Inheritance of histiocytosis in Bernese mountain dogs

Identification of common predisposing loci to hematopoietic cancers in four dog breeds

Histiocytic sarcoma (HS) is a rare but aggressive cancer in both humans and dogs. The spontaneous canine model, which has clinical, epidemiological, and histological similarities with human HS and specific breed predispositions, provides a unique opportunity to unravel the genetic basis of this cancer. In this study, we aimed to identify germline risk factors associated with the development of HS in canine-predisposed breeds. We used a methodology that combined several genome-wide association studies in a multi-breed and multi-cancer approach as well as targeted next-generation sequencing, and imputation We combined several dog breeds (Bernese mountain dogs, Rottweilers, flat-coated retrievers, and golden retrievers), and three hematopoietic cancers (HS, lymphoma, and mast cell tumor). Results showed that we not only refined the previously identified HS risk CDKN2A locus, but also identified new loci on canine chromosomes 2, 5, 14, and 20. Capture and targeted sequencing of specific loci suggested the existence of regulatory variants in non-coding regions and methylation mechanisms linked to risk haplotypes, which lead to strong cancer predisposition in specific dog breeds. We also showed that these canine cancer predisposing loci appeared to be due to the additive effect of several risk haplotypes involved in other hematopoietic cancers such as lymphoma or mast cell tumors as well. This illustrates the pleiotropic nature of these canine cancer loci as observed in human oncology, thereby reinforcing the interest of predisposed dog breeds to study cancer initiation and progression.

Because of specific breed structures and artificial selection, pet dogs suffer from numerous genetic diseases, including cancers and represent a unique spontaneous model of human cancers. Here, we focused on histiocytic sarcoma (HS), a rare and highly aggressive cancer in humans. In this study, we have used spontaneous affected and unaffected dogs from three predisposed dog breeds to identify loci involved in HS predisposition. Through genetic analyses, we showed that these canine cancer predispositions are due to the additive effect of several risk haplotypes also involved in the predisposition of other hematopoietic cancers. The corresponding chromosomal regions in humans are involved in the predisposition of several cancers and are also associated with immune traits. This study demonstrates the pleiotropic nature of these canine cancer loci as observed in human oncology, thereby reinforcing the interest of predisposed dog breeds to study mechanisms involved in cancer initiation.

Histiocytic sarcoma in miniature schnauzers: 30 cases

OBJECTIVES

To summarise the clinical presentation and outcomes in a series of miniature schnauzers diagnosed with histiocytic sarcoma.

MATERIALS AND METHODS

Retrospective review of medical records of miniature schnauzers diagnosed with histiocytic sarcoma between 2008 and 2019 at two referral centres in the UK. Signalment, clinical signs at initial presentation, imaging results and clinico- and histopathological findings, treatment type and outcome were recorded. Progression-free survival and overall survival time were calculated.

RESULTS

Thirty dogs were included. Twenty-four of 29 dogs undergoing imaging of the thorax had lung and/or mediastinal involvement. The median overall survival time for dogs that were not euthanased within 3 days of diagnosis was 117 days (range 10 to 790). Three dogs underwent surgery; 13 received treatment with lomustine as a sole therapy - with partial responses documented on imaging in five of six dogs and 11 of 13 showing clinical improvement.

CLINICAL SIGNIFICANCE

Histiocytic sarcoma should be considered as a differential diagnosis for miniature schnauzers with pulmonary masses. Although responses to treatment were common, they were usually short-lived because of the aggressive nature of the disease.

Refining the "double two-thirds" rule: Genotype-based breed grouping and clinical presentation help predict the diagnosis of canine splenic mass lesions in 288 dogs

Prediction of the likely histopathological diagnosis of canine splenic masses can guide appropriate decision-making. This study explores the predictive effect of breed and clinical presentation on the diagnosis of a canine splenic mass. Records from the Royal Veterinary College, United Kingdom (2007-2017) were reviewed. Dogs with a histopathologic or cytologic diagnosis from a splenic mass, or imaging findings consistent with disseminated metastatic disease, were included. Signalment, physical examination, haematology results, imaging findings and pathology reports were recorded. Breeds were grouped according to several permutations of their phenotype and then by clustering of breeds based on single nucleotide polymorphism analysis. Binary logistic regression was performed to identify predictors of malignancy and haemangiosarcoma. Two hundred and eighty-eight dogs were identified: 27% female and 63% male, 21% entire and 79% neutered; German Shepherd was the most common breed (11%). Median age was 10 years and median bodyweight 25 kg. Thirty-eight percent of dogs presented with haemoabdomen; a splenic mass was found incidentally in 28%. Sixty percent had a malignant tumour of which haemangiosarcoma comprised 66%. On multivariable analysis, genotype-based breed group (P = .004), haemoabdomen (P < .001) and neutrophil count (P = .025) predicted malignancy, and genotype-based breed group (P < .001) and haemoabdomen (P < .001) predicted haemangiosarcoma. Genotype-based breed group and occurrence of haemoabdomen may have predictive value to diagnose malignant splenic masses and more specifically haemangiosarcoma. The effect of genotype-based breed grouping was a superior predictor of the diagnosis of a canine splenic mass lesion compared with all phenotype-based groupings tested.

Suggested Case of Langerhans Cell Histiocytosis in a Cretaceous dinosaur

Susceptibility to diseases is common to humans and dinosaurs. Since much of the biological history of every living creature is shaped by its diseases, recognizing them in fossilized bone can furnish us with important information on dinosaurs' physiology and anatomy, as well as on their daily activities and surrounding environment. In the present study, we examined the vertebrae of two humans from skeletal collections with Langerhans Cell Histiocytosis (LCH), a benign osteolytic tumor-like disorder involving mainly the skeleton; they were diagnosed in life, along with two hadrosaur vertebrae with an apparent lesion. Macroscopic and microscopic analyses of the hadrosaur vertebrae were compared to human LCH and to other pathologies observed via an extensive pathological survey of a human skeletal collection, as well as a three-dimensional reconstruction of the lesion and its associated blood vessels from a µCT scan. The hadrosaur pathology findings were indistinguishable from those of humans with LCH, supporting that diagnosis. This report suggests that hadrosaurids had suffered from larger variety of pathologies than previously reported. Furthermore, it seems that LCH may be independent of phylogeny.

