the basis of these results, 7 dogs were found to be suffering from multicentric lymphoma involving liver. Serum hepatocyte-derived miRA-122 was determined by real-time quantitative polymerase chain reaction in all dogs. Multicentric lymphoma involving liver manifested by inappetance for several days, depression and peripheral lymphadenopathy. Hematological examination showed significant lymphocytosis. Serum biochemical analysis revealed significant increase in ALT, AST, ALP compared to control dogs. Ultrasonography revealed hypoechoic lymphoid aggregation at area of "porta hepatis" and circumscribed hypoechoic nodule interrupt liver parenchyma. Cytology revealed infiltration of liver tissue by lymphoblast cells and histopathology revealed diffuse infiltration of hepatic sinusoids and portal area by uniform population of small lymphocytes. Serum miRNA-122 analysis showed a significant increase represented as 9.00 fold in canine multicentric lymphoma involving liver. Serum hepatocyte-derived miRNA-122 is of diagnostic value, non invasive, stable and easily measurable blood biomarker for the detection of hepatocellular injury in dogs with multicentric lymphoma involving liver.

Tel-eVax: a genetic vaccine targeting telomerase for treatment of canine lymphoma

BACKGROUND

we have recently shown that Tel-eVax, a genetic vaccine targeting dog telomerase (dTERT) and based on Adenovirus (Ad)/DNA Electro-Gene-Transfer (DNA-EGT) technology can induce strong immune response and increase overall survival (OS) of dogs affected by multicentric Diffuse Large B cell Lymphoma (DLBCL) when combined to COP therapy in a double-arm study. Here, we have utilized a clinically validated device for veterinary electroporation called Vet-ePorator™, based on Cliniporator™ technology currently utilized and approved in Europe for electrochemotherapy applications and adapted to electrogenetransfer (EGT).

METHODS

17 dogs affected by DLBCL were vaccinated using two Ad vector injections (Prime phase) followed by DNA-EGT (Boost phase) by means of a Vet-ePorator™ device and treated in the same time with a 27-week Madison Wisconsin CHOP protocol. The immune response was measured by ELISA assays using pool of peptides.

RESULTS

No significant adverse effects were observed. The OS of vaccine/CHOP animals was 64.5 weeks, in line with the previous study. Dogs developed antibodies against the immunizing antigen.

CONCLUSIONS

Tel-eVax in combination with CHOP is safe and immunogenic in lymphoma canine patients. These data confirm the therapeutic efficacy of dTERT vaccine and hold promise for the treatment of dogs affected by other cancer types. More importantly, our findings may translate to human clinical trials and represent new strategies for cancer treatment.

Phase II study of the oral selective inhibitor of nuclear export (SINE) KPT-335 (verdinexor) in dogs with lymphoma

Background

Chemotherapeutic options for the treatment of canine lymphoma have not changed in several decades necessitating the identification of new therapeutics to improve patient outcome. KPT-335 (verdinexor) is a novel orally bioavailable selective inhibitor of nuclear export (SINE) that exhibited anti-tumor activity against non-Hodgkin lymphoma in a prior phase I study. The objective of this phase II study was to expand upon the initial findings and assess the activity and safety in a larger population of dogs with lymphoma.

Results

Fifty-eight dogs with naïve or progressive B-cell and T-cell lymphoma were enrolled in this clinical trial. KPT-335 was administered orally in one of three dosing groups, based on the previously established biologically active dose of 1.5 mg/kg three times weekly. Treatment with single-agent, orally administered KPT-335 resulted in an objective response rate (ORR) of 37%, of which dogs with T-cell lymphoma had an ORR of 71%. KPT-335 was well tolerated in all dose groups with grade 1–2 anorexia being the most common adverse event. Anorexia was responsive to symptomatic and supportive medications, including prednisone.

Conclusions

These data demonstrate that KPT-335 has biologic activity in canine lymphoma, and support continued evaluation of SINE compounds such as KPT-335 in combination with standard chemotherapeutics in canine lymphoma.

