Breed incidence of lymphoma in a UK population of insured dogs

Analysis of vector genome integrations in multicentric lymphoma after AAV gene therapy in a severe hemophilia A dog

Adeno-associated viral (AAV) vectors have traditionally been viewed as predominantly nonintegrating, with limited concerns for oncogenesis. However, accumulating preclinical data have shown that AAV vectors integrate more often than previously appreciated, with the potential for genotoxicity. To understand the consequences of AAV vector integration, vigilance for rare genotoxic events after vector administration is essential. Here, we investigate the development of multicentric lymphoma in a privately owned dog, PC9, with severe hemophilia A that was treated with an AAV8 vector encapsidating a B domain-deleted canine coagulation F8 gene. PC9 developed an aggressive B cell lineage multicentric lymphoma 3.5 years after AAV treatment. Postmortem analysis of the liver, spleen, and lymph nodes showed the expected biodistribution of the AAV genome. Integration events were found both in PC9 and a second privately owned hemophilia A dog treated similarly with canine F8 gene transfer, which died of a bleeding event without evidence of malignancy. However, we found no evidence of expanded clones harboring a single integration event, indicating that AAV genome integrations were unlikely to have contributed to PC9's cancer. These findings suggest AAV integrations occur but are mostly not genotoxic and support the safety profile of AAV gene therapy.

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.

Lymphoma in Border Collies: Genome-Wide Association and Pedigree Analysis

There has been considerable interest in studying cancer in dogs and its potential as a model system for humans. One area of research has been the search for genetic risk variants in canine lymphoma, which is amongst the most common canine cancers. Previous studies have focused on a limited number of breeds, but none have included Border Collies. The aims of this study were to identify relationships between Border Collie lymphoma cases through an extensive pedigree investigation and to utilise relationship information to conduct genome-wide association study (GWAS) analyses to identify risk regions associated with lymphoma. The expanded pedigree analysis included 83,000 Border Collies, with 71 identified lymphoma cases. The analysis identified affected close relatives, and a common ancestor was identified for 54 cases. For the genomic study, a GWAS was designed to incorporate lymphoma cases, putative "carriers", and controls. A case-control GWAS was also conducted as a comparison. Both analyses showed significant SNPs in regions on chromosomes 18 and 27. Putative top candidate genes from these regions included DLA-79, WNT10B, LMBR1L, KMT2D, and CCNT1.

Characterization of canine intestinal microRNA expression in inflammatory bowel disease and T-cell lymphoma

Differentiating between canine inflammatory bowel disease (IBD) and intestinal T-cell lymphoma by histopathological examination of endoscopically-derived intestinal biopsies can be challenging and involves an invasive procedure requiring specialized equipment and training. A rapid, non-invasive method of diagnosis, such as blood or faecal analysis for a conserved and stable biomarker, would be a useful adjunct or replacement. Studies on dogs and humans with various types of lymphoma have shown altered microRNA (miRNA) expression patterns in blood, faeces and tissues indicating their potential use as biomarkers of disease. The present study used residual archived endoscopically-derived, formalin-fixed, paraffin-embedded (FFPE) duodenal tissue taken from pet dogs undergoing routine investigation of gastrointestinal disease. The dogs had previously been diagnosed with either normal/minimal intestinal inflammation, severe IBD or intestinal T-cell lymphoma. Next generation sequencing with qPCR validation was used to elucidate differentially expressed miRNAs between groups. Our results show that miRNA can be extracted from archived endoscopically-derived FFPE tissues from the canine duodenum and used to differentiate normal/minimally inflamed canine duodenal tissue from severe lymphoplasmacytic IBD and T-cell lymphoma.

Psychological Stress Is Associated with Increased Cancer Risk in Dogs

Although there is evidence that psychological stress may be associated with increased cancer risk, the effect of stress on cancer risk is difficult to study, both in humans, due to socioeconomic factors, and in animal models, due to questionable biological relevance. Here, we test whether heritable canine temperament that increases psychological stress is associated with cancer risk. The study data are breed-specific averages of incidences of multiple cancer types and of temperament classes. The latter are derived from a latent class analysis of behavioral questionnaires completed by owners (C-BARQ). We thus classified the dogs according to whether they are calm vs. reactive within and across breeds. Using meta-analysis approaches, we modeled the risk of multiple cancer types in calm vs. reactive dogs. We adjusted for breed averages of body mass and lifespan, which are common confounders that impact cancer. Our study confirms that body size has a significant effect of on risk of multiple types of cancers in dogs and shows for the first time that temperament also has a moderate effect. These findings suggest dog models of heritable psychological stress are suitable for molecular epidemiological and translational studies on its effects on cancer risk.

A bitesize introduction to canine hematologic malignancies

Hematologic malignancies are frequently diagnosed in dogs and result in a spectrum of clinical signs associated with specific disease types. The most frequently encountered hematologic tumors in dogs include lymphoma, lymphoid and myeloid leukemias, and mast cell, plasma cell, and histiocytic neoplasias. Coupled with the heterogeneous presentations of the different categories and subtypes of canine hematologic malignancies, outcomes for these tumors are also variable. Considering this, appropriate treatment options range from active surveillance to curative intent approaches harnessing surgical, chemotherapeutic, and radiation-based modalities. The underlying pathology of many of these diseases bears remarkable resemblance to that of the corresponding diagnosis made in human patients. We introduce some of the pathogenic drivers of canine hematologic cancers alongside their clinical presentations. An overview of standard-of-care therapies for each of these diseases is also provided. As comparative oncology gains recognition as a valuable setting in which to investigate the pathogenesis of neoplasia and provide powerful, clinically relevant, immunocompetent models for the evaluation of novel therapies, the number of clinicians and scientists participating in cancer research involving dogs is expected to increase. This review aims at providing an introductory overview of canine hematologic malignancies.

