Epidemiologic studies of risk factors for cancer in pet dogs

Predicting health outcomes in dogs using insurance claims data

In this paper we propose a machine learning-based approach to predict a multitude of insurance claim categories related to canine diseases. We introduce several machine learning approaches that are evaluated on a pet insurance dataset consisting of 785,565 dogs from the US and Canada whose insurance claims have been recorded over 17 years. 270,203 dogs with a long insurance tenure were used to train a model while the inference is applicable to all dogs in the dataset. Through this analysis we demonstrate that with this richness of data, supported by the right feature engineering, and machine learning approaches, 45 disease categories can be predicted with high accuracy.

ICRP PUBLICATION 153 Approved by the Commission in September 2022

Veterinary use of radiation in the diagnosis, management, and treatment of disease has expanded and diversified, as have the corresponding radiological protection concerns. Radiological exposure of personnel involved in veterinary procedures and, where applicable, members of the public providing assistance (e.g. owners or handlers) has always been included within the system of radiological protection. Veterinary practice is now addressed explicitly as the modern complexities associated with this practice warrant dedicated consideration, and there is a need to clarify and strengthen the application of radiological protection principles in this area. The Commission recommends that the system of radiological protection should be applied in veterinary practice principally for the protection of humans, but with explicit attention to the protection of exposed animals. Additionally, consideration should be given to the risk of potential contamination of the environment associated with applications of nuclear medicine in veterinary practice. This publication focuses primarily on justification and optimisation in veterinary practice, and sets the scene for more detailed guidance to follow in future Recommendations. It is intended for a wide-ranging audience, including radiological protection professionals, veterinary staff, students, education and training providers, and members of the public, as an introduction to radiological protection in veterinary practice.© 2022 ICRP. Published by SAGE.

Healthy, Active Aging for People and Dogs

Dogs act as companions who provide us with emotional and physical support. Their shorter lifespans compel us to learn about the challenges and gifts of caring for older individuals. Our companion dogs can be exemplars of healthy or unhealthy aging, and sentinels of environmental factors that might increase or decrease our own healthy lifespan. In recent years, the field of aging has emphasized not just lifespan, but healthspan—the period of healthy, active lifespan. This focus on healthy, active aging is reflected in the World Health Organization's current focus on healthy aging for the next decade and the 2016 Healthy Aging in Action initiative in the US. This paper explores the current research into aging in both people and companion dogs, and in particular, how the relationship between older adults and dogs impacts healthy, active aging for both parties. The human-dog relationship faces many challenges as dogs, and people, age. We discuss potential solutions to these challenges, including suggestions for ways to continue contact with dogs if dog ownership is no longer possible for an older person. Future research directions are outlined in order to encourage the building of a stronger evidence base for the role of dogs in the lives of older adults.

Translational oncotargets for immunotherapy: From pet dogs to humans

Preclinical studies in rodent models have been a pivotal role in human clinical research, but many of them fail in the translational process. Spontaneous tumors in pet dogs have the potential to bridge the gap between preclinical models and human clinical trials. Their natural occurrence in an immunocompetent system overcome the limitations of preclinical rodent models. Due to its reasonable cellular, molecular, and genetic homology to humans, the pet dog represents a valuable model to accelerate the translation of preclinical studies to clinical trials in humans, actually with benefits for both species. Moreover, their unique genetic features of breeding and breed-related mutations have contributed to assess and optimize therapeutics in individuals with different genetic backgrounds. This review aims to outline four main immunotherapy approaches - cancer vaccines, adaptive T-cell transfer, antibodies, and cytokines -, under research in veterinary medicine and how they can serve the clinical application crosstalk with humans.

Epigenetic Mechanisms in Canine Cancer

A plethora of data has highlighted the role of epigenetics in the development of cancer. Initiation and progression of different cancer types are associated with a variety of changes of epigenetic mechanisms, including aberrant DNA methylation, histone modifications, and miRNA expression. At the same time, advances in the available epigenetic tools allow to investigate and reverse these epigenetic changes and form the basis for the development of anticancer drugs in human oncology. Although human and canine cancer shares several common features, only recently that studies emerged investigating the epigenetic landscape in canine cancer and applying epigenetic modulators to canine cancer. This review focuses on the existing studies involving epigenetic changes in different types of canine cancer and the use of small-molecule inhibitors in canine cancer cells.

Safety studies and viral shedding of intramuscular administration of oncolytic vaccinia virus TG6002 in healthy beagle dogs

BACKGROUND

Cancer is a leading cause of mortality for both humans and dogs. As spontaneous canine cancers appear to be relevant models of human cancers, developing new therapeutic approaches could benefit both species. Oncolytic virotherapy is a promising therapeutic approach in cancer treatment. TG6002 is a recombinant oncolytic vaccinia virus deleted in the thymidine kinase and ribonucleotide reductase genes and armed with the suicide gene FCU1 that encodes a protein which catalyses the conversion of the non-toxic 5-fluorocytosine into the toxic metabolite 5-fluorouracil. Previous studies have shown the ability of TG6002 to infect and replicate in canine tumor cell lines, and demonstrated its oncolytic potency in cell lines, xenograft models and canine mammary adenocarcinoma explants. Moreover, 5-fluorouracil synthesis has been confirmed in fresh canine mammary adenocarcinoma explants infected with TG6002 with 5-fluorocytosine. This study aims at assessing the safety profile and viral shedding after unique or repeated intramuscular injections of TG6002 in seven healthy Beagle dogs.

RESULTS

Repeated intramuscular administrations of TG6002 at the dose of 5 × 10⁷ PFU/kg resulted in no clinical or biological adverse effects. Residual TG6002 in blood, saliva, urine and feces of treated dogs was not detected by infectious titer assay nor by qPCR, ensuring the safety of the virus in the dogs and their environment.

CONCLUSIONS

These results establish the good tolerability of TG6002 in healthy dogs with undetectable viral shedding after multiple injections. This study supports the initiation of further studies in canine cancer patients to evaluate the oncolytic potential of TG6002 and provides critical data for clinical development of TG6002 as a human cancer therapy.

Environmental Toxic Exposures Using Companion Animals as an Indicator of Human Toxicity: A Case Report and Discussion

BACKGROUND

Hundreds of years ago, humans realized that animals could be used as surrogate indicators of toxic environmental exposures, as a tool to measure risk to human health. The classic example is coal miners bringing canaries into coal mines. The respiratory rate and metabolism of the animal resulted in toxic signs of injurious gases in the environment before humans were injured. Occasionally, modern diagnosis of cryptic toxic exposures can be aided by the discovery of such features in the history.