Electronic supplementary material

The online version of this article (10.1186/s12917-018-1587-9) contains supplementary material, which is available to authorized users.

Enantiomeric trans β-aryl-δ-iodo-γ-lactones derived from 2,5-dimethylbenzaldehyde induce apoptosis in canine lymphoma cell lines by downregulation of anti-apoptotic Bcl-2 family members Bcl-xL and Bcl-2

For many years, studies focused on developing new natural or synthetic compounds with antineoplastic activity have attracted the attention of researchers. An interesting group of such compounds seem to be those with both lactone moiety and an aromatic ring which, in addition to antimicrobial or antiviral activity, also exhibit antitumor properties. The study shows antitumor activity of two enantiomeric trans isomers of 5-(1-iodoethyl)-4-(2',5'-dimethylphenyl)dihydrofuran-2-one. Our aim was to determine their antitumor activity manifested as an ability to induce apoptosis in selected canine cancer cell lines as well as to evaluate differences in their strength depending on the configuration of their stereogenic centers. The enantiomers (+)-(4R,5S,6R)-1 and (-)-(4S,5R,6S)-2 were found to induce classical caspase-dependent apoptosis through downregulation of the expression of anti-apoptotic proteins Bcl-xL and Bcl-2. Although the mechanism of apoptosis induction was the same for both enantiomers, they differed in their strength, as stronger antineoplastic activity in vitro was exhibited by isomer (+)-(4R,5S,6R)-1.

Anti-tumor effects of perphenazine on canine lymphoma

Lymphoma is one of the most common malignant tumors in canine. Protein phosphatase 2A (PP2A), a well-conserved serine/threonine phosphatase, plays a critical role as a tumor suppressor. Perphenazine (PPZ) is one of the phenothiazines and widely used as an antipsychotic drug. Recently, it is reported that PPZ directly binds with scaffolding subunit of PP2A complex and exerts anti-tumor effects on human T cell acute lymphoblastic leukemia. However, the effect of PPZ on canine lymphoma has not been studied. Here, we investigated the potential therapeutic role of PPZ and its molecular mechanism in canine T-cell lymphoma. In canine T-cell lymphoma cell lines, UL-1 and Ema, PPZ decreased cell survival in a dose-dependent manner. Increased caspase 3 activity and Annexin V positive cells suggested that PPZ induced apoptosis. PPZ dephosphorylated Akt, MEK1/2 and ERK1/2. Akt inhibitor, but not MEK1/2 inhibitor and ERK1/2 inhibitor, induced cell death, indicating the importance of Akt dephosphorylation for the anti-tumor effect of PPZ. Finally, we observed enhanced PP2A activity by PPZ treatment. The present results for the first time revealed that PPZ induced canine lymphoma cells apoptosis through Akt dephosphorylation via PP2A activation. Our study suggests the possible therapeutic application of phenothiazines for canine T-cell lymphoma.

Newcastle Disease Virus: Potential Therapeutic Application for Human and Canine Lymphoma

Research on oncolytic viruses has mostly been directed towards the treatment of solid tumors, which has yielded limited information regarding their activity in hematological cancer. It has also been directed towards the treatment of humans, yet veterinary medicine may also benefit. Several strains of the Newcastle disease virus (NDV) have been used as oncolytics in vitro and in a number of in vivo experiments. We studied the cytolytic effect of NDV-MLS, a low virulence attenuated lentogenic strain, on a human large B-cell lymphoma cell line (SU-DHL-4), as well as on primary canine-derived B-cell lymphoma cells, and compared them to healthy peripheral blood mononuclear cells (PBMC) from both humans and dogs. NDV-MLS reduced cell survival in both human (42% ± 5%) and dog (34% ± 12%) lymphoma cells as compared to untreated controls. No significant effect on PBMC was seen. Cell death involved apoptosis as documented by flow-cytometry. NDV-MLS infections of malignant lymphoma tumors in vivo in dogs were confirmed by electron microscopy. Early (24 h) biodistribution of intravenous injection of 1 × 10¹² TCID₅₀ (tissue culture infective dose) in a dog with T-cell lymphoma showed viral localization only in the kidney, the salivary gland, the lung and the stomach by immunohistochemistry and/or endpoint PCR. We conclude that NDV-MLS may be a promising agent for the treatment of lymphomas. Future research is needed to elucidate the optimal therapeutic regimen and establish appropriate biosafety measures.