Clinicopathological characteristics of histiocytic sarcoma affecting the central nervous system in dogs

BACKGROUND

Histiocytic sarcoma affecting the central nervous system (CNS HS) in dogs may present as primary or disseminated disease, often characterized by inflammation. Prognosis is poor, and imaging differentiation from other CNS tumors can be problematic.

OBJECTIVE

To characterize the clinicopathological inflammatory features, breed predisposition, and survival in dogs with CNS HS.

ANIMALS

One hundred two dogs with HS, 62 dogs with meningioma.

METHODS

Retrospective case series. Records were reviewed for results of cerebrospinal fluid (CSF) analysis, CBC, treatment, and outcome data.

RESULTS

Predisposition for CNS HS was seen in Bernese Mountain Dogs, Golden Retrievers, Rottweilers, Corgis, and Shetland Sheepdogs (P ≤ .001). Corgis and Shetland Sheepdogs had predominantly primary tumors; Rottweilers had exclusively disseminated tumors. Marked CSF inflammation was characteristic of primary rather than disseminated HS, and neoplastic cells were detected in CSF of 52% of affected dogs. Increased neutrophil to lymphocyte ratios were seen in all groups relative to controls (P <.008) but not among tumor subtypes. Definitive versus palliative treatment resulted in improved survival times (P < .001), but overall prognosis was poor.

CONCLUSIONS AND CLINICAL IMPORTANCE

Clinicopathological differences between primary and disseminated HS suggest that tumor biological behavior and origin may be different. Corgis and Shetland Sheepdogs are predisposed to primary CNS HS, characterized by inflammatory CSF. High total nucleated cell count and the presence of neoplastic cells support the use of CSF analysis as a valuable diagnostic test. Prognosis for CNS HS is poor, but further evaluation of inflammatory mechanisms may provide novel therapeutic opportunities.

Effect of a two-base insertion mutation of the TP53 gene on expression of p53 protein in canine histiocytic sarcoma cells

OBJECTIVE

To examine effects of a common mutation (2-base insertion in exon 5) of the TP53 gene on biological function of p53 protein in canine histiocytic sarcoma cells.

SAMPLE

Canine histiocytic tumor cell lines DH82 with deletion of TP53 and CHS-3 with the wild-type TP53 and canine wild-type and mutant TP53 fragments.

PROCEDURES

Wild-type or mutant TP53 with a polyprotein peptide tag at the N-terminus was transduced into DH82 and CHS-3 cells. Expression of p53 protein, changes in function as a transcription factor, and susceptibility to doxorubicin and nimustine were compared.

RESULTS

Transduced p53 protein was detected in wild-type TP53-transduced DH82 and CHS-3 cells, whereas expression was not detected in mutant TP53-transduced cells. There were significant increases in expression of target genes of p53 protein, including p21 and MDM2, in wild-type TP53-transduced cells, compared with results for native and mock-transfected cells, but not in mutant TP53-transduced cells. There was no significant difference in drug susceptibilities among native and derivative cells of CHS-3. However, cell viabilities of wild-type TP53-transduced DH82 cells incubated with doxorubicin were significantly lower than viabilities of native, mock-transfected, and AT insertion mutation-TP53-transduced DH82 cells; susceptibility to nimustine did not differ significantly among cells.

CONCLUSIONS AND CLINICAL RELEVANCE

Expression of p53 protein and its function as a transcription factor were lost after addition of a 2-base insertion in the TP53 gene in canine histiocytic tumor cells. Additional studies are needed to investigate the clinical relevance of this mutation in histiocytic sarcomas of dogs.

Canine Cancer Genomics: Lessons for Canine and Human Health

Dogs are second only to humans in medical surveillance and preventative health care, leading to a recent perception of increased cancer incidence. Scientific priorities in veterinary oncology have thus shifted, with a demand for cancer genetic screens, better diagnostics, and more effective therapies. Most dog breeds came into existence within the last 300 years, and many are derived from small numbers of founders. Each has undergone strong artificial selection, in which dog fanciers selected for many traits, including body size, fur type, color, skull shape, and behavior, to create novel breeds. The adoption of the breed barrier rule-no dog may become a registered member of a breed unless both its dam and its sire are registered members-ensures a relatively closed genetic pool within each breed. As a result, there is strong phenotypic homogeneity within breeds but extraordinary phenotypic variation between breeds. One consequence of this is the high level of breed-associated genetic disease. We and others have taken advantage of this to identify genes for a large number of canine maladies for which mouse models do not exist, particularly with regard to cancer.

Canine sarcomas as a surrogate for the human disease

Pet dogs are becoming increasingly recognized as a population with the potential to inform medical research through their treatment for a variety of maladies by veterinary health professionals. This is the basis of the One Health initiative, supporting the idea of collaboration between human and animal health researchers and clinicians to study spontaneous disease processes and treatment in animals to inform human health. Cancer is a major health burden in pet dogs, accounting for approximately 30% of deaths across breeds. As such, pet dogs with cancer are becoming increasingly recognized as a resource for studying the pharmacology and therapeutic potential of anticancer drugs and therapies under development. This was recently highlighted by a National Academy of Medicine Workshop on Comparative Oncology that took place in mid-2015 (http://www.nap.edu/21830). One component of cancer burden in dogs is their significantly higher incidence of sarcomas as compared to humans. This increased incidence led to canine osteosarcoma being an important component in the development of surgical approaches for osteosarcoma in children. Included in this review of sarcomas in dogs is a description of the incidence, pathology, molecular characteristics and previous translational therapeutic studies associated with these tumors. An understanding of the patho-physiological and molecular characteristics of these naturally occurring canine sarcomas holds great promise for effective incorporation into drug development schemas, for evaluation of target modulation or other pharmacodynamic measures associated with therapeutic response. These data could serve to supplement other preclinical data and bolster clinical investigations in tumor types for which there is a paucity of human patients for clinical trials.