OBJECTIVES

We introduce this review using a case of inhalational mercury toxicity involving humans and companion animals-household dogs and cats. The death of exposed pets prior to the mounting of symptoms in the exposed humans was advance warning of the near-fatal presentation to come. Our objective was to review and characterize the state of the literature on companion animals as sentinel species.

DISCUSSION

We reviewed 748 articles, which resulted in 25 selected for inclusion in this narrative review. We detail examples of companion animals (household dogs, cats, and birds) affected by toxic exposures in acute and chronic ways-acting as harbingers of impending human toxicity in acute or chronic settings. Mercury, lead, Teflon, herbicide, and asbestos exposures present with predictable signs and symptoms in companion animals prior to presenting in humans. Identifying the toxidrome in a companion animal allows for subclinical identification of exposure and consequences in the human that permits early treatment and intervention.

CONCLUSIONS

Companion animals, when similarly exposed to toxic substances as humans regarding route, dose, and chronicity often mount symptoms and signs in advance of humans. This phenomenon allows the clinician to identify occult exposure, test, and treat while human disease is mild or still subclinical.

Sentinel species for biomonitoring and biosurveillance of environmental heavy metals in Nigeria

Nigeria receives copious annual precipitation to nourish its forests and agriculture, it has an extensive river drainage system, and it possesses valuable mineral deposits that stimulate both commercial and artisan mining activities. The combination of these features complicates Nigeria's efforts to produce adequate amounts of healthy foods to support its population. Toxic heavy metals like lead, cadmium, and mercury, and toxic metalloids such as arsenic, are also present in its mineral deposits and they migrate gradually into the soil and water of Nigeria by natural means. However, mining activities can liberate higher levels of toxic metals, which adversely affect Nigerian ecosystems and its food chains. Thus, environmental pollution due to anthropogenic activities is a major public health concern in Nigeria. This review covers the importance of native Nigerian and African wild and cultivated plants along with livestock and wild animals as sentinel species to evaluate heavy metals as environmental stressors and the use of sentinel species for food safety monitoring and for predicting potential risks to human health.

Environmental geochemistry and cancer: a pertinent global health problem requiring interdisciplinary collaboration

Primary prevention is a key strategy to reducing the global burden of cancer, a disease responsible for ~ 9.6 million deaths per year and predicted to top 13 million by 2030. The role of environmental geochemistry in the aetiology of many cancers-as well as other non-communicable diseases-should not be understated, particularly in low- and middle-income countries where 70% of global cancer deaths occur and reliance on local geochemistry for drinking water and subsistence crops is still widespread. This article is an expansion of a series of presentations and discussions held at the 34th International Conference of the Society for Environmental Geochemistry and Health in Livingstone, Zambia, on the value of effective collaborations between environmental geochemists and cancer epidemiologists. Key technical aspects of each field are presented, in addition to a case study of the extraordinarily high incidence rates of oesophageal cancer in the East African Rift Valley, which may have a geochemical contribution. The potential merit of veterinary studies for investigating common geochemical risk factors between human and animal disease is also highlighted.

Viral Pathogenesis, Recombinant Vaccines, and Oncolytic Virotherapy: Applications of the Canine Distemper Virus Reverse Genetics System

Canine distemper virus (CDV) is a highly contagious pathogen transmissible to a broad range of terrestrial and aquatic carnivores. Despite the availability of attenuated vaccines against CDV, the virus remains responsible for outbreaks of canine distemper (CD) with significant morbidity and mortality in domesticated and wild carnivores worldwide. CDV uses the signaling lymphocytic activation molecule (SLAM, or CD150) and nectin-4 (PVRL4) as entry receptors, well-known tumor-associated markers for several lymphadenomas and adenocarcinomas, which are also responsible for the lysis of tumor cells and apparent tumor regression. Thus, CDV vaccine strains have emerged as a promising platform of oncolytic viruses for use in animal cancer therapy. Recent advances have revealed that use of the CDV reverse genetic system (RGS) has helped increase the understanding of viral pathogenesis and explore the development of recombinant CDV vaccines. In addition, genetic engineering of CDV based on RGS approaches also has the potential of enhancing oncolytic activity and selectively targeting tumors. Here, we reviewed the host tropism and pathogenesis of CDV, and current development of recombinant CDV-based vaccines as well as their use as oncolytic viruses against cancers.

Predictive modeling for cancer drug discovery using canine models

INTRODUCTION

Rodent models of cancer lack many features associated with the disease in humans. Because dogs closely share an environment with humans, as well as comparable pathophysiology of cancer, they represent a powerful model with which to study novel approaches to cancer treatment.

AREAS COVERED

The authors summarize the weaknesses of rodent models of cancer and the ongoing need for better animal models with which to study potential therapeutic approaches. The homology of cancer in dogs and humans is described, along with examples specific to several common cancer types.

EXPERT OPINION

Laboratory mice and rats will continue to play a central role in cancer research; however, because of a variety of limitations, pet dogs with spontaneous cancer offer unique opportunities for research and should be included in the preclinical development of therapeutic compounds. Environmental homology between dogs and humans, along with biological and molecular similarities present circumstances that strengthen the translational rigor of studies conducted using canine patients. Progress will depend on a sufficient number of dogs to be diagnosed with cancer and available for use in studies; and essential to this will be the availability of enhanced resources for diagnosis of cancer in canine patients and reliable coordination between research scientists, veterinarians, and physicians.

Glutathione S-transferase theta genotypes and environmental exposures in the risk of canine transitional cell carcinoma

Introduction

Transitional cell carcinoma (TCC) in humans is associated with environmental exposures and variants in glutathione S‐transferase (GST) genes. Scottish Terriers have a high breed risk for TCC, but the relationship between genetic and environmental risk in dogs is not fully understood.

Hypotheses

Scottish Terriers have a higher frequency of GST‐theta variants compared to lower risk breeds. Dogs with TCC of any breed have a higher frequency of GST‐theta variants along with higher environmental exposures, compared to controls.

Animals

One hundred and five Scottish Terriers and 68 controls from lower risk breeds; 69 dogs of various breeds with TCC, and 72 breed‐ and sex‐matched unaffected geriatric dogs.

Methods

In this prospective case‐control study, dogs were genotyped for 3 canine GST‐theta variants: GSTT1 I2+28 G>A, a GSTT1 3′UTR haplotype, and GSTT5 Asp129_Gln130del. Owners of dogs with TCC and unaffected geriatric controls completed a household environmental questionnaire.