Mastiff breed mortality: A study of owner experience, dog age and longevity

•

Mastiffs are a group of large and giant powerful dogs consisting of 19 breeds worldwide.

•

The median age of death for the Mastiff group was 8 years with European and North American dogs also dying at this age.

•

A higher percentage of dogs died over 8 years when classed as senior within breed standards.

•

Cancer was the most common cause of death in the Mastiff group with osteosarcoma the most common specifically in neutered animals.

Despite being ranked 33 in Americas most popular breeds (American Kennel Club, 2020), there is a lack of research addressing longevity and death related health problems of Mastiff dog breeds and specifically commonly kept Bull Mastiffs and English Mastiffs. Likely a result of small founder populations and minimal breeding geographical locations, limited genetic variation is found making it important to determine key health concerns which may reduce longevity. The purpose of this study was to report findings from an online global survey of owners of deceased Mastiffs detailing breed, age at death, and if known, cause of death. Owner information was also collected including location by continent and country and the owners breeding or hobbyist experience. A closed-question survey was used via an online network of global Mastiff clubs and associations totalling a useable sample of 1036 dogs across a range of breeds. Notably, it is reported that age and cause of death varied dependant on breed. Results indicate that the median age of death for all dogs was 8 years with mean age of death in Europe as 7.72 years and 8.17 years in North America. The most common cause of death identified for all dogs was cancer (47%), old age (16%), cardiac problems (8%) and gastric problems including GDV and bloat (7%). The mean age of death for cancer dogs was 7.85 years with 23 types of cancer stated with Osteosarcoma being the most commonly recorded and specifically for neutered animals. As the survey was aimed at hobbyist and registered breeders, study findings contribute to knowledge of Mastiff mortality with the aim of promoting welfare of the breed.

Dog leukocyte antigen-88*034:01 presents nonamer peptides from canine distemper virus hemagglutinin, large polymerase, and matrix proteins

Canine spontaneous cancers may offer greater fidelity than rodent models in advancing clinical immunotherapies. Boxers in particular are distinguished as study subjects by their popularity, and high incidence of human-relevant cancers. Further, the MHC class I allele DLA-88*034:01, with a known motif, dominates the breed, facilitating discovery of shared CTL responses against mutation-origin neoepitopes by standard prediction methods. We experimentally confirmed the allomorph's binding motif by developing an MHC surface stabilization assay. The assay validated four DLA-88*034:01-presented peptides from canine distemper virus, ubiquitously administered in routine vaccines, for positive controls in future CTL studies. In turn, these viral peptides substantiated motif-based prediction for DLA-88*034:01. The study adds new tools for studying neoepitope-specific CTL in Boxers to foster canine comparative oncology.

Expression of P-glycoprotein and breast cancer resistance protein in three cases of canine lymphoma showing drug resistance

In canine lymphoma, drug resistance is the major factor hindering treatment. In this study, we performed immunohistochemical examination of P-glycoprotein (P-gp) and breast cancer resistance protein (BCRP), which are considered as transporters related to multidrug resistance in three recurrent canine lymphomas. All cases were negative for both transporters before anticancer drug administration, but became positive after this administration. The expression was confirmed in capillary endothelial cells, such as in brain capillaries acting as the blood-brain barrier (BBB). It is suggested that both transporters expressed on capillary endothelial cells in lymphoma tissue may inhibit the spread of anticancer drugs into tumor tissues from blood, the same as the BBB. Therefore, capillary endothelial cells could act as a blood-tumor barrier, which might be involved in drug resistance in canine lymphoma.

Genetic and environmental risk for lymphoma in boxer dogs

BACKGROUND

Non-Hodgkin lymphoma in humans is associated with environmental chemical exposures, and risk is enhanced by genetic variants in glutathione S-transferases (GST) enzymes.

OBJECTIVE

We hypothesized that boxer dogs, a breed at risk for lymphoma, would have a higher prevalence of GST variants with predicted low activity, and greater accumulated DNA damage, compared to other breeds. We also hypothesized that lymphoma in boxers would be associated with specific environmental exposures and a higher prevalence of canine GST variants.

ANIMALS

Fifty-four healthy boxers and 56 age-matched nonboxer controls; 63 boxers with lymphoma and 89 unaffected boxers ≥10 years old.

METHODS

We resequenced variant loci in canine GSTT1, GSTT5, GSTM1, and GSTP1 and compared endogenous DNA damage in peripheral leukocytes of boxers and nonboxers using the comet assay. We also compared GST variants and questionnaire-based environmental exposures in boxers with and without lymphoma.

RESULTS

Endogenous DNA damage did not differ between boxers and nonboxers. Boxers with lymphoma were more likely to live within 10 miles of a nuclear power plant and within 2 miles of a chemical supplier or crematorium. Lymphoma risk was not modulated by known canine GST variants.

CONCLUSIONS AND CLINICAL IMPORTANCE

Proximity to nuclear power plants, chemical suppliers, and crematoria were significant risk factors for lymphoma in this population of boxers. These results support the hypothesis that aggregate exposures to environmental chemicals and industrial waste may contribute to lymphoma risk in dogs.