A 2-base insertion in exon 5 is a common mutation of the TP53 gene in dogs with histiocytic sarcoma

Canine histiocytic sarcoma (HS) is a malignancy originating from the histiocytic cell lineage and characterized by poor response to chemotherapy and short survival time. Mutation of the TP53 gene and its association with poor prognosis has been reported in several canine tumors. However, the mutation of this gene has not been investigated in canine HS. The aim of this study was to examine a TP53 gene mutation in dogs with HS. Aberrations of the TP53 gene were examined by polymerase chain reaction-single strand conformational polymorphism analysis and DNA sequence analysis, revealing mutations of the TP53 gene in 12 (46%) of 26 dogs affected by HS. The incidence of the TP53 gene mutation was relatively high in canine HS compared with other canine tumors. Among these mutations, 10 of 12 dogs (83%) with a TP53 gene mutation harbored the same mutation: a 2-base (AT) insertion in exon 5, resulting in the introduction of a stop codon (c.446_447insAT, p.Tyr150SerfsX8). Further studies are needed to examine the functional change due to the mutation and its association with the pathogenesis of canine HS.

Prior joint disease is associated with increased risk of periarticular histiocytic sarcoma in dogs

Periarticular histiocytic sarcoma (PAHS) is the most common synovial tumour in dogs and is characterized by aggressive local disease with a high rate of distant metastasis. Previously, an association between PAHS and prior joint disease has been demonstrated in the Bernese Mountain Dog breed and suggested in the Rottweiler. We hypothesized that this association would be present in other breeds and investigated this via a retrospective, case-controlled analysis. Cases were dogs diagnosed with PAHS of the stifle or elbow. Controls were age, breed and sex-matched dogs without a diagnosis of histiocytic sarcoma. Diagnosis of prior joint disease was determined based on review of medical records and direct veterinarian and owner communications. Data were evaluated using logistic regression, 2-sampled t tests, and chi-squared analysis. Our study population consisted of 28 cases and 46 controls, including Flat-Coated, Golden and Labrador Retrievers, Rottweilers, English Bulldogs, Shih Tzus, Australian Shepherds, Staffordshire Terriers and mixed breed dogs. Dogs with PAHS were more likely to have prior joint disease in the tumour-affected joint compared with the control population (odds ratio [OR] = 13.42, P < .0001, 95% confidence interval [CI] = 4.33-48.63). A total of 88.2% of dogs with stifle PAHS had prior joint disease in their tumour-affected joint, most commonly cranial cruciate ligament rupture. This study confirms that the previously noted association between prior joint disease and PAHS in Bernese Mountain Dogs also applies to other breeds. Additional studies are needed to further investigate for a causal relationship.

Histiocytic sarcoma in 14 miniature schnauzers - a new breed predisposition?

OBJECTIVES

To describe a series of miniature schnauzers diagnosed with histiocytic sarcoma and assess for possible breed predisposition.

MATERIALS AND METHODS

Medical records of miniature schnauzers with a diagnosis of histiocytic sarcoma between January 2008 and April 2015 were reviewed. Data collected included signalment, body weight, presenting complaint, date of diagnosis, clinicopathologic and diagnostic imaging findings, treatment, therapeutic response, date of death or last follow-up and necropsy findings. Breed predisposition was assessed with odds ratios, using breed-matched dogs without histiocytic sarcoma admitted during the study period as controls. Pedigree analysis was performed for dogs with available registration information.

RESULTS

Fourteen miniature schnauzers were diagnosed with histiocytic sarcoma during the study period, making them over-represented among the hospital population (odds ratio=4·8, P=0·0009). Disease was considered localised in ten dogs and disseminated in four. Of the dogs with localised disease, nine were diagnosed with primary pulmonary histiocytic sarcoma based on the presence of a large pulmonary mass with (n=7) or without (n=2) evidence of intra-thoracic metastasis, and one had gastric histiocytic sarcoma with nodal metastasis. Treatments varied, but an aggressive clinical course was found in most patients. Pedigree analysis revealed a recent common ancestor for a subset of the dogs assessed.

CLINICAL SIGNIFICANCE

Miniature schnauzers were over-represented among dogs with histiocytic sarcoma in this patient population. Pedigree analysis supports an inherited risk factor, which has not previously been suggested in the breed. Primary pulmonary involvement with or without intra-thoracic metastasis was common in this cohort.

Life expectancy and causes of death in Bernese mountain dogs in Switzerland

BACKGROUND

New regulations by the Swiss Federal Food Safety and Veterinary Office provide for the monitoring of breed health by Swiss breeding clubs. In collaboration with the Swiss Bernese Mountain Dog Club, the purpose of this study was to investigate the causes of death in purebred dogs registered by the club and born in 2001 and 2002.

RESULTS

Of a total of 1290 Bernese mountain dogs (BMDs) born in 2001 and 2002 in Switzerland, data was collected from owners and veterinarians using a questionnaire designed for this study from 389 dogs (30.2 %). By the end of the study, 381/389 dogs (97.9 %) had died. The median life expectancy of all dogs was 8.4 years (IQR, 6.9-9.7). Female dogs had a significantly longer median survival (8.8 years; IQR, 7.1-10.3) than male dogs (7.7 years; IQR, 6.6-9.3) (P < 0.00). The cause of death was unknown in 89/381 dogs (23.4 %). For the remaining dogs, the most frequent causes of death were neoplasia (222/381, 58.3 %), degenerative joint disease (16/381, 4.2 %), spinal disorders (13/381, 3.4 %), renal injury (12/381, 3.1 %), and gastric or mesenteric volvulus (7/381, 1.8 %). However, large numbers of dogs were diagnosed with neoplasia without histopathologic or cytologic confirmation. Dogs with neoplasms had a shorter median survival than dogs with other disorders. The shortest median survival (6.8 years) was found for dogs with renal injury.