Results

The GSTT1 3′UTR haplotype and GSTT5 Asp129_Gln130del variants were significantly underrepresented in Scottish Terriers (minor allele frequency [MAF] = 0.000 for both), compared to dogs from lower risk breeds (MAF = 0.108 and 0.100; P ≤ .0002). Dogs with TCC did not differ from unaffected geriatric controls across the 3 investigated loci. Transitional cell carcinoma was associated with household insecticide use (odds ratio [OR] = 4.28, 95% confidence interval [CI] = 1.44‐12.33, P = .02), and was negatively associated with proximity to a farm (OR = 0.49, 95% CI = 0.25‐0.99, P = .04).

Conclusions and Clinical Importance

Low‐activity GST‐theta loci are unlikely contributors to TCC risk in dogs. Increased risk is associated with household insecticide use, and possibly with less rural households.

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.

Acute radiotherapy toxicity in 57 dogs with gross and microscopic mast cell tumours

Mast cell tumours (MCTs) are commonly treated with radiation therapy, most often in a microscopic disease setting. Poorer outcomes are expected in patients with gross disease, and irradiation of gross disease may be associated with greater toxicity. The aim of this study was to compare acute radiation adverse events (AE) in dogs with gross and microscopic MCTs receiving radiotherapy. Fifty-seven dogs were included, 28 with gross disease and 29 with microscopic. In order to assess mucosal and skin toxicity, patients were assigned to 2 groups: head (29 patients, 14 patients with gross and 15 microscopic) and other sites (28 patients, 14 each). All were treated with external beam radiotherapy, and toxicity assessed at the end of treatment and 10 to 14 days later (first recheck). All patients developed some acute radiation toxicity by the end of the course. However, there was no difference in the severity of toxicity between gross and microscopic disease in either site group at either time point. The only variable associated with an increased frequency of grade 2 or 3 toxicity at the first recheck was the use of prednisolone prior to radiotherapy (P = .05). No other factors were identified which were associated with increased toxicity. For the head group, the site of highest grade toxicity was mucosa or, if included in the field, nasal planum, which was often more severely affected than the mucosa. No significant late toxicity was identified. Two dogs developed acute haematemesis during the radiotherapy course, but both completed the course without further events.

Cellular effects of a turmeric root and rosemary leaf extract on canine neoplastic cell lines

BACKGROUND

The use of nutraceuticals is gaining in popularity in human and canine oncology with a relatively limited understanding of the effects in the vastly different tumor types seen in canine oncology. We have previously shown that turmeric root (TE) and rosemary leaf (RE) extracts can work synergistically to reduce neoplastic cell growth, but the mechanisms are poorly understood and require further elucidation.

RESULTS

Three different canine cell lines (C2 mastocytoma, and CMT-12 mammary carcinoma, D17 osteosarcoma) were treated with 6.3 μg mL^-1 extract individually, or 3.1 μg mL^-1 of each extract in combination based on studies showing synergy of these two extracts. Apoptosis, antioxidant effects, cellular accumulation of curcumin, and perturbation of signaling pathways were assessed. The TE + RE combination treatment resulted in Caspase 3/7 activation and apoptosis in all cell lines, beyond the effects of TE alone with the CMT-12 cell line being most susceptible. Both extracts had antioxidant effects with RE reducing reactive oxygen species (ROS) by 40-50% and TE reducing ROS by 80-90%. In addition RE treatment enhanced the c-jun N-terminal kinase (JNK) activity in the C2 cell line and TE + RE exposure increased activated JNK by 4-5 times in the CMT-12 cell line. Upon further examination, it was found that RE treatment caused a significant increase in the cellular accumulation of curcumin by approximately 30% in the C2 and D17 cell lines, and by 4.8-fold in the CMT-12 cell line. This increase in intracellular curcumin levels may play a role in the synergy exhibited when using TE and RE in combination.

CONCLUSIONS

The use of RE in combination with TE induces a synergistic response to induce apoptosis which is better than either extract alone. This appears to be related to a variable increased TE uptake in cells and activation of pathways involved in the apoptotic response.

Hair nicotine concentration measurement in cats and its relationship to owner-reported environmental tobacco smoke exposure

OBJECTIVES

To investigate the association between hair nicotine concentration in cats and owner-reported exposure to environmental tobacco smoke.

MATERIALS AND METHODS

Owner questionnaires documented exposure. Nicotine was extracted from hair by sonification in methanol followed by hydrophilic interaction chromatography with mass spectrometry. Relationships between hair nicotine concentration and owner-reported exposure were examined using hypothesis-testing statistics and receiver operating characteristic curve analysis.

RESULTS

The hair nicotine concentration of reportedly exposed cats was significantly higher than unexposed cats and groups of cats with different levels of exposure had significantly different median hair nicotine concentrations corresponding to exposure. A hair nicotine concentration of 0·1 ng/mg had a specificity of 98% (95% confidence interval: 83 to 100) and a sensitivity of 69% (95% confidence interval: 54 to 84) for detecting environmental tobacco smoke exposure. Outdoors access, coat colour, urban or rural environment and length of time living with the owner were not obviously associated with hair nicotine concentration.

CLINICAL SIGNIFICANCE

Feline hair nicotine concentration appears strongly associated with owner-reported environmental tobacco smoke exposure. Feline hair nicotine concentration could therefore be used as a biomarker for tobacco smoke exposure, allowing future studies to assess whether exposed cats have an increased risk of specific diseases.

Estimating canine cancer incidence: findings from a population-based tumour registry in northwestern Italy

Background

Canine cancer registry data can be put to good use in epidemiological studies. Quantitative comparison of tumour types may reveal unusual cancer frequencies, providing directions for research and generation of hypotheses of cancer causation in a specific area, and suggest leads for identifying risk factors. Here we report canine cancer incidence rates calculated from a population-based registry in an area without any known specific environmental hazard.

Results

In its 90 months of operation from 2001 to 2008 (the observation period in this study), the population-based Piedmont Canine Cancer Registry collected data on 1175 tumours confirmed by histopathological diagnosis. The incidence rate was 804 per 100,000 dog-years for malignant tumours and 897 per 100,000 dog-years for benign tumours. Higher rates for all cancers were observed in purebred dogs, particularly in Yorkshire terrier and Boxer. The most prevalent malignant neoplasms were cutaneous mastocytoma and hemangiopericytoma, and mammary gland complex carcinoma and simplex carcinoma.