Histopathological and immunophenotypical characterization of canine multicentric lymphoma in Brazil: a study of 203 cases

ABSTRACT The immunophenotype is regarded as an independent prognostic factor in high-grade lymphomas, seeing that lymphomas of T-cell origin are associated with shorter survival time. Although a number of studies have evaluated the immunophenotypical profile of lymphoma in the USA and Europe, Brazilian research on the matter remains scarce. Exact characterization of the histopathological type is crucial to establish proper treatment and prognosis. This study evaluated the database of immunohistochemistry laboratories that perform immunophenotyping of canine lymphoma in Brazil. A total of 203 cases of multicentric lymphoma were classified according to the WHO classification. Immunophenotyping was able to identify 71.4% lymphomas of B-cell line, 27.1% of T-cell line and 1.5% of non-B cells and non-T cell lines. Diffuse large B-cell lymphoma was the most common with 59.1% of the cases. Among T-cell lymphomas, lymphoblastic was the most common (11.33% of the cases). Even though canine lymphomas tend to be high-grade, indolent lymphomas comprised 11.82% of the cases and T-zone lymphoma was the most prevalent (8.86%). The immunophenotype of multicentric lymphoma in Brazil is similar to those in other parts of the world, which suggests similar etiologic factors to the development of this disease.

MicroRNA profiling in canine multicentric lymphoma

Lymphoma is the most common hematopoietic tumour in dogs and is remarkably similar to the human disease. Tumour biomarker discovery is providing new tools for diagnostics and predicting therapeutic response and clinical outcome. MicroRNAs are small non-coding RNAs that participate in post-transcriptional gene regulation and their aberrant expression can impact genes involved in cancer. The aim of this study was to characterize microRNA expression in lymph nodes and plasma from dogs with multicentric B or T cell lymphoma compared to healthy control dogs. We further compared expression between lymph nodes and corresponding plasma samples and assessed changes in expression at relapse compared to time of diagnosis. Lastly, we investigated microRNAs for association with clinical outcome in patients treated with CHOP chemotherapy. A customized PCR array was utilized to profile 38 canine target microRNAs. Quantification was performed using real time RT-qPCR and relative expression was determined by the delta-delta Ct method. In lymph nodes, there were 16 microRNAs with significantly altered expression for B cell lymphoma and 9 for T cell lymphoma. In plasma, there were 15 microRNAs altered for B cell lymphoma and 3 for T cell lymphoma. The majority of microRNAs did not have correlated expression between lymph node and plasma and only 8 microRNAs were significantly different between diagnosis and relapse. For B cell lymphoma, 8 microRNAs had differential expression in the non-remission group compared to dogs that completed CHOP in complete remission. Four of these microRNAs were also altered in patients that died prior to one-year. Kaplan-Meier survival curves for high versus low microRNA expression revealed that 10 microRNAs were correlated with progression-free survival and 3 with overall survival. This study highlights microRNAs of interest for canine multicentric lymphoma. Future goals include development of microRNA panels that may be useful as biomarkers with the intent to provide improved outcome prediction to veterinary cancer patients.

Geographic distribution and environmental risk factors of lymphoma in dogs under primary-care in the UK

OBJECTIVES

To integrate external data sources with VetCompass postcode data to explore the spatial distribution and examine potential associations with environmental risk factors in dogs diagnosed with lymphoma at primary care veterinary practices.

MATERIALS AND METHODS

Cases of lymphoma were identified from electronic patient records of 455,553 dogs under primary veterinary care during 2013 in the UK. Cases were defined as either laboratory-confirmed or non-laboratory-confirmed. Disease maps at the postcode-district level were used to define the geographic distribution of lymphoma incidence and spatial clustering was explored. Environmental risk factors from external data sources were transferred to a compatible format and logistic regression modelling was used to examine associations between environmental herbicide, fungicide and radon concentrations with lymphoma.

RESULTS

From the denominator population of 455,553 dogs, 279 lymphoma cases (187 with laboratory confirmation and 93 without) were identified. Heterogeneous geographic variation was observed with weak evidence of clustering around London and the south-west of England. Herbicide and fungicide exposures were weakly associated with a diagnosis of lymphoma in the univariable analysis. After accounting for the age at diagnosis and breed in the multivariable analysis, herbicide exposure was associated with a diagnosis of lymphoma.

CLINICAL SIGNIFICANCE

The heterogeneous distribution of lymphoma in UK dogs provides further evidence for geographic variation of lymphoma, perhaps in part associated with underlying environmental risk factors. The results suggest an association between environmental herbicide and canine lymphoma.

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.

Incidence and risk factors for the diagnosis of lymphoma in dogs in UK primary-care practice

OBJECTIVES

To identify the incidence, risk factors and presenting signs of lymphoma in dogs presenting to primary-care practice in the UK using analysis of data within the VetCompass™ programme.

MATERIALS AND METHODS

Case records from the VetCompass™ programme from primary-care practices in the UK were searched for newly diagnosed lymphoma in dogs within a 1-year period: 2013. Diagnosis was based on clinical records with or without laboratory confirmation. Signalment was evaluated as risk factors for lymphoma diagnosis using multivariable logistic regression.

RESULTS

There were 286 presumed newly diagnosed cases identified during 2013 from 455,553 dogs (overall incidence risk 63 of 100,000 dogs per year) of which 193 (67%) were laboratory confirmed (42 of 100,000 dogs per year). Advanced age, dogs older than 12 years, dogs weighing more than 30 kg and some specific breeds were significantly associated with lymphoma diagnosis. Only 18 dogs (6%) of the population identified were referred to a specialist clinic.

CLINICAL SIGNIFICANCE

This study concurs with others that age, bodyweight and breed are significant risk factors for lymphoma. Results of this study highlight: (1) the low number of dogs with lymphoma that are referred to specialists in the UK and (2) that few dogs undergo immunophenotyping (which can carry prognostic importance), emphasising the importance of epidemiological programmes that evaluate diseases presented to primary-care veterinarians.