CONCLUSIONS

Findings of this study confirm a high prevalence of neoplasia and associated low life expectancy in BMDs. The results underline a need for more widespread precise diagnostics and further research on malignant tumours in this breed to improve overall breed health.

Risk Factors Associated with Development of Histiocytic Sarcoma in Bernese Mountain Dogs

BACKGROUND

Histiocytic sarcoma (HS) is a rare but aggressive malignancy in humans that is poorly responsive to existing treatments. Although rare in most breeds of dogs, HS is common in Bernese mountain dogs (BMDs).

OBJECTIVE

Determine risk factors associated with development of HS in BMD.

ANIMALS

A total of 216 BMD were registered with the Berner-Garde Foundation.

METHODS

An internet-based cross-sectional survey was used to collect information from owners of BMD diagnosed with HS and owners of disease-free littermates of dogs with HS. Mixed-effects logistic regression (MELR) and conditional logistic regression (CLR) were used in parallel to examine associations between potential risk factors and the occurrence of HS.

RESULTS

When controlling for litter as a marker of relatedness, dogs diagnosed with orthopedic conditions were found to be more likely to develop HS (MELR, OR: 2.5, 95% CI: 1.5, 5.2; CLR, OR: 2.81, 95% CI: 1.1, 7.3), whereas dogs receiving prescription anti-inflammatory medications were found to be at considerably lower risk of developing HS (MELR, OR: 0.42, 95% CI: 0.2, 0.8; CLR, OR: 0.32, 95% CI: 0.1, 0.8).

CONCLUSIONS AND CLINICAL IMPORTANCE

These results suggest inflammation may be a modifiable risk factor for the development of HS in BMD.

Prevalence of antibodies against Borrelia burgdorferi, Anaplasma phagocytophilum, and Leptospira interrogans serovars in Bernese Mountain Dogs

OBJECTIVE

Bernese Mountain Dogs (BMD) have a higher prevalence of Borrelia burgdorferi sensu lato (Bbsl) antibodies than other breeds, but it is not known whether this is the case for other pathogens. Therefore, the aim of the study was to determine the frequency and level of specific antibodies against members of the Bbsl group, Anaplasma phagocytophilum (Ap), and Leptospira (L.) interrogans serovars in BMD and compare the results with those found in dogs of other breeds.

MATERIALS AND METHODS

A total of 171 healthy BMD and 57 healthy control dogs of other breeds were included in the study. Controls were large dogs (> 30 kg) with long, dark hair coats. A two-tiered testing method consisting of computerized kinetic enzyme-linked immunosorbent assay (KELA) and Western blotting was used for detection of antibodies against Bbsl, an immunofluorescence assay (IFA) was used for detection of antibodies against Ap, and microscopic agglutination test (MAT) for antibodies to 18 different serovars of L. interrogans.

RESULTS

The prevalence of anti-Bbsl antibodies was significantly higher in BMD (43.3%) than in controls (17.5%) (p < 0.001). Antibodies to Bbsl attributable to vaccination were excluded from the calculation of prevalence. Antibodies to Ap were found in 50.3% of BMD, whereas only 24.6% of the controls dogs were tested positive for Ap (p < 0.001). Antibody titers of the 18 different serovars of L. interrogans antibodies did not differ significantly between BMD and control dogs except for L. copenhageni antibody titers which were higher in BMD. Significantly higher antibody titers to L. canicola (p = 0.003), L. copenhageni (p = 0.005), L. grippothyphosa (p = 0.029) and L. vanderhoedoni (p = 0.035) were seen in BMD compared to control dogs.

CONCLUSION AND CLINICAL RELEVANCE

BMD had a higher prevalence of anti-Bbsl, anti-L. copenhageni and anti-Ap antibodies than control dogs. Significantly higher antibody titers against L. canicola (p = 0.003), L. copenhageni (p = 0.005), L. grippothyphosa (p = 0.029) and L. vanderhoedoni (p = 0.035) were seen in BMD compared with control dogs, but the reason for this and potential clinical implications are not known.

A review of histiocytic diseases of dogs and cats

Histiocytic proliferative disorders are commonly observed in dogs and less often cats. Histiocytic disorders occur in most of the dendritic cell (DC) lineages. Canine cutaneous histiocytoma originates from Langerhans cells (LCs) indicated by expression of CD1a, CD11c/CD18, and E-cadherin. When histiocytomas occur as multiple lesions in skin with optional metastasis to lymph nodes and internal organs, the disease resembles cutaneous Langerhans cell histiocytosis of humans. Langerhans cell disorders do not occur in feline skin. Feline pulmonary LCH has been recognized as a cause of respiratory failure due to diffuse pulmonary infiltration by histiocytes, which express CD18 and E-cadherin and contain Birbeck's granules. In dogs and cats, histiocytic sarcomas (HS) arise from interstitial DCs that occur in most tissues of the body. Histiocytic sarcomas begin as localized lesions, which rapidly disseminate to many organs. Primary sites include spleen, lung, skin, brain (meninges), lymph node, bone marrow, and synovial tissues of limbs. An indolent form of localized HS, progressive histiocytosis, originates in the skin of cats. Hemophagocytic HS originates in splenic red pulp and bone marrow macrophages in dogs and cats. In dogs, histiocytes in hemophagocytic HS express CD11d/CD18, which is a leuko-integrin highly expressed by macrophages in splenic red pulp and bone marrow. Canine reactive histiocytic diseases, systemic histiocytosis (SH) and cutaneous histiocytosis, are complex inflammatory diseases with underlying immune dysregulation. The lesions are dominated by activated interstitial DCs and lymphocytes, which invade vessel walls and extend as vasocentric infiltrates in skin, lymph nodes, and internal organs (SH).