Conclusions

The Piedmont canine cancer registry is one of few of its kind whose operations have been consistently supported by long-term public funding. The registry-based cancer incidence rates were estimated with particular attention to the validity of data collection, thus minimizing the potential for bias. The findings on cancer incidence rates may provide a reliable reference for comparison studies. Researches conducted on dogs, used as sentinels for community exposure to environmental carcinogens, can be useful to detect excess risks in the incidence of malignant tumours in the human population.

Correlation of neuter status and expression of heritable disorders

BACKGROUND

Gonadectomy, or neutering, is a very common surgery for dogs having many positive effects on behavior, health, and longevity. There are also certain risks associated with neutering including the development of orthopedic conditions, cognitive decline, and a predisposition to some neoplasias. This study was designed specifically to identify if a correlation exists between neuter status and inherited conditions in a large aggregate cohort of dogs representing many different breeds.

RESULTS

Neutered dogs were at less risk for early and congenital conditions (aortic stenosis, early onset cataracts, mitral valve disease, patent ductus arteriosus, portosystemic shunt, and ventricular septal defect) than intact dogs. Neutering was also associated with reduced risk of dilated cardiomyopathy and gastric dilatation volvulus in males. Neutering was significantly associated with an increased risk for males and females for cancers (hemangiosarcoma, hyperadrenocorticism, lymphoma, mast cell tumor, and osteosarcoma), ruptured anterior cruciate ligament and epilepsy. Intervertebral disk disease was associated with increased risk in females only. For elbow dysplasia, hip dysplasia, lens luxation, and patellar luxation neutering had no significant effect on the risk for those conditions. Neutering was associated with a reduced risk of vehicular injury, a condition chosen as a control.

CONCLUSIONS

In this retrospective study, several conditions showed an increased risk associated with neutering whereas other conditions were less likely to be expressed in neutered dogs. The complexity of the interactions between neutering and inherited conditions underscores the need for reflective consultation between the client and the clinician when considering neutering. The convenience and advantages of neutering dogs that will not be included in a breeding program must be weighed against possible risk associated with neutering.

Why man's best friend, the dog, could also benefit from an anti-HER-2 vaccine

Human epidermal growth factor receptor-2 (HER-2) is a well-established target for anticancer anticancerprecision medicine in humans. A HER-2 homologue with 92% amino acid identity has been described in canine mammary tumors, which whichis termed here as ‘dog epidermal growth factor receptor-2 (DER-2)’, with similar biological implications as those in human breast cancer. Both antigens can principally be immunologically targeted by anti-HER-2 antibodies, such as trastuzumab; however, the in vivo application applicationof humanized antibodies to other species would lead to specific hypersensitivity reactions. Therefore, HER-2 mimotope vaccines that actively induce autologous trastuzumab-like immunoglobulins represent a novel and economic treatment option to overcome species-specific limitations. Thus, the present review proposes the implementation of clinical trials with HER-2 vaccines in canine cancer model modelpatients with spontaneous DER-2 positive mammary gland carcinomas in order to assess their safety and efficacy. This approach would not only pave the way into the veterinary oncology market, but would also similarly generate robust data for human trials and facilitate the testing of novel combinatorial treatments.

Effects and synergy of feed ingredients on canine neoplastic cell proliferation

BACKGROUND

Adjunctive use of nutraceuticals in human cancer has shown promise, but little work has been done in canine neoplasia. Previous human research has shown that polyphenols and carotenoids can target multiple pathways in vitro and in vivo. These compounds could synergize or antagonize with currently used chemotherapies, either increasing or decreasing the effectiveness of these drugs. Considering the routine and well controlled feeding practices of most dogs, the use of nutraceuticals incorporated into pet food is attractive, pending proof that the extracts are able to improve remission rates. The aim of this study was to examine five feed ingredients for antiproliferative effects, as well as the interaction with toceranib phosphate and doxorubicin hydrochloride, when treating canine neoplastic cell lines in vitro.

RESULTS

Screening using MTT proliferation assays showed that green tea, turmeric, and rosemary extracts were the most effective. Turmeric extract (TE) was the most potent and exhibited synergy with a rosemary extract (RE) at concentrations from 1 to 25 μg mL(-1). This combination had an additive or synergistic effect with chemotherapeutic agents at selected concentrations within each cell line. No significant effects on cell viability were observed when the combination therapy was used with normal primary cells.

CONCLUSIONS

The use of turmeric and rosemary extracts in combination may be worthwhile to investigate in the pre-clinical and clinical neoplastic considering there are no negative effects on traditional chemotherapy treatment. Further studies into the pharmacokinetics and mechanisms of action of these extracts should be investigated.

Establishment and Characterization of New Canine and Feline Osteosarcoma Primary Cell Lines

Osteosarcomas are the most abundant form of bone malignancies in multiple species. Canine osteosarcomas are considered a valuable model for human osteosarcomas because of their similar features. Feline osteosarcomas, on the other hand, are rarely studied but have interesting characteristics, such as a better survival prognosis than dogs or humans, and less likelihood of metastasis. To enable experimental approaches to study these differences we have established five new canine osteosarcoma cell lines out of three tumors, COS_1186h, COS_1186w, COS_1189, and COS_1220, one osteosarcoma-derived lung metastasis, COS_1033, and two new feline osteosarcoma cell lines, FOS_1077 and FOS_1140. Their osteogenic and neoplastic origin, as well as their potential to produce calcified structures, was determined by the markers osteocalcin, osteonectin, tissue unspecific alkaline phosphatase, p53, cytokeratin, vimentin, and alizarin red. The newly developed cell lines retained most of their markers in vitro but only spontaneously formed spheroids produced by COS_1189 showed calcification in vitro.

Trends in popularity of some morphological traits of purebred dogs in Australia

BACKGROUND

The morphology of dogs can provide information about their predisposition to some disorders. For example, larger breeds are predisposed to hip dysplasia and many neoplastic diseases. Therefore, longitudinal trends in popularity of dog morphology can reveal potential disease pervasiveness in the future. There have been reports on the popularity of particular breeds and behavioural traits but trends in the morphological traits of preferred breeds have not been studied.

METHODS

This study investigated trends in the height, dog size and head shape (cephalic index) of Australian purebred dogs. One hundred eighty-one breeds derived from Australian National Kennel Council (ANKC) registration statistics from 1986 to 2013 were analysed. Weighted regression analyses were conducted to examine trends in the traits by using them as outcome variables, with year as the explanatory variable and numbers of registered dogs as weights. Linear regression investigated dog height and cephalic index (skull width/skull length), and multinomial logistic regression studied dog size.