Enhanced therapeutic effect of APAVAC immunotherapy in combination with dose-intense chemotherapy in dogs with advanced indolent B-cell lymphoma

The aim of this non-randomized controlled trial was to compare time to progression (TTP), lymphoma-specific survival (LSS), and safety of an autologous vaccine (consisting of hydroxyapatite ceramic powder and Heat Shock Proteins purified from the dogs' tumors, HSPPCs-HA) plus chemotherapy versus chemotherapy alone in dogs with newly diagnosed, clinically advanced, histologically confirmed, multicentric indolent B-cell lymphoma. The vaccine was prepared from dogs' resected lymph nodes and administered as an intradermal injection. Forty-five client-owned dogs were enrolled: 20 dogs were treated with dose-intense chemotherapy, and 25 received concurrent immunotherapy. Both treatment arms were well tolerated, with no exacerbated toxicity in dogs also receiving the vaccine. TTP was significantly longer for dogs treated with chemo-immunotherapy versus those receiving chemotherapy only (median, 209 versus 85 days, respectively, P=0.015). LSS was not significantly different between groups: dogs treated with chemo-immunotherapy had a median survival of 349 days, and those treated with chemotherapy only had a median survival of 200 days (P=0.173). Among vaccinated dogs, those mounting an immune response had a significantly longer TTP and LSS than those with no detectable response (P=0.012 and P=0.003, respectively). Collectively these results demonstrate that vaccination with HSPPCs-HA may produce clinical benefits with no increased toxicity, thereby providing a strategy for enhancing chemotherapy in dogs with advanced indolent lymphoma.

Oxidative stress in dogs with multicentric lymphoma: Effect of chemotherapy on oxidative and antioxidant biomarkers

INTRODUCTION

Lymphoma is one of the most common types of cancer in dogs, characterized by the proliferation of lymphoid cells. The treatment of this type of cancer is usually based on drugs with high toxicity, which can cause severe side effects.

OBJECTIVES

Therefore, the aim of this study was to measure the levels of advanced oxidation protein products (AOPP), thiobarbituric acid reactive substances (TBARS), and ferric reducing antioxidant power (FRAP) in dogs with multicentric lymphoma before and after chemotherapy.

METHODS

For this purpose, serum samples of 25 dogs diagnosed with multicentric lymphoma and 15 healthy dogs were used. The animals were exposed to CHOP chemotherapy (cyclophosphamide, vincristine, doxorubicin, and prednisone) and serum samples were collected 5 weeks after treatment.

RESULTS

High levels of TBARS, AOPP, and FRAP were observed in sera of dogs with multicentric lymphoma when compared to healthy dogs (P < 0.01), and even higher levels (TBARS and AOPP) were found after chemotherapy i.e. treatment exacerbated the oxidative stress levels. On the other hand, FRAP levels did not differ statistically between animals with lymphoma before and after treatment (P > 0.05). Exacerbated oxidative stress was observed in dogs with multicentric lymphoma Group II (Stage IV-V: involvement of lymph nodes and organs) compared to those in Group I (Stage I-III: only affected lymph nodes) of the disease, as well as the dogs with clinical signs and T immunophenotype. Another important result was observed after chemotherapy, where FRAP levels were higher in dogs that showed complete disease remission compared to animals with progressive disease.

CONCLUSIONS

Therefore, dogs with lymphoma showed protein oxidation and lipid peroxidation, as well as increased total antioxidants before and after chemotherapy compared to the control group.