Histiocytic sarcoma with central nervous system involvement in dogs: 19 cases (2006-2012)

Background

Reports of histiocytic sarcoma (HS) involving the central nervous system (CNS) are sparse and consist mainly of case reports describing 1–3 animals.

Objective

The objective of this study was to report the signalments, clinical signs, clinicopathologic and diagnostic imaging findings, treatment, and outcome of a series of dogs with HS and CNS involvement.

Animals

Nineteen dogs with HS examined at veterinary referral hospitals.

Methods

Retrospective case series. Medical records were reviewed and cases with a histopathological diagnosis of CNS HS were included in the study. Diagnostic imaging studies of the CNS were evaluated and histopathologic samples were reviewed to confirm the diagnosis.

Results

Retrievers and Pembroke Welsh Corgis were overrepresented in this cohort of dogs. Tumors involved the brain in 14 dogs and the spinal cord in 5. In 4 dogs, HS was part of a disseminated, multiorgan process whereas it appeared confined to the CNS in 15 dogs. Diagnostic imaging had variable appearances although extraaxial masses predominated in the brain. There was meningeal enhancement in all dogs that was often profound and remote from the primary mass lesion. Pleocytosis was present in all dogs with CSF evaluation. Median survival was 3 days.

Conclusions and Clinical Importance

Breed predispositions appear to vary from reports of HS in other organ systems. Some unique imaging and clinicopathologic characteristics, particularly brain herniation, profound meningeal enhancement, and pleocytosis in combination with 1 or more mass lesions, might help to differentiate this neoplasm from others involving the CNS, although this requires further study.

Evaluation of the drug sensitivity and expression of 16 drug resistance-related genes in canine histiocytic sarcoma cell lines

Canine histiocytic sarcoma (HS) is an aggressive tumor type originating from histiocytic cell lineages. This disease is characterized by poor response to chemotherapy and short survival time. Therefore, it is of critical importance to identify and develop effective antitumor drugs against HS. The objectives of this study were to examine the drug sensitivities of 10 antitumor drugs. Using a real-time RT-PCR system, the mRNA expression levels of 16 genes related to drug resistance in 4 canine HS cell lines established from dogs with disseminated HS were determined and compared to 2 canine lymphoma cell lines (B-cell and T-cell). These 4 canine HS cell lines showed sensitivities toward microtubule inhibitors (vincristine, vinblastine and paclitaxel), comparable to those in the canine B-cell lymphoma cell line. Moreover, it was shown that P-gp in the HS cell lines used in this study did not have enough function to efflux its substrate. Sensitivities to melphalan, nimustine, methotrexate, cytarabine, doxorubicin and etoposide were lower in the 4 HS cell lines than in the 2 canine lymphoma cell lines. The data obtained in this study using cultured cell lines could prove helpful in the developing of advanced and effective chemotherapies for treating dogs that are suffering from HS.

Safety, tolerability and pharmacokinetic properties of the novel triazene TriN 2755 in tumour bearing dogs - a phase I study†

TriN 2755 is an alkylating antineoplastic agent for intravenous (IV) use, carrying the triazene group as the cytotoxic principal. Using a standard 3 + 3 design, a phase I study was performed in tumour bearing dogs to determine the maximum tolerated dose (MTD), the dose limiting toxicity (DLT), and pharmacokinetic (PK) profile of TriN 2755. Thirty dogs were included in the study. TriN 2755 was administered over 20 min on two consecutive weeks per month for a total of three cycles. The starting dose was 25 mg kg^-1 and the MTD was 74.6 mg kg^-1 . Three dogs experienced DLT, which was characterized by gastrointestinal adverse events. The PKs of TriN 2755 and its main metabolites in plasma and sputum are described in a two-compartment model. The response rate for 19 of 30 dogs was 47.3% (six partial remission, three stable disease) and the median progression-free interval (PFI) for the responders was 47 days (range: 21-450 days).

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.

Clinical characteristics and prognostic factors in dogs with histiocytic sarcomas in Japan

Canine histiocytic sarcoma (HS) is a rare neoplasm that originates from dendritic cells or macrophages, and there have been a number of cases experienced in Japan. To identify the characteristics and prognostic variables that determine outcome in dogs with HS in Japan, medical records of 73 dogs with HS were retrospectively analyzed. Signalment, clinical signs, complete blood count (CBC), blood chemistry profiles, treatment, response to treatment and overall survival (OS) were analyzed. Diagnosis of HS was determined histologically in 44 cases and cytologically in 29 cases. The most frequently diagnosed breeds were Flat-Coated Retrievers (n=16, odds ratio [OR] 62.0), Pembroke Welsh corgis (n=15, OR 9.7) and Bernese Mountain dogs (n=14, OR 45.0). Median survival time for all dogs in this study was 43 days. In the dogs that received no treatment or only symptomatic treatment, the median OS was 12 days (range 2–254 days) compared with that of dogs that received surgical treatment and/or chemotherapy (85 days, range 4–360 days). Univariate analysis identified anemia, thrombocytopenia, hypoalbuminemia, hypoproteinemia and not receiving antitumor treatment (chemotherapy and/or surgery) as factors significantly associated with shorter OS. Multivariate analysis confirmed that platelet counts, localized/disseminated lesional pattern and whether the dog received antitumor treatment were significantly predictive of survival.

Causes of death and the impact of histiocytic sarcoma on the life expectancy of the Dutch population of Bernese mountain dogs and Flat-coated retrievers

Bernese mountain dogs and Flat-coated retrievers are predisposed to hereditary oncological diseases. Since 1986 several authors have reported a high prevalence of tumours in both breeds, especially malignant histiocytosis/histiocytic sarcoma, which has a negative influence on life expectancy. However, many earlier reports included relatively low numbers of dogs, distributed over a small number of broad categories, often using outdated disease criteria. The aim of this study was to provide new data on causes of death, and the relative role of tumours, especially histiocytic sarcoma, collected and verified in a large number of dogs of both breeds in co-operation with dog owners and veterinarians. The study demonstrates that the death of at least 55.1% of Bernese mountain dogs and 63.8% of Flat-coated retrievers is associated with malignant tumours. In addition, it appears that over 1/7 of all Bernese mountain dogs and Flat-coated retrievers die because of histiocytic sarcoma. This emphasises the need for further research on tumours, especially histiocytic sarcoma.