RESULTS

The total number of ANKC registration had decreased gradually from 95,792 in 1986 to 66,902 in 2013. Both weighted minimal height (p = 0.014) and weighted maximal height (p < 0.001) decreased significantly over time, and the weighted cephalic index increased significantly (p < 0.001). The odds of registration of medium and small breeds increased by 5.3 % and 4.2 %, respectively, relative to large breeds (p < 0.001) and by 12.1 % and 11.0 %, respectively, relative to giant breeds (p < 0.001) for each 5-year block of time.

CONCLUSIONS

Compared to taller and larger breeds, shorter and smaller breeds have become relatively popular over time. Mean cephalic index has increased, which indicates that Australians have gradually favoured breeds with shorter and wider heads (brachycephalic). These significant trends indicate that the dog morphological traits reported here may potentially influence how people select companion dogs in Australia and provide valuable predictive information on the pervasiveness of diseases in dogs.

Dogs as a Model for Cancer

Spontaneous cancers in client-owned dogs closely recapitulate their human counterparts with respect to clinical presentation, histological features, molecular profiles, and response and resistance to therapy, as well as the evolution of drug-resistant metastases. In several instances the incorporation of dogs with cancer into the preclinical development path of cancer therapeutics has influenced outcome by helping to establish pharmacokinetic/pharmacodynamics relationships, dose/regimen, expected clinical toxicities, and ultimately the potential for biologic activity. As our understanding regarding the molecular drivers of canine cancers has improved, unique opportunities have emerged to leverage this spontaneous model to better guide cancer drug development so that therapies likely to fail are eliminated earlier and therapies with true potential are optimized prior to human studies. Both pets and people benefit from this approach, as it provides dogs with access to cutting-edge cancer treatments and helps to insure that people are given treatments more likely to succeed.

Antigen profiling analysis of vaccinia virus injected canine tumors: oncolytic virus efficiency predicted by boolean models

Virotherapy on the basis of oncolytic vaccinia virus (VACV) strains is a novel approach for cancer therapy. In this study we describe for the first time the use of dynamic boolean modeling for tumor growth prediction of vaccinia virus GLV-1h68-injected canine tumors including canine mammary adenoma (ZMTH3), canine mammary carcinoma (MTH52c), canine prostate carcinoma (CT1258), and canine soft tissue sarcoma (STSA-1). Additionally, the STSA-1 xenografted mice were injected with either LIVP 1.1.1 or LIVP 5.1.1 vaccinia virus strains.   Antigen profiling data of the four different vaccinia virus-injected canine tumors were obtained, analyzed and used to calculate differences in the tumor growth signaling network by type and tumor type. Our model combines networks for apoptosis, MAPK, p53, WNT, Hedgehog, TK cell, Interferon, and Interleukin signaling networks. The in silico findings conform with in vivo findings of tumor growth. Boolean modeling describes tumor growth and remission semi-quantitatively with a good fit to the data obtained for all cancer type variants. At the same time it monitors all signaling activities as a basis for treatment planning according to antigen levels. Mitigation and elimination of VACV- susceptible tumor types as well as effects on the non-susceptible type CT1258 are predicted correctly. Thus the combination of Antigen profiling and semi-quantitative modeling optimizes the therapy already before its start.

Preclinical Testing Oncolytic Vaccinia Virus Strain GLV-5b451 Expressing an Anti-VEGF Single-Chain Antibody for Canine Cancer Therapy

Virotherapy on the basis of oncolytic vaccinia virus (VACV) strains is a novel approach for canine cancer therapy. Here we describe, for the first time, the characterization and the use of VACV strain GLV-5b451 expressing the anti-vascular endothelial growth factor (VEGF) single-chain antibody (scAb) GLAF-2 as therapeutic agent against different canine cancers. Cell culture data demonstrated that GLV-5b451 efficiently infected and destroyed all four tested canine cancer cell lines including: mammary carcinoma (MTH52c), mammary adenoma (ZMTH3), prostate carcinoma (CT1258), and soft tissue sarcoma (STSA-1). The GLV-5b451 virus-mediated production of GLAF-2 antibody was observed in all four cancer cell lines. In addition, this antibody specifically recognized canine VEGF. Finally, in canine soft tissue sarcoma (CSTS) xenografted mice, a single systemic administration of GLV-5b451 was found to be safe and led to anti-tumor effects resulting in the significant reduction and substantial long-term inhibition of tumor growth. A CD31-based immuno-staining showed significantly decreased neo-angiogenesis in GLV-5b451-treated tumors compared to the controls. In summary, these findings indicate that GLV-5b451 has potential for use as a therapeutic agent in the treatment of CSTS.

Current concepts in oncologic surgery in small animals

Surgical oncology is experiencing rapid transition in veterinary medicine. Mast cell tumors and soft tissue sarcomas are two of the most common neoplasms in small animal patients. Clinicians should be familiar with the need for staging and the procedures involved in treating patients with these tumors. Clinicians should be comfortable with available adjuvant therapies and when to use them in certain patients.

The oncolytic effects of reovirus in canine solid tumor cell lines

Oncolytic virotherapy is a new strategy for cancer treatment for humans and dogs. Reovirus has been proven to be a potent oncolytic virus in human medicine. Our laboratory has previously reported that canine mast cell tumor and canine lymphoma were susceptible to reovirus. In this study, canine solid tumor cell lines (mammary gland tumor, osteosarcoma and malignant melanoma) were tested to determine their susceptibility towards reovirus. We demonstrated that reovirus induces more than 50% cell death in three canine mammary gland tumors and one canine malignant melanoma cell line. The reovirus-induced cell death occurred via the activation of caspase 3. Ras activation has been shown to be one of the important mechanisms of reovirus-susceptibility in human cancers. However, Ras activation was not related to the reovirus-susceptibility in canine solid tumor cell lines, which was similar to reports in canine mast cell tumor and canine lymphoma. The results of this study highly suggest that canine mammary gland tumor and canine malignant melanoma are also potential candidates for reovirus therapy in veterinary oncology.