Evaluation of serum thymidine kinase 1 activity as a biomarker for treatment effectiveness and prediction of relapse in dogs with non-Hodgkin lymphoma

BACKGROUND

Serum thymidine kinase 1 (sTK1) activity is closely correlated with DNA synthesis.

OBJECTIVES

Evaluate sTK1 activity as a biomarker for treatment response and early detection of relapse in dogs with lymphoma.

ANIMALS

Ninety-seven client-owned dogs with naive or relapsed lymphoma and 23 healthy dogs.

METHODS

Prospective study. Serum TK1 activity measured by refined ELISA-based method (DiviTum assay, Biovica International) before treatment, at clinical response, and every 4 weeks until relapse or last follow-up.

RESULTS

Serum TK1 activity was ≤20 Du/L in 96% (22/23) of healthy dogs. Pretreatment sTK1 activity was >20 Du/L in 88% (85/97) dogs with lymphoma. At clinical response, sTK1 activity was significantly lower in dogs with complete (CR, n = 36) versus partial (PR, n = 29) response (P < .0001). Sensitivity (Se) and specificity (Sp) of sTK1 activity for detecting nonfully responders were 76% and 100%, respectively, with cutoff of 119.5 Du/L (AUC, 0.90; 95%-CI, 0.81-0.98; P < .0001). In dogs with CR, a 5-fold increase in sTK1 activity at a 4-week interval predicted relapse at the subsequent 4-week assessment with a Se 50% and Sp 94% (AUC, 0.72; 95%-CI, 0.55-0.90; P = .02). An increase of sTK1 activity (>2.7-fold value measured at clinical response) predicted relapse at subsequent 4-week assessment with a Se 61% and Sp 88% (AUC, 0.79; 95%-CI, 0.64-0.95; P = .004).

CONCLUSIONS AND CLINICAL IMPORTANCE

Monitoring sTK1 activity could help to detect complete responders and early disease progression in dogs with lymphoma.

Incidence, characteristics and geographical distributions of canine and human non-Hodgkin's lymphoma in the Porto region (North West Portugal)

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.

Demographic risk factors for lymphoma in Australian dogs: 6201 cases

Background

Lymphoma is common in the dog. Studies of population risk factors primarily have been derived from referral institution or insurance data.

Objective

To identify and quantify the host risk factors for lymphoma in a broad population of Australian dogs.

Animals

Data on 6201 client owned dogs were retrieved from a commercial veterinary laboratory, a general practice group and 2 referral hospitals.

Methods

Data collected included breed, sex, and neuter status. A reference population of 640 105 dogs was generated from the referral hospitals and from council registration data. The risk of lymphoma by sex and neuter status was calculated as odds ratios (OR).

Results

The study identified 30 breeds at increased risk of lymphoma, 15 that have not been reported previously, and 26 breeds at decreased risk, 18 that have not been reported previously. Males were over represented compared to females with an OR of 1.1 (95% CI, 1.1–1.2; P < .001). Neutered animals were at higher risk compared to intact animals with an OR of 3.2 (95% CI, 2.9–3.5) which was found in both males (OR, 2.8; 95% CI; 2.5–3.2) and females (OR, 4.4; 95% CI, 3.5–5.1).

Conclusions and Clinical Importance

Breed, sex, and neuter status alter the risk of lymphoma in dogs. These 3 factors must be considered when evaluating lymphoma risk as potential markers of underlying differences in disease etiology. Comparison of breeds at increased and decreased risk could be advantageous when evaluating specific etiological factors.

Breed-associated risks for developing canine lymphoma differ among countries: an European canine lymphoma network study

BACKGROUND

Canine breeds may be considered good animal models for the study of genetic predisposition to cancer, as they represent genetic clusters. From epidemiologic and case collection studies it emerges that some breeds are more likely to develop lymphoma or specific subtypes of lymphoma but available data are variable and geographically inconsistent. This study was born in the context of the European Canine Lymphoma Network with the aim of investigating the breed prevalence of canine lymphoma in different European countries and of investigating possible breed risk of lymphoma overall and/or different lymphoma subtypes.

RESULTS

A total of 1529 canine nodal lymphoma cases and 55,529 control cases from 8 European countries/institutions were retrospectively collected. Odds ratios for lymphoma varied among different countries but Doberman, Rottweiler, boxer and Bernese mountain dogs showed a significant predisposition to lymphoma. In particular, boxers tended to develop T-cell lymphomas (either high- or low-grade) while Rottweilers had a high prevalence of B-cell lymphomas. Labradors were not predisposed to lymphoma overall but tended to develop mainly high-grade T-cell lymphomas. In contrast with previous studies outside of Europe, the European golden retriever population did not show any possible predisposition to lymphoma overall or to specific subtypes such as T-zone lymphoma.

CONCLUSION

Further prospective studies with more precise and consistent subtype identification are needed to confirm our retrospective results and to create the basis for the investigation of possible genes involved in different predispositions.

Breed prevalence of canine lymphoma in South Africa

Lymphoma is a common haematopoietic neoplasm in dogs. Several breeds have been shown to have a predisposition to lymphoma; however, very little information exists regarding the South African dog population. This study assessed whether any breed had increased odds of developing lymphoma compared with others, and also investigated the effects of age, sex and neutering status on disease prevalence. Two study populations and their corresponding reference populations were studied retrospectively. Odds ratios (ORs) for lymphoma in 49 dog breeds, together with their 95% confidence intervals (CI), were calculated. Age effect was assessed by calculating ORs for different age categories in one of the populations. The chi-square test was used to evaluate differences in the prevalence of the various sex and neutering categories in one lymphoma population compared with its reference population. Fourteen breeds had significantly increased odds of developing lymphoma, and one breed had significantly decreased odds (p < 0.050). The median ages of the two lymphoma populations were 6.5 and 8.0 years, with the 6.1-9.0 year category having significantly increased odds of developing lymphoma (OR 1.61, CI 1.2-2.16, p = 0.002). In one of the lymphoma populations, higher proportions of males (p = 0.033) and neutered females (p = 0.006) were found when compared with the reference population. These findings suggest that certain breeds in South Africa have a higher risk of developing lymphoma, and that sex hormones may play a role in lymphoma pathogenesis. The findings may provide useful information for pet owners and veterinarians.