Peripheral blood lymphocyte/monocyte ratio as a useful prognostic factor in dogs with diffuse large B-cell lymphoma receiving chemoimmunotherapy

Diffuse large B-cell lymphoma (DLBCL) is the most frequent canine lymphoid neoplasm. Despite treatment, the majority of dogs with DLBCL experience tumour relapse and consequently die, so practical models to characterise dogs with a poor prognosis are needed. This study examined whether the lymphocyte/monocyte ratio (LMR) can predict outcome in dogs with newly diagnosed DLBCL with regard to time-to-progression (TTP) and lymphoma specific survival (LSS). A retrospective study analysed the prognostic significance of LMR obtained at diagnosis by flow cytometry (based on morphological properties and CD45 expression) in 51 dogs that underwent complete staging and received the same treatment, comprising multi-agent chemotherapy and administration of an autologous vaccine. Dogs with an LMR ≤ 1.2 (30% of all cases) were found to have significantly shorter TTP and LSS, and it was concluded that LMR was a useful independent prognostic indicator with biological relevance in dogs with DLBCL treated with chemoimmunotherapy.

Biology and Diseases of Dogs

Historically, the dog played an important role as a laboratory animal in biomedical research. Although numbers are declining, the use of dogs continues to be common in pharmacokinetics and cardiovascular studies. The normal biology of the dog as both a laboratory and a companion animal has been well studied and reference values are presented here as a clinical and experimental resource. This provides the necessary background to discuss the spontaneous diseases, including infectious and neoplastic conditions, prevalent in purpose bred as well as random source dogs used in biomedical research. In addition, diseases and conditions that arise secondary to the housing and experimental manipulation of dogs is discussed with emphasis on treatment and prevention.

Nucleo-cytoplasmic transport as a therapeutic target of cancer

Shuttling of specific proteins out of the nucleus is essential for the regulation of the cell cycle and proliferation of both normal and malignant tissues. Dysregulation of this fundamental process may affect many other important cellular processes such as tumor growth, inflammatory response, cell cycle, and apoptosis. It is known that XPO1 (Exportin-1/Chromosome Region Maintenance 1/CRM1) is the main mediator of nuclear export in many cell types. Nuclear proteins exported to the cytoplasm by XPO1 include the drug targets topoisomerase IIα (topo IIα) and BCR-ABL and tumor suppressor proteins such as Rb, APC, p53, p21, and p27. XPO1 can mediate cell proliferation through several pathways: (i) the sub-cellular localization of NES-containing oncogenes and tumor suppressor proteins, (ii) the control of the mitotic apparatus and chromosome segregation, and (iii) the maintenance of nuclear and chromosomal structures. The XPO1 protein is elevated in ovarian carcinoma, glioma, osteosarcoma, pancreatic and cervical cancer. There is a growing body of research indicating that XPO1 may have an important role as a prognostic marker in solid tumors. Because of this, nuclear export inhibition through XPO1 is a potential target for therapeutic intervention in many cancers. The best understood XPO1 inhibitors are the small molecule nuclear export inhibitors (NEIs; Leptomycin B and derivatives, ratjadones, PKF050-638, valtrate, ACA, CBS9106, selinexor/KPT-330, and verdinexor/KPT-335). Selinexor and verdinexor are orally bioavailable, highly potent, small molecules that are classified as Selective Inhibitors of Nuclear Export (SINE). KPT-330 is the only NEI currently in Phase I/II human clinical trials in hematological and solid cancers. Of all the potential targets in nuclear cytoplasmic transport, the nuclear export receptor XPO1 remains the best understood and most advanced therapeutic target for the treatment of cancer.