Persistent viremia by a novel parvovirus in a slow loris (Nycticebus coucang) with diffuse histiocytic sarcoma

Cancer is one of the leading health concerns for human and animal health. Since the tumorigenesis process is not completely understood and it is known that some viruses can induce carcinogenesis, it is highly important to identify novel oncoviruses and extensively study underlying oncogenic mechanisms. Here, we investigated a case of diffuse histiocytic sarcoma in a 22 year old slow loris (Nycticebus coucang), using a broad spectrum virus discovery technique. A novel parvovirus was discovered and the phylogenetic analysis performed on its fully sequenced genome demonstrated that it represents the first member of a novel genus. The possible causative correlation between this virus and the malignancy was further investigated and 20 serum and 61 organ samples from 25 animals (N. coucang and N. pygmaeus) were screened for the novel virus but only samples collected from the originally infected animal were positive. The virus was present in all tested organs (intestine, liver, spleen, kidneys, and lungs) and in all banked serum samples collected up to 8 years before death. All attempts to identify a latent viral form (integrated or episomal) were unsuccessful and the increase of variation in the viral sequences during the years was consistent with absence of latency. Since it is well known that parvoviruses are dependent on cell division to successfully replicate, we hypothesized that the virus could have benefitted from the constantly dividing cancer cells and may not have been the cause of the histiocytic sarcoma. It is also possible to conjecture that the virus had a role in delaying the tumor progression and this report might bring new exciting opportunities in recognizing viruses to be used in cancer virotherapy.

Evaluation of a modified proportional margins approach for surgical resection of mast cell tumors in dogs: 40 cases (2008-2012)

OBJECTIVE

To evaluate a modified proportional margins approach to resection of mast cell tumors (MCTs) in dogs.

DESIGN

Retrospective case series.

ANIMALS

40 dogs with subcutaneous and cutaneous MCTs undergoing curative intent surgery.

PROCEDURES

Medical records were searched to identify dogs with a cytologically or histologically confirmed diagnosis of MCT that had not previously been treated surgically and that had undergone full oncological staging. In those dogs, tumors were resected with lateral margins equivalent to the widest measured diameter of the tumor and a minimum depth of 1 well-defined fascial plane deep to the tumor. Surgical margins were evaluated histologically. Cutaneous tumors were graded by use of the Patnaik system and the 2-tier system described by Kiupel et al. The prognosis for subcutaneous tumors was assessed in accordance with published recommendations. Follow-up information on dog health status was obtained through clinical examination, the dog owners, and the referring veterinarians.

RESULTS

The 40 dogs had 47 tumors. Forty-one (87%) tumors were cutaneous, and 6 (13%) were subcutaneous. On the basis of the Patnaik system, 21 (51%) cutaneous tumors were considered grade I, 18 (44%) were considered grade II, and 2 (5%) were considered grade III. On the basis of the Kiupel system, 37 (90%) cutaneous tumors were considered low grade, and 4 (10%) were considered high grade. The prognosis for the 6 subcutaneous tumors was classified as likely resulting in a shorter (2) or longer (4) survival time. Forty tumors were deemed to have been excised with clear margins and 7 with incomplete margins. Local recurrence was not recorded for any dog but was suspected for 1 (2%) tumor, although not confirmed. Interval from tumor excision to follow-up ranged from 30 to 1,140 days (median, 420 days).

CONCLUSIONS AND CLINICAL RELEVANCE

The modified proportional margins system resulted in satisfactory local disease control in dogs with MCTs.

Oncolytic virotherapy of canine and feline cancer

Cancer is the leading cause of disease-related death in companion animals such as dogs and cats. Despite recent progress in the diagnosis and treatment of advanced canine and feline cancer, overall patient treatment outcome has not been substantially improved. Virotherapy using oncolytic viruses is one promising new strategy for cancer therapy. Oncolytic viruses (OVs) preferentially infect and lyse cancer cells, without causing excessive damage to surrounding healthy tissue, and initiate tumor-specific immunity. The current review describes the use of different oncolytic viruses for cancer therapy and their application to canine and feline cancer.

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.

Detection of herbicides in the urine of pet dogs following home lawn chemical application

Exposure to herbicide-treated lawns has been associated with significantly higher bladder cancer risk in dogs. This work was performed to further characterize lawn chemical exposures in dogs, and to determine environmental factors associated with chemical residence time on grass. In addition to concern for canine health, a strong justification for the work was that dogs may serve as sentinels for potentially harmful environmental exposures in humans. Experimentally, herbicides [2,4-dichlorophenoxyacetic acid (2,4-D), 4-chloro-2-methylphenoxypropionic acid (MCPP), dicamba] were applied to grass plots under different conditions (e.g., green, dry brown, wet, and recently mowed grass). Chemicals in dislodgeable residues were measured by LC-MS at 0.17, 1, 24, 48, 72 h post treatment. In a separate study, 2,4-D, MCPP, and dithiopyr concentrations were measured in the urine of dogs and in dislodgeable grass residues in households that applied or did not apply chemicals in the preceding 48 h. Chemicals were measured at 0, 24, and 48 h post application in treated households and at time 0 in untreated control households. Residence times of 2,4-D, MCPP, and dicamba were significantly prolonged (P<0.05) on dry brown grass compared to green grass. Chemicals were detected in the urine of dogs in 14 of 25 households before lawn treatment, in 19 of 25 households after lawn treatment, and in 4 of 8 untreated households. Chemicals were commonly detected in grass residues from treated lawns, and from untreated lawns suggesting chemical drift from nearby treated areas. Thus dogs could be exposed to chemicals through contact with their own lawn (treated or contaminated through drift) or through contact with other grassy areas if they travel. The length of time to restrict a dog's access to treated lawns following treatment remains to be defined. Further study is indicated to assess the risks of herbicide exposure in humans and dogs.

Characterization and evaluation of a new oncolytic vaccinia virus strain LIVP6.1.1 for canine cancer therapy

Virotherapy on the basis of oncolytic vaccinia virus (VACV) strains is one novel approach for canine cancer therapy. In this study we described for the first time the characterization and the use of new VACV strain LIVP6.1.1 as an oncolytic agent against canine cancer in a panel of four canine cancer cell lines including: soft tissue sarcoma (STSA-1), melanoma (CHAS), osteosarcoma (D-17) and prostate carcinoma (DT08/40). Cell culture data demonstrated that LIVP6.1.1 efficiently infected and destroyed all four tested canine cancer cell lines. In two different xenograft models on the basis of the canine soft tissue sarcoma STSA-1 and the prostate carcinoma DT08/40 cell lines, a systemic administration of the LIVP6.1.1 virus was found to be safe and led to anti-tumor and immunological effects resulting in the significant reduction of tumor growth in comparison to untreated control mice. In summary, the pre-clinical evaluation has demonstrated the efficacy of LIVP6.1.1 for canine cancer therapy. Furthermore, a clinical trial with canine cancer patients has already been started.