Population characteristics of golden retriever lifetime study enrollees

BACKGROUND

Studying cancer and other diseases poses a problem due to their protracted and multifactorial nature. Prospective studies are useful to investigate chronic disease processes since collection of lifestyle information, exposure data and co-incident health issues are collected before the condition manifests. The Golden Retriever Lifetime Study is one of the first prospective studies following privately-owned dogs throughout life to investigate the incidence and risk factors for disease outcomes, especially cancer.Owners of golden retrievers in the contiguous United States volunteered their dogs in early life. Owners and veterinarians complete online questionnaires about health status and lifestyle; dogs undergo a physical examination and collection of biological samples annually. The data presented summarize the initial study visits and the corresponding questionnaires for 3044 dogs in the cohort.

RESULTS

The median age of dogs at enrollment was 14.0 months (interquartile range (IQR): 8-20 months). Approximately half of the population had undergone gonadectomy by their initial study visit. Medical conditions reported at enrollment consisted primarily of integumentary, gastrointestinal and urinary dysfunction. A large majority of the dogs have a record of having received preventive care (vaccines, parasiticides, flea and heartworm prevention) by the time of the initial study visit. Clinical pathology data were unremarkable.

CONCLUSIONS

This study represents one of the first lifetime observational investigations in veterinary medicine. The population characteristics reported here indicate a healthy cohort of golden retrievers cared for by owners committed to their dogs' health. Data acquired over the study period will provide valuable information about genetic, dietary and environmental risk factors associated with disease in golden retrievers and a framework for future prospective studies in veterinary medicine.

Canine cancer immunotherapy studies: linking mouse and human

Despite recent major clinical breakthroughs in human cancer immunotherapy including the use of checkpoint inhibitors and engineered T cells, important challenges remain, including determining the sub-populations of patients who will respond and who will experience at times significant toxicities. Although advances in cancer immunotherapy depend on preclinical testing, the majority of in-vivo testing currently relies on genetically identical inbred mouse models which, while offering critical insights regarding efficacy and mechanism of action, also vastly underrepresent the heterogeneity and complex interplay of human immune cells and cancers. Additionally, laboratory mice uncommonly develop spontaneous tumors, are housed under specific-pathogen free conditions which markedly impacts immune development, and incompletely model key aspects of the tumor/immune microenvironment. The canine model represents a powerful tool in cancer immunotherapy research as an important link between murine models and human clinical studies. Dogs represent an attractive outbred combination of companion animals that experience spontaneous cancer development in the setting of an intact immune system. This allows for study of complex immune interactions during the course of treatment while also directly addressing long-term efficacy and toxicity of cancer immunotherapies. However, immune dissection requires access to robust and validated immune assays and reagents as well as appropriate numbers for statistical evaluation. Canine studies will need further optimization of these important mechanistic tools for this model to fulfill its promise as a model for immunotherapy. This review aims to discuss the canine model in the context of existing preclinical cancer immunotherapy models to evaluate both its advantages and limitations, as well as highlighting its growth as a powerful tool in the burgeoning field of both human and veterinary immunotherapy.

[Multicentric lymphoma in 411 dogs - an epidemiological study]

OBJECTIVE

To provide an overview of the epidemiology of canine multicentric lymphoma in Germany.

MATERIAL AND METHODS

A total of 411 dogs with multicentric malignant lymphoma were retrospectively analysed regarding breed, age, sex, weight and the number of animals dogs with hypercalcaemic lymphoma and B-/T-immunophenotype, and compared to two reference populations (total own clinic population, n   =   52  142; dogs with health insurance in Germany, n   =   123  423).

RESULTS

In total, 298 (72.5%) of the 411 dogs belonged to 86 different breeds, while 113 (27.5%) dogs were mixed breed. In comparison to both reference populations, a breed predisposition for the American Pitbull Terrier (odds ratio [OR] 5.2 and 18.5), American Staffordshire Terrier (OR 3.3 and 4.6), Briard (OR 5.6 and 9.5), Bullmastiff (OR 7.8 and 5.0), Irish Setter (OR 3.3 and 4.1) and Rottweiler (OR 2.8 and 3.6) was found. Golden Retrievers (n = 22, OR 1.3 and 0.9) and Bernese Mountain Dogs (n = 22, OR 2.4 and 2.0) were frequently affected in absolute numbers, but when compared to the reference populations an OR < 3 was detected. Mean body weight was 30.2 ± 13.7 kg; only 75 (18%) dogs weighed < 15 kg. Amongst the small dogs (< 15 kg), there was a large number of West Highland White Terriers (n = 12). Mean age of the dogs with lymphoma was 7.9 ± 2.7 years. Dogs weighing ≥ 15 kg were significantly (p < 0.001) younger (7.6 ± 2.4 years) compared to dogs weighing < 15 kg (9.3 ± 3.2 years). Dogs with a B-cell immunophenotype (8.5 ± 2.6 years) were significantly older compared to dogs with a T-cell immunophenotype (6.4 ± 1.8 years) (p < 0.001). There was no gender predisposition (54% male, 46% female). Hypercalcaemia as an indicator of T-cell lymphoma was present in 44 (11.4%) of the dogs. A T-cell and B-cell immunophenotype was found in 20.6% and 79.4% of the dogs, respectively.