Array-based comparative genomic hybridization analysis reveals chromosomal copy number aberrations associated with clinical outcome in canine diffuse large B-cell lymphoma

Canine Diffuse Large B-cell Lymphoma (cDLBCL) is an aggressive cancer with variable clinical response. Despite recent attempts by gene expression profiling to identify the dog as a potential animal model for human DLBCL, this tumor remains biologically heterogeneous with no prognostic biomarkers to predict prognosis. The aim of this work was to identify copy number aberrations (CNAs) by high-resolution array comparative genomic hybridization (aCGH) in 12 dogs with newly diagnosed DLBCL. In a subset of these dogs, the genetic profiles at the end of therapy and at relapse were also assessed. In primary DLBCLs, 90 different genomic imbalances were counted, consisting of 46 gains and 44 losses. Two gains in chr13 were significantly correlated with clinical stage. In addition, specific regions of gains and losses were significantly associated to duration of remission. In primary DLBCLs, individual variability was found, however 14 recurrent CNAs (>30%) were identified. Losses involving IGK, IGL and IGH were always found, and gains along the length of chr13 and chr31 were often observed (>41%). In these segments, MYC, LDHB, HSF1, KIT and PDGFRα are annotated. At the end of therapy, dogs in remission showed four new CNAs, whereas three new CNAs were observed in dogs at relapse compared with the previous profiles. One ex novo CNA, involving TCR, was present in dogs in remission after therapy, possibly induced by the autologous vaccine. Overall, aCGH identified small CNAs associated with outcome, which, along with future expression studies, may reveal target genes relevant to cDLBCL.

Utility of a multiple serum biomarker test to monitor remission status and relapse in dogs with lymphoma undergoing treatment with chemotherapy

A blinded retrospective study was conducted to investigate remission and recurrence of lymphoma in dogs receiving chemotherapy. The objective was to compare clinicians' assessment using palpation and cytology to the results of serum biochemical tests for haptoglobin (Hapt) and C-reactive protein (C-RP). These biochemical test results were combined using a diagnostic algorithm developed using data from 344 individual dogs. This multivariate approach, termed the canine lymphoma blood test (cLBT), was used to follow 57 dogs during and after treatment. cLBT of remission and recurrence compared well with clinicians' assessment and differentiated dogs in remission and those with recurring disease before appearance of lymphadenopathy (P < 0.001). The cLBT demonstrated prognostic potential based on pre-treatment values on dogs with shorter survival times and on those achieving the lowest cLBT score during treatment that showed longer survival times. The test, therefore, demonstrates potential to assist in monitoring treatment of canine lymphoma.

Hematologic findings predictive of bone marrow disease in dogs with multicentric large-cell lymphoma

BACKGROUND

Evaluation of the bone marrow is needed for complete staging in dogs with multicentric large-cell lymphoma, but is often omitted in clinical practice.

OBJECTIVES

The objective was to determine if routine peripheral blood findings, including microscopic evaluation of blood smears, can predict the presence of bone marrow involvement in dogs with lymphoma.

METHODS

Hematologic data including evaluation of blood smears and bone marrow aspirates from 107 dogs newly diagnosed with large-cell lymphoma were retrospectively evaluated. Neoplastic lymphocytes were identified based on cell size, nuclear size, chromatin pattern, and the presence of nucleoli. Positive specimens were defined as having ≥ 10% neoplastic lymphocytes. Two groups were established based on the presence or absence of lymphoma in the bone marrow. Variables (positive blood smear, HCT, platelet count, and total and differential WBC counts) were evaluated to determine if they were predictive of bone marrow involvement using univariate and multivariate logistic models.

RESULTS

Thrombocytopenia and the presence of > 10% neoplastic lymphocytes on blood smears were identified as significant variables for predicting the presence of bone marrow involvement. When considered independently, either a positive blood smear or thrombocytopenia had low sensitivity (60%) and moderate specificity (89% and 87%, respectively). Sensitivity increased when these variables were evaluated together (80%).

CONCLUSIONS

In dogs with multicentric large-cell lymphoma, thrombocytopenia or the presence of neoplastic lymphocytes in circulation is suggestive of bone marrow involvement, but not definitive. Normal peripheral blood findings do not exclude the possibility of lymphoma in the bone marrow.