Virotherapy of canine tumors with oncolytic vaccinia virus GLV-1h109 expressing an anti-VEGF single-chain antibody

Virotherapy using oncolytic vaccinia virus (VACV) strains is one promising new strategy for cancer therapy. We have previously reported that oncolytic vaccinia virus strains expressing an anti-VEGF (Vascular Endothelial Growth Factor) single-chain antibody (scAb) GLAF-1 exhibited significant therapeutic efficacy for treatment of human tumor xenografts. Here, we describe the use of oncolytic vaccinia virus GLV-1h109 encoding GLAF-1 for canine cancer therapy. In this study we analyzed the virus-mediated delivery and production of scAb GLAF-1 and the oncolytic and immunological effects of the GLV-1h109 vaccinia virus strain against canine soft tissue sarcoma and canine prostate carcinoma in xenograft models. Cell culture data demonstrated that the GLV-1h109 virus efficiently infect, replicate in and destroy both tested canine cancer cell lines. In addition, successful expression of GLAF-1 was demonstrated in virus-infected canine cancer cells and the antibody specifically recognized canine VEGF. In two different xenograft models, the systemic administration of the GLV-1h109 virus was found to be safe and led to anti-tumor and immunological effects resulting in the significant reduction of tumor growth in comparison to untreated control mice. Furthermore, tumor-specific virus infection led to a continued production of functional scAb GLAF-1, resulting in inhibition of angiogenesis. Overall, the GLV-1h109-mediated cancer therapy and production of immunotherapeutic anti-VEGF scAb may open the way for combination therapy concept i.e. vaccinia virus mediated oncolysis and intratumoral production of therapeutic drugs in canine cancer patients.

Biomonitoring the cooked meat carcinogen 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine in canine fur

2-Amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) is a heterocyclic aromatic amine (HAA) that is formed during the cooking of meat, poultry, and fish. PhIP is a rodent carcinogen and is thought to contribute to several diet-related cancers in humans. PhIP is present in the hair of human omnivores but not in the hair of vegetarians. We have now identified PhIP in the fur of 14 out of 16 healthy dogs consuming different brands of commercial pet food. The levels of PhIP in canine fur varied by over 85-fold and were comparable to the levels of PhIP present in human hair. However, high density fur containing PhIP covers a very high proportion of the body surface area of dogs, whereas high density terminal hair primarily covers the scalp and pubis body surface area of humans. These findings signify that the exposure and bioavailability of PhIP are high in canines. A potential role for PhIP in the etiology of canine cancer should be considered.

Identification of the most common cutaneous neoplasms in dogs and evaluation of breed and age distributions for selected neoplasms

OBJECTIVE-To identify the most common cutaneous neoplasms in dogs and evaluate breed and age distributions for selected neoplasms. DESIGN-Retrospective epidemiological study. SAMPLE-Records available through the Veterinary Medical Database of dogs examined at veterinary teaching hospitals in North America between 1964 and 2002. PROCEDURES-Information on tumor type and patient breed and age was collected. Incidence and odds ratios with 95% confidence intervals were calculated. RESULTS-Records of 1,139,616 dogs were reviewed. Cutaneous neoplasms were diagnosed in 25,996 of these dogs; records for the remaining 1,113,620 dogs did not indicate that cutaneous neoplasms had been diagnosed, and these dogs were considered controls. The most frequent age range for dogs with cutaneous neoplasms was 10 to 15 years. Lipoma, adenoma, and mast cell tumor were the most common skin tumor types. CONCLUSIONS AND CLINICAL RELEVANCE-Results supported previously reported data regarding cutaneous neoplasia in dogs but provided updated information on the most common skin tumors and on age and breed distributions.

CD40 ligand is necessary and sufficient to support primary diffuse large B-cell lymphoma cells in culture: a tool for in vitro preclinical studies with primary B-cell malignancies

Established cell lines are utilized extensively to study tumor biology and preclinical therapeutic development. However, they may not accurately recapitulate the heterogeneity of their corresponding primary disease. B-cell tumor cells are especially difficult to maintain under conventional culture conditions, limiting access to samples that faithfully represent this disease for preclinical studies. Here, we used primary canine diffuse large B-cell lymphoma to establish a culture system that reliably supports the growth of these cells. CD40 ligand, either expressed by feeder cells or provided as a soluble two-trimeric form, was sufficient to support primary lymphoma cells in vitro. The tumor cells retained their original phenotype, clonality and known karyotypic abnormalities after extended expansion in culture. Finally, we illustrate the utility of the feeder cell-free culture system for comparable assessment of cytotoxicity using dog and human B-cell malignancies. We conclude that this system has broad applications for in vitro preclinical development for B-cell malignancies.

Oncolytic virotherapy in veterinary medicine: current status and future prospects for canine patients

Oncolytic viruses refer to those that are able to eliminate malignancies by direct targeting and lysis of cancer cells, leaving non-cancerous tissues unharmed. Several oncolytic viruses including adenovirus strains, canine distemper virus and vaccinia virus strains have been used for canine cancer therapy in preclinical studies. However, in contrast to human studies, clinical trials with oncolytic viruses for canine cancer patients have not been reported. An 'ideal' virus has yet to be identified. This review is focused on the prospective use of oncolytic viruses in the treatment of canine tumors - a knowledge that will undoubtedly contribute to the development of oncolytic viral agents for canine cancer therapy in the future.

Household chemical exposures and the risk of canine malignant lymphoma, a model for human non-Hodgkin's lymphoma

BACKGROUND

Epidemiologic studies of companion animals offer an important opportunity to identify risk factors for cancers in animals and humans. Canine malignant lymphoma (CML) has been established as a model for non-Hodgkin's lymphoma (NHL). Previous studies have suggested that exposure to environmental chemicals may relate to development of CML.

METHODS

We assessed the relation of exposure to flea and tick control products and lawn-care products and risk of CML in a case-control study of dogs presented to a tertiary-care veterinary hospital (2000-2006). Cases were 263 dogs with biopsy-confirmed CML. Controls included 240 dogs with benign tumors and 230 dogs undergoing surgeries unrelated to cancer. Dog owners completed a 10-page questionnaire measuring demographic, environmental, and medical factors.

RESULTS

After adjustment for age, weight, and other factors, use of specific lawn care products was associated with greater risk of CML. Specifically, the use of professionally applied pesticides was associated with a significant 70% higher risk of CML (odds ratio(OR)=1.7; 95% confidence interval (CI)=1.1-2.7). Risk was also higher in those reporting use of self-applied insect growth regulators (OR=2.7; 95% CI=1.1-6.8). The use of flea and tick control products was unrelated to risk of CML.

CONCLUSIONS

Results suggest that use of some lawn care chemicals may increase the risk of CML. Additional analyses are needed to evaluate whether specific chemicals in these products may be related to risk of CML, and perhaps to human NHL as well.