CLINICAL RELEVANCE

This study confirms previous data about breed predispositions for canine malignant multicentric lymphoma and demonstrates that further breeds are predisposed (Briard, West Highland White Terrier, Irish Setter). Small-breed dogs (< 15 kg BM) appear to be affected with lymphoma at a greater age.

Comparative Analysis of Genome Diversity in Bullmastiff Dogs

Management and preservation of genomic diversity in dog breeds is a major objective for maintaining health. The present study was undertaken to characterise genomic diversity in Bullmastiff dogs using both genealogical and molecular analysis. Genealogical analysis of diversity was conducted using a database consisting of 16,378 Bullmastiff pedigrees from year 1980 to 2013. Additionally, a total of 188 Bullmastiff dogs were genotyped using the 170,000 SNP Illumina CanineHD Beadchip. Genealogical parameters revealed a mean inbreeding coefficient of 0.047; 142 total founders (f); an effective number of founders (fe) of 79; an effective number of ancestors (fa) of 62; and an effective population size of the reference population of 41. Genetic diversity and the degree of genome-wide homogeneity within the breed were also investigated using molecular data. Multiple-locus heterozygosity (MLH) was equal to 0.206; runs of homozygosity (ROH) as proportion of the genome, averaged 16.44%; effective population size was 29.1, with an average inbreeding coefficient of 0.035, all estimated using SNP Data. Fine-scale population structure was analysed using NETVIEW, a population analysis pipeline. Visualisation of the high definition network captured relationships among individuals within and between subpopulations. Effects of unequal founder use, and ancestral inbreeding and selection, were evident. While current levels of Bullmastiff heterozygosity, inbreeding and homozygosity are not unusual, a relatively small effective population size indicates that a breeding strategy to reduce the inbreeding rate may be beneficial.

Complex disease and phenotype mapping in the domestic dog

The domestic dog is becoming an increasingly valuable model species in medical genetics, showing particular promise to advance our understanding of cancer and orthopaedic disease. Here we undertake the largest canine genome-wide association study to date, with a panel of over 4,200 dogs genotyped at 180,000 markers, to accelerate mapping efforts. For complex diseases, we identify loci significantly associated with hip dysplasia, elbow dysplasia, idiopathic epilepsy, lymphoma, mast cell tumour and granulomatous colitis; for morphological traits, we report three novel quantitative trait loci that influence body size and one that influences fur length and shedding. Using simulation studies, we show that modestly larger sample sizes and denser marker sets will be sufficient to identify most moderate- to large-effect complex disease loci. This proposed design will enable efficient mapping of canine complex diseases, most of which have human homologues, using far fewer samples than required in human studies.

The domestic dog is an important model organism for our understanding of cancer and other diseases. Here the authors conduct a genome-wide association study across multiple breeds and identify novel loci significantly associated with several complex diseases and morphological traits.

The animal-dependent risk factors in canine T-cell lymphomas

Malignant lymphomas are one of the most common malignancies occurring in dogs; among them T-cell tumours are less commonly recognized. Recently, many authors have recommended cytology as a sufficient diagnostic method for canine lymphomas, especially if supported by immunocytochemistry or flow cytometry. The aim of the study was to characterize animal-dependent risk factors in canine T-cell lymphomas (TCLs) in Poland, including specific cytological subtypes. Determination of the type and subtype of the tumour was made based on the updated Kiel cytological classification adopted for dogs as previously described. Two breeds turned out predisposed to TCL (dog de Bordeaux and Boxer) while no predisposition to B-cell lymphoma could be evidenced. Dogs with low-grade lymphoma were significantly older than those with high-grade lymphoma.

Man's best friend: what can pet dogs teach us about non-Hodgkin's lymphoma?

Animal models are essential for understanding lymphoma biology and testing new treatments prior to human studies. Spontaneously arising lymphomas in pet dogs represent an underutilized resource that could be used to complement current mouse lymphoma models, which do not adequately represent all aspects of the human disease. Canine lymphoma resembles human lymphoma in many important ways, including characteristic translocations and molecular abnormalities and similar therapeutic responses to chemotherapy, radiation, and newer targeted therapies (e.g. ibrutinib). Given the large number of pet dogs and high incidence of lymphoma, particularly in susceptible breeds, dogs represent a largely untapped resource for advancing the understanding and treatment of human lymphoma. This review highlights similarities in molecular biology, diagnosis, treatment, and outcomes between human and canine lymphoma. It also describes resources that are currently available to study canine lymphoma, advantages to be gained by exploiting the genetic breed structure in dogs, and current and future challenges and opportunities to take full advantage of this resource for lymphoma studies.

Breed, gender and age pattern of diagnosis for veterinary care in insured dogs in Japan during fiscal year 2010

We calculated the annual prevalence of diseases of 18 diagnostic categories in the insured dog population in Japan, using data from 299,555 dogs insured between April 2010 and March 2011. The prevalence was highest for dermatological disorders (22.6% for females and 23.3% for males), followed by otic diseases (16.4% for females and 17.2% for males) and digestive system disorders (15.7% for females and 16.4% for males). The prevalence of cardiovascular, urinary, neoplasia and endocrine disorders, increased with age; infectious diseases and injuries showed a high prevalence at young ages, and the prevalence of musculoskeletal and respiratory disorders showed a bimodal peak at young and old ages. A large variation in prevalence was observed between breeds for dermatological, otic, digestive, ophthalmological and cardiovascular disorders.