Peri-articular histiocytic sarcoma and previous joint disease in Bernese Mountain Dogs

BACKGROUND

Peri-articular histiocytic sarcoma (PAHS) occurs in dogs, including Bernese Mountain Dogs (BMD). An etiologic relationship with previous joint disease has not been documented.

HYPOTHESIS

Peri-articular histiocytic sarcoma in BMD will be more frequently encountered around previously diseased joints compared with normal joints.

ANIMALS

920 European BMD.

METHODS

A retrospective study, in which data were obtained through an Internet questionnaire and from 2 veterinary pathology laboratories. Archived samples of hematoxylin-eosin (H&E) staining diagnosed PAHS and synovial cell sarcoma (SCS) were immunolabeled with CD18 and pancytokeratin. Descriptive, comparative, and actuarial statistics comprise the data analysis.

RESULTS

All primary synovial tumors were identified as PAHS based on their morphology, positive CD18, and negative pancytokeratin labeling. Joint disease was diagnosed in 226 BMD, of which 15 developed PAHS in a previously diseased joint and 3 in a nondiseased joint. Of the remaining 694 BMD without joint disease, 9 developed PAHS. The odds ratio for a dog with previous joint disease developing PAHS is calculated as 5.4 (95% CI: 2.3-12.5; P < .0001) compared with no previous joint problem. A significant association between previous joint disease and PAHS in the same joint was demonstrated for the left elbow (P = .016), right elbow (P = .006), right shoulder (P = .047), left and right stifle (P < .001), and left carpal joint (P = .010).

CONCLUSIONS AND CLINICAL IMPORTANCE

The results of this study suggest a relation between previous joint disease and the development of PAHS in the same joint of European BMD. Owners of BMD should monitor dogs for peri-articular swellings, particularly around previously diseased joints.

Cytopathological diagnosis of visceral histiocytic sarcoma in five dogs

Histiocytic sarcoma is a malignant neoplastic proliferation of atypical histiocytes with tendency to spread, characterized by fast progression to disseminated form--disseminated histiocytic sarcoma. Cytopathology is a low, invasive, cheap, and quick method of diagnosis commonly used in veterinary oncology. The aim of the presented study was description of cases of visceral histiocytic sarcomas in dogs diagnosed by cytopathology and immunocytochemistry. The study was conducted on 5 dogs which were brought to the veterinary clinic because of unspecific clinical signs and tumoral masses recognized in the thoracic or abdominal cavity. Samples of cells were collected during ultrasonography-assisted fine-needle aspiration biopsy (FNAB), smears were stained with Giemsa method and immunocytochemistry (CD3, CD79alpha, cytokeratin, vimentin, desmin) was also performed in all patients. Four of five dogs were Bernese mountain dogs, nonspecific clinical signs of systemic disease were present in all cases. Visceral mass or masses were detected by ultrasonography or radiography. Final diagnosis of histiocytic sarcoma was obtained on the basis of routine cytopathological examination and confirmed by immunocytochemistry. On the basis the results obtained it can be stated that in cases of typical clinical and cytopathologic pictures, examination of cellular samples collected during ultrasonography-assisted fine-needle biopsy supported by some immunocytopathological characteristics seems to be sufficient method of diagnosis of histiocytic sarcoma in dogs. Visceral histiocytic sarcoma should be included into differential diagnosis in every Bernese mountain dog with nonspecific clinical signs, ambiguous results of hematologic examination and when tumoral mass or masses within a body cavity were detected in imaging techniques.

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.

Molecular cytogenetic characterization of canine histiocytic sarcoma: A spontaneous model for human histiocytic cancer identifies deletion of tumor suppressor genes and highlights influence of genetic background on tumor behavior

Background

Histiocytic malignancies in both humans and dogs are rare and poorly understood. While canine histiocytic sarcoma (HS) is uncommon in the general domestic dog population, there is a strikingly high incidence in a subset of breeds, suggesting heritable predisposition. Molecular cytogenetic profiling of canine HS in these breeds would serve to reveal recurrent DNA copy number aberrations (CNAs) that are breed and/or tumor associated, as well as defining those shared with human HS. This process would identify evolutionarily conserved cytogenetic changes to highlight regions of particular importance to HS biology.

Methods

Using genome wide array comparative genomic hybridization we assessed CNAs in 104 spontaneously occurring HS from two breeds of dog exhibiting a particularly elevated incidence of this tumor, the Bernese Mountain Dog and Flat-Coated Retriever. Recurrent CNAs were evaluated further by multicolor fluorescence in situ hybridization and loss of heterozygosity analyses. Statistical analyses were performed to identify CNAs associated with tumor location and breed.

Results

Almost all recurrent CNAs identified in this study were shared between the two breeds, suggesting that they are associated more with the cancer phenotype than with breed. A subset of recurrent genomic imbalances suggested involvement of known cancer associated genes in HS pathogenesis, including deletions of the tumor suppressor genes CDKN2A/B, RB1 and PTEN. A small number of aberrations were unique to each breed, implying that they may contribute to the major differences in tumor location evident in these two breeds. The most highly recurrent canine CNAs revealed in this study are evolutionarily conserved with those reported in human histiocytic proliferations, suggesting that human and dog HS share a conserved pathogenesis.