Dissecting the regulatory microenvironment of a large animal model of non-Hodgkin lymphoma: evidence of a negative prognostic impact of FOXP3+ T cells in canine B cell lymphoma

The cancer microenvironment plays a pivotal role in oncogenesis, containing a number of regulatory cells that attenuate the anti-neoplastic immune response. While the negative prognostic impact of regulatory T cells (Tregs) in the context of most solid tissue tumors is well established, their role in lymphoid malignancies remains unclear. T cells expressing FOXP3 and Helios were documented in the fine needle aspirates of affected lymph nodes of dogs with spontaneous multicentric B cell lymphoma (BCL), proposed to be a model for human non-Hodgkin lymphoma. Multivariable analysis revealed that the frequency of lymph node FOXP3⁺ T cells was an independent negative prognostic factor, impacting both progression-free survival (hazard ratio 1.10; p = 0.01) and overall survival (hazard ratio 1.61; p = 0.01) when comparing dogs showing higher than the median FOXP3 expression with those showing the median value of FOXP3 expression or less. Taken together, these data suggest the existence of a population of Tregs operational in canine multicentric BCL that resembles thymic Tregs, which we speculate are co-opted by the tumor from the periphery. We suggest that canine multicentric BCL represents a robust large animal model of human diffuse large BCL, showing clinical, cytological and immunophenotypic similarities with the disease in man, allowing comparative studies of immunoregulatory mechanisms.

Viral oncolysis - can insights from measles be transferred to canine distemper virus?

Neoplastic diseases represent one of the most common causes of death among humans and animals. Currently available and applied therapeutic options often remain insufficient and unsatisfactory, therefore new and innovative strategies and approaches are highly needed. Periodically, oncolytic viruses have been in the center of interest since the first anecdotal description of their potential usefulness as an anti-tumor treatment concept. Though first reports referred to an incidental measles virus infection causing tumor regression in a patient suffering from lymphoma several decades ago, no final treatment concept has been developed since then. However, numerous viruses, such as herpes-, adeno- and paramyxoviruses, have been investigated, characterized, and modified with the aim to generate a new anti-cancer treatment option. Among the different viruses, measles virus still represents a highly interesting candidate for such an approach. Numerous different tumors of humans including malignant lymphoma, lung and colorectal adenocarcinoma, mesothelioma, and ovarian cancer, have been studied in vitro and in vivo as potential targets. Moreover, several concepts using different virus preparations are now in clinical trials in humans and may proceed to a new treatment option. Surprisingly, only few studies have investigated viral oncolysis in veterinary medicine. The close relationship between measles virus (MV) and canine distemper virus (CDV), both are morbilliviruses, and the fact that numerous tumors in dogs exhibit similarities to their human counterpart, indicates that both the virus and species dog represent a highly interesting translational model for future research in viral oncolysis. Several recent studies support such an assumption. It is therefore the aim of the present communication to outline the mechanisms of morbillivirus-mediated oncolysis and to stimulate further research in this potentially expanding field of viral oncolysis in a highly suitable translational animal model for the benefit of humans and dogs.

Safety and efficacy of a genetic vaccine targeting telomerase plus chemotherapy for the therapy of canine B-cell lymphoma

Client-owned pet dogs represent exceptional translational models for advancement of cancer research because they reflect the complex heterogeneity observed in human cancer. We have recently shown that a genetic vaccine targeting dog telomerase reverse transcriptase (dTERT) and based on adenovirus DNA electro-gene-transfer (Ad/DNA-EGT) technology can induce strong cell-mediated immune responses against this tumor antigen and increase overall survival of dogs affected by B-cell lymphosarcoma (LSA) in comparison with historical controls when combined with a cyclophosphamide, vincristine, and prednisone (COP) chemotherapy regimen. Here, we have conducted a double-arm clinical trial with an extended number of LSA patients, measured the antigen-specific immune response, and evaluated potential toxic effects of the immunotherapy along with a follow-up of patients survival for 3.5 years. The immune response was measured by enzyme-linked immunospot assay. The expression of dTERT was quantified by quantitative polymerase chain reaction. Changes in hematological parameters, local/systemic toxicity or organic dysfunction and fever were monitored over time during the treatment. dTERT-specific cell-mediated immune responses were induced in almost all treated animals. No adverse effects were observed in any dog patient that underwent treatment. The overall survival time of vaccine/COP-treated dogs was significantly increased over the COP-only cohort (>76.1 vs. 29.3 weeks, respectively, p<0.0001). There was a significant association between dTERT expression levels in LSA cells and overall survival among vaccinated patients. In conclusion, Ad/DNA-EGT-based cancer vaccine against dTERT in combination with COP chemotherapy is safe and significantly prolongs the survival of LSA canine patients. These data confirm the therapeutic efficacy of dTERT vaccine and support the evaluation of this approach for other cancer types as well as the translation of this approach to human clinical trials.