Approaches to canine health surveillance

Effective canine health surveillance systems can be used to monitor disease in the general population, prioritise disorders for strategic control and focus clinical research, and to evaluate the success of these measures. The key attributes for optimal data collection systems that support canine disease surveillance are representativeness of the general population, validity of disorder data and sustainability. Limitations in these areas present as selection bias, misclassification bias and discontinuation of the system respectively. Canine health data sources are reviewed to identify their strengths and weaknesses for supporting effective canine health surveillance. Insurance data benefit from large and well-defined denominator populations but are limited by selection bias relating to the clinical events claimed and animals covered. Veterinary referral clinical data offer good reliability for diagnoses but are limited by referral bias for the disorders and animals included. Primary-care practice data have the advantage of excellent representation of the general dog population and recording at the point of care by veterinary professionals but may encounter misclassification problems and technical difficulties related to management and analysis of large datasets. Questionnaire surveys offer speed and low cost but may suffer from low response rates, poor data validation, recall bias and ill-defined denominator population information. Canine health scheme data benefit from well-characterised disorder and animal data but reflect selection bias during the voluntary submissions process. Formal UK passive surveillance systems are limited by chronic under-reporting and selection bias. It is concluded that active collection systems using secondary health data provide the optimal resource for canine health surveillance.

Canine lymphoma as a comparative model for human non-Hodgkin lymphoma: recent progress and applications

The term "lymphoma" describes a heterogeneous group of disorders involving monoclonal proliferation of malignant lymphocytes. As a group, lymphomas are among the most common tumors of dogs. Yet our enumeration and understanding of the many subtypes of lymphoma have been relatively slow, perhaps in part because for many years lymphoma was treated as a singular entity rather than a group of distinct diseases. The recognition that the full spectrum of lymphoid malignancies seen in humans also occurs in dogs, and that these tumors retain not only morphologic similarities and biological behavior but also synonymous driver molecular abnormalities, sets an ideal stage for dual-purpose research that can accelerate progress for these diseases in both species. Specifically, dogs represent exceptional models for defining causality, understanding progression, and developing new treatments for lymphoma in comparatively brief windows of time. Unique advantages of canine models include (1) spontaneous disease occurring without an isogenic background or genetic engineering; (2) chronology of disease adapted to lifespan, (3) shared environment and societal status that allows dogs to be treated as "patients," while at the same time being able to ethically explore translational innovations that are not possible in human subjects; and (4) organization of dogs into breeds with relatively homogeneous genetic backgrounds and distinct predisposition for lymphomas. Here, we will review recent studies describing intrinsic and extrinsic factors that contribute to the pathogenesis of canine and human lymphomas, as well as newly developed tools that will enhance the fidelity of these models to improve diagnosis and develop new treatments.

Estimated incidence rate and distribution of tumours in 4,653 cases of archival submissions derived from the Dutch golden retriever population

Background

A genetic predisposition for certain tumour types has been proven for some dog breeds. Some studies have suggested that this may also be true for the Golden retriever breed. The present study aimed to examine a possible existence of a tumour (type) predisposition in the Dutch population of Golden retrievers by evaluating annual estimated incidence rates compared to incidence rates from previous publications. A second aim was to evaluate whether incidences of various tumours differed as related to the diagnostic method chosen, being either cytology or histology.

Results

Tumours submitted to Utrecht University during the period 1998–2004 diagnosed either by means of cytology (n = 2,529) or histology (n = 2,124), were related to an average annual Dutch kennel club population of 29,304 Golden retrievers.

Combining individual tumours from both the cytological and the histopathological data-set resulted in an annual estimated incidence rate of 2,242 for 100,000 dog-years at risk regarding tumour development in general.

The most common cytological tumor diagnoses were ‘fat, possibly lipoma’ (35%), mast cell tumour (21%) and non-Hodgkin lymphoma (10%). The most commonly diagnosed tumours by histology were mast cell tumour (26%), soft tissue sarcomas (11%) and melanoma (8%). Both the cytological and histopathological data-sets, showed variation; in patient age distribution, age of onset and incidence of various tumours.

Conclusion

Comparing our data with previous reports in non-breed-specified dog populations, the Golden retriever breed shows an increased risk for the development of tumours in general, as well as an increased risk for the development of specific tumour types, including the group of soft tissue sarcomas. Variations in age, location and incidence of various tumours were observed between the two data-sets, indicating a selection bias for diagnostic procedure.

Breed predispositions in canine mast cell tumour: a single centre experience in the United Kingdom

Genetic factors play a major role in carcinogenesis. Many breeds have been reported to be predisposed to mast cell tumour (MCT) development using various methods and diverse control populations. A database of 222 dogs with MCT seen at a UK university referral hospital was compared to three control populations, namely, an insured population of UK dogs, registrations with the UK Kennel Club and other dogs seen through the same hospital. Odds ratios were calculated for each breed. Boxers, Labradors, Golden Retrievers and Staffordshire Bull Terriers appeared predisposed to MCT development. English Springer Spaniels, English Cocker Spaniels, German Shepherd Dogs, West Highland White Terriers and Cavalier King Charles Spaniels were underrepresented.

Breed-predispositions to cancer in pedigree dogs

Cancer is a common problem in dogs and although all breeds of dog and crossbred dogs may be affected, it is notable that some breeds of pedigree dogs appear to be at increased risk of certain types of cancer suggesting underlying genetic predisposition to cancer susceptibility. Although the aetiology of most cancers is likely to be multifactorial, the limited genetic diversity seen in purebred dogs facilitates genetic linkage or association studies on relatively small populations as compared to humans, and by using newly developed resources, genome-wide association studies in dog breeds are proving to be a powerful tool for unravelling complex disorders. This paper will review the literature on canine breed susceptibility to histiocytic sarcoma, osteosarcoma, haemangiosarcoma, mast cell tumours, lymphoma, melanoma, and mammary tumours including the recent advances in knowledge through molecular genetic, cytogenetic, and genome wide association studies.