Conclusions

The breed associated clinical features and DNA copy number aberrations exhibited by canine HS offer a valuable model for the human counterpart, providing additional evidence towards elucidation of the pathophysiological and genetic mechanisms associated with histiocytic malignancies. Extrapolation of data derived from canine histiocytic disorders to human histiocytic proliferation may help to further our understanding of the propagation and cancerization of histiocytic cells, contributing to development of new and effective therapeutic modalities for both species.

Malignant histiocytosis and other causes of death in Bernese mountain dogs in Denmark

To determine the causes of death in Bernese mountain dogs, to assess the prevalence of malignant histiocytosis in the Danish Bernese mountain dog population, and to assess whether a hereditary pattern for this disease exists, 756 questionnaires were sent to members of the Danish Bernese Mountain Dog Club requesting information regarding the life span and causes of death of their dogs. A response rate of 57.7 per cent was achieved, giving information for 812 dogs, of which 290 had died. The average life span was 7.1 years. The most prevalent causes of death were neoplasia (42.1 per cent), old age (10.3 per cent), kidney disease (6.9 per cent), infection (5.9 per cent), skeletal problems (5.2 per cent), heart disease (3.8 per cent) and behavioural causes (3.5 per cent). Thirteen dogs were diagnosed with malignant histiocytosis, 11 of which were genealogically related.

Multiple distinct malignancies in dogs: 53 cases

Despite the clinical recognition of multiple distinct types of neoplasia in individual dogs, a detailed description of such cases has not recently been published. Canine oncology cases that were diagnosed with multiple, confirmed, distinct malignancies were prospectively collected for analysis. Approximately 3% of 1722 dogs that were presented to the oncology service at the Colorado State University Veterinary Medical Center were diagnosed with multiple distinct primary tumors. No significant breed or sex predisposition was apparent. Dogs with mast cell tumor, malignant melanoma, and thyroid carcinoma were significantly overrepresented and thus more likely to be diagnosed with multiple tumor types. These findings emphasize the importance of thorough, whole-body evaluation for dogs presented with mast cell tumor, malignant melanoma, and thyroid carcinoma. Furthermore, because approximately 33% of dogs that were presented with thyroid tumors were found to have additional distinct tumors, complete staging is justified in all dogs presented with thyroid tumors.

Langerhans cell histiocytosis: malignancy or inflammatory disorder doing a great job of imitating one?

Langerhans cell histiocytosis (LCH) is the unifying designation for a rare proliferative disorder that occurs predominantly in childhood and involves the main antigen-presenting cell of the epidermis. LCH can present in a multitude of ways, from a self-limited rash that resolves spontaneously to a systemic multi-organ disease with a 20% mortality rate. Because some forms behave in a relatively benign manner and are associated with an inflammatory cell infiltrate, it has been proposed that LCH might be a reactive disease. However, its neoplastic nature is suggested by the fact that the proliferating cells in LCH are clonal and overexpress p53. Nonetheless, no recurrent genomic, genetic or epigenetic abnormalities have been identified. Instead, a variety of molecular abnormalities that are consistent with disordered Langerhans cell maturation have been described. A faithful small animal model would aid our understanding of the pathophysiology of LCH but, to date, none exists. Challenges to the creation of a model include the lack of characteristically recurrent genetic abnormalities and the absence of a truly tissue-specific promoter to drive expression of genetic elements solely in Langerhans cells. Still, some of the phenotypic abnormalities in adhesion molecule or chemokine receptor expression might be modeled with sufficient precision to allow the testing of novel therapies.

Breed, gender and neutering status of British dogs with anal sac gland carcinoma

This study details the breed, gender and neutering status of a large cohort of British canine patients suffering from histologically confirmed anal sac gland carcinoma. Estimates of the relative risk for the development of this disease attributable to these factors are calculated. To reduce the impact of sampling errors, cases were selected from veterinary histopathology laboratories rather than referral hospital databases, and multiple estimates of the general British canine population were used. The weaknesses of the statistical assumptions made are discussed. There was no evidence to support a gender predisposition for the development of this condition. English cocker spaniels are significantly over-represented, with a mean relative risk estimate of 7.3. The mean relative risk estimate associated with being neutered was 1.4; the effect of neutering appeared to be more significant in male dogs compared with that in female dogs.

Epidemiology, pathology, and genetics of histiocytic sarcoma in the Bernese mountain dog breed

Histiocytic sarcoma (HS) refers to a highly aggressive and frequently disseminated neoplastic disease belonging to the class of canine histiocytic proliferative disorders. Disseminated HS (previously called malignant histiocytosis) is highly breed specific, with Bernese mountain dogs (BMDs), rottweilers, and retrievers having a high prevalence with a frequency of approximately 25% in the BMD breed. We collected DNA samples and clinical information from 800 BMDs, of which 200 are affected by HS. To better characterize the physiopathology and epidemiology, an in-depth analysis of 89 BMD cases has been performed. The mean age of onset was 6.5 years, males and females being equally affected. The clinical features, biochemical parameters, and pathological features have been determined. The life span after diagnosis has been estimated to be 49 days. A large BMD pedigree of 327 dogs, 121 of which are affected, was assembled. Using a subset of 160 BMDs, encompassing 21 complete sibships, we now propose an oligogenic transmission mode of the disease. Whole-genome linkage scans as well as association studies using a case/control analysis, in parallel with expression profiling of neoplastic versus normal histiocytes, are all underway. Altogether, these complementary approaches are expected to localize the genes for HS in the BMD, leading to advances in our knowledge of histiocyte diseases in dogs and humans.

Increased prevalence of Borrelia burgdorferi infections in Bernese Mountain Dogs: a possible breed predisposition

Background

Glomerulonephritis in dogs has been associated with B. burgdorferi infections. In Bernese Mountain Dogs with glomerulonephritis antibodies against B. burgdorferi have been found in most dogs, raising the question if the breed is predisposed to infections with B. burgdorferi. The aim of this study was to determine the prevalence of antibodies against B. burgdorferi sensu lato in a well defined population of Bernese Mountain Dogs and to compare this prevalence with data from dogs of other breeds.