Assessment of bone marrow infiltration diagnosed by flow cytometry in canine large B cell lymphoma: prognostic significance and proposal of a cut-off value

The aims of this study were to assess the prognostic significance of bone marrow (BM) infiltration in canine large B cell lymphoma (LBCL) and to establish cut-off values for designating the BM as infiltrated by lymphoid blasts. The degree of BM infiltration by large CD21 positive cells in dogs with LBCL was assessed by flow cytometry (FC) and related to time to progression (TTP) and lymphoma-specific survival (LSS). Forty-six dogs were prospectively enrolled, staged and treated with a dose-intense chemotherapeutic protocol. BM infiltration was directly correlated with peripheral blood infiltration (P=0.001), high lactate dehydrogenase activity (P=0.0024) and substage b disease (P<0.001). In the univariate analysis, there was a significant association between BM infiltration diagnosed by FC and both TTP (P=0.001) and LSS (P<0.001). Substage was the only factor associated with TTP in the multivariate analysis (P=0.002), whereas substage (P<0.001) and anaemia (P=0.008) were associated with LSS. A cut-off of 3% BM infiltration had the strongest prognostic value, since it discriminated between dogs with a poorer prognosis (median TTP 69 days; median LSS 155 days) and dogs with a better prognosis (median TTP 149 days; median LSS 322 days). BM analysis is an essential step in the staging of LBCL. The presence of BM infiltration by FC at diagnosis is a negative prognostic indicator in canine LBCL.

Flow-cytometric detection of phenotypic aberrancies in canine small clear cell lymphoma

Histopathology and immunohistochemistry are mandatory to solve the differential between canine low-grade lymphoma and reactive hyperplasia. However, clinicians and owners often show reluctance toward these invasive tests. However, molecular biology techniques are still not sensitive and specific enough to be regarded as a reliable tool for final diagnosis. In humans, flow cytometry (FC) allows a definitive diagnosis of T-cell lymphoma based on high prevalence of antigen aberrancies. We describe here the immunophenotype of 26 cases of suspect canine small-clear cell lymphoma, determined by multi-colour FC. All cases showed antigen aberrancies and therefore neoplasia was always confirmed. As a consequence, we argue that the combined use of cytology and FC allows solving the differential diagnosis between small clear cell lymphoma and non-neoplastic reactive conditions when histopathology is not available. Further studies are needed to establish if any aberrancy can be considered indicative of specific histotypes.

Evaluation of tyrosine-kinase receptor c-kit mutations, mRNA and protein expression in canine lymphoma: might c-kit represent a therapeutic target?