Quantification of plasma DNA as a prognostic indicator in canine lymphoid neoplasia

Dogs have a similar incidence of spontaneous cancers as people, and a noninvasive test to monitor disease status in dogs would be of great value. Humans with cancer often have increased levels of cell-free circulating DNA in their plasma, which has shown promise for diagnosis, prognosis and detection of residual disease. We hypothesized that dogs with cancer have increased circulating DNA compared with healthy dogs or dogs with non-neoplastic diseases. Plasma DNA was measured in 40 healthy dogs, 20 dogs with non-neoplastic diseases and 80 dogs with cancer. The reference interval for plasma DNA in healthy dogs was 1-15 ng mL(-1). Dogs with lymphoma and lymphoid leukaemia had significantly higher concentrations (range: 0-91 ng mL(-1), P < 0.0001). Antigen receptor rearrangement assays suggest that plasma DNA had the same clonality as the primary lymphoid tumours. Dogs with lymphoid neoplasia and plasma DNA >25 ng mL(-1) had shorter remission times than those with < 25 ng mL(-1) (P = 0.0116). In contrast to humans, where increased plasma DNA is seen in many diseases, dogs with nonlymphoid malignancies and non-neoplastic diseases had plasma DNA concentrations similar to healthy dogs. This study shows that a portion of dogs with lymphoid neoplasia have increased tumour-derived plasma DNA, which serves as a negative prognostic indicator.

T-cell-derived malignant lymphoma in the boxer breed

The boxer breed of dog is at high risk for a variety of neoplasms including lymphoma. In this observational study, tissue sections from boxer dogs with lymphoma were immunostained for T and B lymphocyte distinction, and the results compared with similar studies carried out on lymphoma tissues from temporally selected cohorts of golden retriever and rottweiler dogs. The frequency of T-cell lymphomas was significantly (P < 0.001 for all comparisons) higher in the boxers than in the rottweilers or golden retrievers. We are unaware of other reports linking immunotype of canine lymphoma with breed; whether other brachycephalic breeds of dogs have a similar preponderance of T-cell lymphoma awaits further study.

Oncolytic gene therapy for canine cancers: teaching old dog viruses new tricks

The use of viruses to treat cancer has been studied for decades. With the advancement of molecular biology, viruses have been modified and genetically engineered to optimize their ability to target cancer cells. Canine viruses, such as distemper virus and adenovirus, are being exploited for the treatment of canine cancer as the dog has proven to be a good comparative model for human cancer research and proof of concept investigations. In this review, we introduce the concept of oncolytic viruses and describe some of the preliminary attempts to use oncolytic viruses for the treatment of canine cancer.

Insurance data for research in companion animals: benefits and limitations

The primary aim of this article is to review the use of animal health insurance data in the scientific literature, especially in regard to morbidity or mortality in companion animals and horses. Methods and results were compared among studies on similar health conditions from different nations and years. A further objective was to critically evaluate benefits and limitations of such databases, to suggest ways to maximize their utility and to discuss the future use of animal insurance data for research purposes. Examples of studies on morbidity, mortality and survival estimates in dogs and horses, as well as neoplasia in dogs, are discussed.We conclude that insurance data can and should be used for research purposes in companion animals and horses. Insurance data have been successfully used, e.g. to quantify certain features that may have been hitherto assumed, but unmeasured. Validation of insurance databases is necessary if they are to be used in research. This must include the description of the insured population and an evaluation of the extent to which it represents the source population. Data content and accuracy must be determined over time, including the accuracy/consistency of diagnostic information. Readers must be cautioned as to limitations of the databases and, as always, critically appraise findings and synthesize information with other research. Similar findings from different study designs provide stronger evidence than a sole report. Insurance data can highlight common, expensive and severe conditions that may not be evident from teaching hospital case loads but may be significant burdens on the health of a population.

Animal tumour registry of two provinces in northern Italy: incidence of spontaneous tumours in dogs and cats

BACKGROUND

Cancer is a major cause of death in domestic animals. Furthermore, many forms of pet neoplasm resemble that of their human counterparts in biologic behaviour, pathologic expression, and recognised risk factors.In April 2005, a pilot project was activated so as to establish a dog and cat tumour registry living in the Venice and Vicenza provinces (Veneto Region, north-eastern Italy), with the aim of estimating the incidence of spontaneous tumours.

RESULTS

Through a telephone survey, the estimates of canine and feline populations of the catchment area turned out to be of 296,318 (CI +/- 30,201) and 214,683 (CI +/- 21,755) subjects, respectively. During the first three years, overall 2,509 canine and 494 feline cases of neoplasia were diagnosed. In dogs, the estimated annual incidence rate (IR) per 100,000 dogs for all tumours was 282 in all the catchment area, whereas in cats the IR was much lower (IR = 77). Malignant and benign tumours were equally distributed in male and female dogs, whereas cats had a 4.6-fold higher incidence of malignant tumours than benign. In both dogs and cats, purebreds had an almost 2-fold higher incidence of malignant tumours than mixed breeds. Tumour incidence increased with age in both dog and cat populations.

CONCLUSION

This study has provided estimates of incidence of spontaneous neoplasm in companion animals. Further attempts will be made to increase the accuracy in the population size assessment and to ascertain the real gap with the official regional canine demographic registry. Veterinary practitioners may also benefit from the tumour registry insofar they may obtain data for specific breeds, age groups or geographical areas.