Results

160 Bernese Mountain Dogs and 62 control dogs (large breed dogs with long hair) were included. All dogs were considered healthy according to a questionnaire filled out by the owner, complete blood count, chemistry panel, urinalysis and urine culture. Bernese Mountain Dogs and control dogs were kept in similar environments. Seroprevalence of B. burgdorferi was assessed by ELISA and Western blot and was 58% in Bernese Mountain Dogs compared to 15% in control dogs. This difference was significant. Neither antibodies against leptospires nor vaccination or hair coat color influenced the results.

Conclusion

The cause of the considerably higher prevalence of antibodies against B. burgdorferi in Bernese Mountain Dogs and it's consequences are not known. A breed predisposition can be suspected.

Heritability and segregation analysis of osteosarcoma in the Scottish deerhound

Osteosarcoma is the most common malignant bone tumor in dogs and, like its human orthologue, is characterized by aggressive local behavior and high metastatic rates. The Scottish deerhound is a breed of dog with a >15% incidence of osteosarcoma and represents an excellent spontaneously occurring large-animal model of the human disease. We modeled the transmission of the osteosarcoma phenotype in a population of over 1000 related deerhounds ascertained as part of a prospective health study. Variance component analysis, segregation analysis, and linear modeling were performed to evaluate heritability, to infer the presumptive transmission model, and to identify covariate effects for this phenotype within the breed, respectively. Based on variance component analysis, heritability (h2) was estimated to be 0.69. Six transmission models were analyzed by segregation analysis; based on Akaike's information criteria, the most parsimonious model was the Mendelian major gene model with dominant expression. Linear modeling identified gender and genotype as significant predictors of disease outcome. Importantly, duration of gonadal hormone exposure, weight, and height at maturity were not significant predictors of outcome. Inheritance of the putative high-risk allele was thus associated with >75% risk of disease occurrence compared to the <5% baseline risk. These results support the hypothesis that a major gene with a dominant effect explains most of the osteosarcoma phenotype within the Scottish deerhound.

Evaluation of dysregulation of the receptor tyrosine kinases Kit, Flt3, and Met in histiocytic sarcomas of dogs

OBJECTIVE

To evaluate canine histiocytic sarcoma cell lines and tumor samples for dysregulation of the Kit/stem-cell factor (SCF), Flt3/Flt3 ligand (Flt3L), and Met/hepatocyte growth factor (HGF) receptor tyrosine kinase signaling pathways, as these are known to contribute to the differentiation and survival of normal dendritic cells as well as malignant transformation of dendritic cells in mouse models.

SAMPLE POPULATION

4 histiocytic sarcoma tumor cell lines and 35 formalin-fixed histiocytic sarcoma specimens obtained from dogs.

PROCEDURE

Histiocytic sarcoma cell lines were evaluated for expression of Kit/SCF, Flt3/Flt3L, and Met/HGF by use of reverse transcriptase-PCR procedures. Histiocytic sarcoma cell lines and tumor samples were evaluated for mutations in Kit, Flt3, and Met by use of PCR analysis of genomic DNA, followed by both sequencing and fluorescent PAGE for deletions or internal tandem duplications. The ability of the multi-targeted split-kinase inhibitor SU11654 to block proliferation and induce apoptosis of histiocytic sarcoma cell lines was also evaluated.

RESULTS

No mutations in Kit, Flt3, and Met were identified in any of the cell lines or tumor samples evaluated. Furthermore, SU11654 did not induce cell-cycle arrest or apoptosis of histiocytic sarcoma lines, even at supratherapeutic doses.

CONCLUSIONS AND CLINICAL RELEVANCE

These data suggest that dysregulation of Kit/SCF, Flt3/Flt3L, and Met/HGF signaling pathways is unlikely to occur in histiocytic sarcomas of dogs and that inhibitors of the Kit, Flt3, and Met pathways are unlikely to provide clinical benefit to dogs with histiocytic sarcomas.

SONOGRAPHIC FEATURES OF HISTIOCYTIC NEOPLASMS IN THE CANINE ABDOMEN

The purpose of this retrospective study was to describe the ultrasonographic features of malignant histiocytosis (MH), malignant fibrous histiocytoma, and histiocytic sarcoma in abdominal organs of dogs. The medical records of 18 dogs that had undergone abdominal sonography and had a histopathologic diagnosis of abdominal MH, malignant fibrous histiocytoma, and histiocytic sarcoma were reviewed. The organ most commonly affected was the spleen. MH was the most common followed by histiocytic sarcoma and malignant fibrous histiocytoma. In the spleen there were often multiple hypoechoic nodules with well-defined borders. In one dog, without focal lesions, the spleen was enlarged and hypoechoic. The liver was the second most commonly affected organ. MH was most common followed by histiocytic sarcomas and malignant fibrous histiocytoma. The most common sonographic feature in the liver was the presence of multiple hypoechoic nodules with well-defined borders. One dog without hepatic nodules had a liver that was ultrasonographically enlarged and hypoechoic. MH in the abdominal lymph nodes resulted in hypoechoic lymphadenopathy. Malignant fibrous histiocytoma was the only neoplastic type in the kidneys appearing as a single heteroechoic renal mass with well-defined borders. MH was observed in the stomach of one dog. Sonographically there was a single well circumscribed hypoechoic mass with well-defined borders and abnormal stomach layers. In this study it was not possible to differentiate between MH, malignant fibrous histiocytoma, and histiocytic sarcoma using sonography.

Malignant histiocytosis in three Bernese mountain dogs

Malignant histiocytosis is a rare disease which is characterised by the neoplastic proliferation of tissue macrophages (histiocytes) leading to excessive phagocytosis of erythrocytes. The clinical signs and pathological findings in three Bernese mountain dogs are described. Two of the dogs had the same sire. The disease has been established as a familial problem in Bernese mountain dogs in other countries, although it has not been previously recorded in the United Kingdom.