c-kit plays an important role in proliferation, survival and differentiation of hematopoietic progenitor cells. In human hematopoietic malignancies, c-kit is mostly expressed by progenitor cell neoplasms and seldom by mature cell neoplasms. Aim of this study was to evaluate c-kit expression in canine lymphoma. Twenty-five B-cell lymphomas and 21 T-cell lymphomas were enrolled in the study. c-kit mRNA and protein expression was measured in lymph node fine needle aspirates by quantitative real-time RT-PCR, flow cytometry and immunocytochemistry, while the occurrence of KIT mutations on exons 8-11 and 17 was investigated by direct cDNA sequencing. KIT mRNA was amplifiable but below the limit of quantification in 76% of B-cell lymphomas and 33% of T-cell lymphomas. Remaining samples showed a very low expression of KIT, except for some high grade (HG) T-cell lymphomas where a comparatively higher mRNA amount was observed. Transcriptional data were confirmed at the protein level. No gain-of-function mutations were observed. Among canine lymphomas, T-cell lymphoma typically shows an aggressive biological behavior, partly being attributable to the lack of efficacious treatment options, and the evidence of c-kit expression in HG T-cell lymphomas might represent the rationale for its routinely diagnostic evaluation and the use of tyrosine kinase inhibitors in future clinical trials.

Comparative RNA-Seq and microarray analysis of gene expression changes in B-cell lymphomas of Canis familiaris

Comparative oncology is a developing research discipline that is being used to assist our understanding of human neoplastic diseases. Companion canines are a preferred animal oncology model due to spontaneous tumor development and similarity to human disease at the pathophysiological level. We use a paired RNA sequencing (RNA-Seq)/microarray analysis of a set of four normal canine lymph nodes and ten canine lymphoma fine needle aspirates to identify technical biases and variation between the technologies and convergence on biological disease pathways. Surrogate Variable Analysis (SVA) provides a formal multivariate analysis of the combined RNA-Seq/microarray data set. Applying SVA to the data allows us to decompose variation into contributions associated with transcript abundance, differences between the technology, and latent variation within each technology. A substantial and highly statistically significant component of the variation reflects transcript abundance, and RNA-Seq appeared more sensitive for detection of transcripts expressed at low levels. Latent random variation among RNA-Seq samples is also distinct in character from that impacting microarray samples. In particular, we observed variation between RNA-Seq samples that reflects transcript GC content. Platform-independent variable decomposition without a priori knowledge of the sources of variation using SVA represents a generalizable method for accomplishing cross-platform data analysis. We identified genes differentially expressed between normal lymph nodes of disease free dogs and a subset of the diseased dogs diagnosed with B-cell lymphoma using each technology. There is statistically significant overlap between the RNA-Seq and microarray sets of differentially expressed genes. Analysis of overlapping genes in the context of biological systems suggests elevated expression and activity of PI3K signaling in B-cell lymphoma biopsies compared with normal biopsies, consistent with literature describing successful use of drugs targeting this pathway in lymphomas.

CD40-activated B cell cancer vaccine improves second clinical remission and survival in privately owned dogs with non-Hodgkin's lymphoma

Cell-based active immunotherapy for cancer is a promising novel strategy, with the first dendritic cell (DC) vaccine achieving regulatory approval for clinical use last year. Manufacturing remains arduous, especially for DC vaccines, and the prospect of using cell-based immunotherapy in the adjuvant setting or in combination with chemotherapy remains largely untested. Here, we used a comparative oncology approach to test the safety and potential efficacy of tumor RNA-loaded, CD40-activated B cells in privately owned dogs presenting with non-Hodgkin's lymphoma (NHL), a clinical scenario that represents not only a major problem in veterinary medicine but also a bona fide spontaneous animal model for the human condition. When administered to NHL dogs in remission after induction chemotherapy, CD40-B cells electroporated ex vivo with autologous tumor RNA safely stimulated immunity in vivo. Although chemotherapy plus CD40-B vaccination did not improve time-to-progression or lymphoma-specific survival compared to dogs treated with chemotherapy alone, vaccination potentiated the effects of salvage therapy and improved the rate of durable second remissions as well as subsequent lymphoma-specific survival following salvage therapy. Several of these relapsed dogs are now long-term survivors and free of disease for more than a year. Overall, these clinical and immunological results suggest that cell-based CD40 cancer vaccination is safe and synergizes with chemotherapy to improve clinical outcome in canine NHL. More broadly, our findings underscore the unique value of clinical investigations in tumor-bearing companion animals.