Animal sentinels for environmental and public health

Studies of the effects of environmental exposures on domestic and wild animals can corroborate or inform epidemiologic studies in humans. Animals may be sensitive indicators of environmental hazards and provide an early warning system for public health intervention, as exemplified by the iconic canary in the coal mine. This article illustrates the application of animal sentinel research to elucidate the effects of exposure to traditional and emerging contaminants on human health. Focusing on environmental issues at the forefront of current public health research, the article describes exposures to community air pollution, environmental tobacco smoke, and pesticides and associations with cancer, reproductive outcomes, and infectious diseases. Finally, it covers the role of marine mammals in monitoring the health of the oceans and humans.

Environmental tobacco smoke and canine urinary cotinine level

Epidemiologic studies of companion animals such as dogs have been established as models for the relationship between exposure to environmental tobacco smoke (ETS) and cancer risk in humans. While results from these studies are provocative, pet owner report of a dog's ETS exposure has not yet been validated. We have evaluated the relationship between dog owner's report of household smoking by questionnaire and dog's urinary cotinine level. Between January and October 2005, dog owners presenting their pet for non-emergency veterinary care at the Foster Hospital for Small Animals at Cummings School of Veterinary Medicine, Tufts University, were asked to complete a 10-page questionnaire measuring exposure to household ETS in the previous 24 h and other factors. A free-catch urine sample was also collected from dogs. Urinary cotinine level was assayed for 63 dogs, including 30 whose owners reported household smoking and 33 unexposed dogs matched on age and month of enrollment. Urinary cotinine level was significantly higher in dogs exposed to household smoking in the 24 h before urine collection compared to unexposed dogs (14.6 ng/ml vs. 7.4 ng/ml; P=0.02). After adjustment for other factors, cotinine level increased linearly with number of cigarettes smoked by all household members (P=0.004). Other canine characteristics including age, body composition and nose length were also associated with cotinine level. Findings from our study suggest that household smoking levels as assessed by questionnaire are significantly associated with canine cotinine levels.

Roles of estrogen receptor alpha and beta in modulating urothelial cell proliferation

We reported previously that both subtypes of estrogen receptors, ERalpha and ERbeta, are expressed by human urothelial cells and mediate estrogen-induced cell proliferation in these cells. The aim of this study was to determine the extent to which each ER subtype contributes to urothelial cell proliferation and their possible involvement in the regulation of the cell cycle. We compared the expression of ERalpha and ERbeta mRNAs and protein quantitatively in primarily cultured human bladder urothelial cells obtained from six individuals with three immortalized urothelial (E6, E7, and UROtsa) and two bladder cancer cell lines (HTB-9 and T24). We found that all these cells express similar levels of ERbeta, but immortalized and cancer cells express much higher amounts of ERalpha than primary cells. Higher levels of ERalpha mRNA were also observed in the biopsies of bladder transitional cell carcinoma compared with sample from the same bladder unaffected by tumor. Using the ERalpha-selective agonist PPT, the ERbeta-selective agonist DPN, and specific small interfering RNA against ERalpha or ERbeta, we found that ERbeta predominantly mediates estrogen-induced G1/S transition and cell proliferation in the primary urothelial cells. By contrast, ERalpha predominantly mediates estrogen-induced G1/S transition and cell proliferation in bladder cancer cell lines. Furthermore, we found that 17beta-estradiol (E(2)) rapidly induces phosphorylation of extracellular signal-regulated kinases, but U0126, a mitogen-activated protein kinase kinase (MEK) inhibitor, does not affect E(2)-induced urothelial cell proliferation. E(2) up-regulated cyclin D1 and cyclin E expression in both the primary and bladder cancer cells, and the cancer cells have higher cyclin D1 and cyclin E expression during G0/G1 phases. Our data suggest that estrogen exerts its effects through different ER subtypes in urothelial cells. Increased expression of ERalpha may contribute to early induction of cyclin D1 and cyclin E during the cell cycle in bladder cancer cells.

Spontaneous and genetically engineered animal models; use in preclinical cancer drug development

The preclinical development of anticancer drugs has been based primarily on the transplantation of murine or human cancers into mice. Alternatives to these transplantation models are animals that naturally develop cancers with features relevant to the human disease. The first group of these models arises in mice that are genetically engineered to develop cancer. The second group includes pet dogs and cats that naturally develop cancer. This review will discuss the use and integration of these spontaneous cancer models into a comprehensive and comparative approach to preclinical drug development. Examples of their successful use and an outline of their relative strengths and weaknesses will be provided.

Mutagenic activity and heterocyclic amine carcinogens in commercial pet foods

Twenty-five commercial pet foods were analyzed for mutagenic activity using the Ames/Salmonella test with strain TA98 and added metabolic activation. All but one gave a positive mutagenic response. Fourteen of these samples were analyzed for heterocyclic amine mutagens/carcinogens and all but one contained 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx) and 10 of 14 contained 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) as analyzed by HPLC and confirmed by photodiode array peak matching. From these findings it is hypothesized that there is a connection between dietary heterocyclic amines and cancer in animals consuming these foods.

An epidemiological analysis of a canine-biopsies database compiled by a diagnostic histopathology service

A case-control study was carried out on data from 21,371 canine tissue biopsies submitted to the external histopathology diagnostic service at the University of Glasgow Veterinary School (GUVS) over a 12.5-year period. Biopsies were received from 545 privately owned and charity veterinary practices located throughout the UK. The overall prevalence of neoplasia in samples with a confirmed diagnosis was 58.7%. A total of 156 pure breeds were represented in the dataset, with 22.2% of samples originating from mixed-breed dogs. Univariable and multivariable analyses assessed the effects of sex, breed, age and site on the likelihood of a diagnosis of neoplasia. Logistic regression showed that the highest odds ratio was associated with the mammary gland (OR=6.53;skin=the referent category). Using the Labrador retriever as the referent breed, Boxers had increased odds of neoplasia; the German shepherd dog and Doberman were among breeds with decreased odds ratios. Intact females and dogs over the age of 10 years were (unsurprisingly) also high-risk groups. Potential sources of bias influencing the dataset include the relative ease with which clinical abnormalities of the skin and mammary gland initially are detected by sight and/or palpation, compared with other organs. The high prevalence of biopsies originating from the skin and mammary gland is also likely to reflect the readiness of the veterinarian to biopsy lesions in these sites, compared with sites within the body cavities. The findings confirm many of the perceived risks for neoplasia based on previous clinical descriptive and univariable investigations. The results might also assist the pathologist in prioritisation of biopsy examination in busy histopathology laboratories.