Fusariosis in Mexico: A 10-year retrospective series.

Fusarium species represent an opportunistic fungal pathogen. The data in Mexico about Fusarium infections in humans are scarce. Here, we present a retrospective series of patients with a confirmed diagnosis of fusariosis in eight different hospitals in Mexico from January 2010 to December 2019. The diagnosis of proven fusariosis was made according to the European Organization for Research and Treatment of Cancer and the Mycoses Study Group Education and Research Consortium (EORT/MSG) criteria. A total of 49 cases were identified in our series. Most patients had burn injuries (49%), and 37% had hematological malignancies. Most patients had fire injuries (40%), followed by electric injuries (8%), febrile neutropenia (10%), and pancytopenia (6%). Patients had skin and soft tissue involvement in 49%, followed by blood culture isolation and biopsies from different sites of the body (lung, sinuses, bone tissue, and eyes). Febrile neutropenia (10%) and fungemia (8%) were the most common clinical syndromes in immunosuppressed patients. Most patients received monotherapy (67%), where voriconazole was used in 30% of the cases, followed by conventional amphotericin B (16%), and lipidic formulations of amphotericin B in 10% (either liposomal amphotericin B or amphotericin B lipid complex). Combination therapy was used in 20% of the cases, and the most common combination therapy was triazole plus any lipidic formulation of amphotericin B (10%). Mortality related to Fusarium infection occurred in 22% of patients. Fusariosis is a serious threat. Burn injuries and hematologic malignancies represent the most common causes of infection in this small series from Mexico.

This study describes the epidemiological characteristics of patients with fusariosis from a multicenter cohort in Mexico. These findings provide information from this invasive fungal disease that threatens different countries in Latin America.

Antemortem cytologic diagnosis of pulmonary Langerhans cell histiocytosis in a cat.

Feline pulmonary Langerhans cell histiocytosis (FPLCH) is a rare histiocytic proliferative disease of middle-aged to older domestic cats. Langerhans cells in the terminal airways proliferate and infiltrate the interstitium and the airways to a lesser degree, widely effacing normal parenchyma. Historically, definitive diagnosis has required postmortem evaluation where pulmonary lesions have a classic gross and histologic morphology. Here, we present the first documented antemortem diagnosis of FPLCH using bronchoalveolar lavage (BAL) cytology and immunocytochemistry (ICC) in a 9-year-old British shorthair mix. The cat had a 3-month history of respiratory difficulty that was refractory to steroids and antimicrobials. Pulmonary radiographs had marked diffuse changes with a complex bronchointerstitial and micronodular pattern. BAL cytology revealed neutrophilic inflammation and markedly increased histiocytes with morphology distinct from typical pulmonary macrophages. ICC characterized histiocytes as CD1a+ /E-cadherin+ /CD11b- /PanCK- , consistent with a Langerhans cell phenotype. The cat was humanely euthanized due to poor prognosis and presented for necropsy. Gross, histopathologic, immunophenotypic, and ultrastructural findings confirmed a diagnosis of FPLCH. Proliferative cells were E-cadherin+ /Iba-1+ /CD18+ /CD1a+ /CD5+ /MHCII+ /CD204- /CD4- ; transmission electron microscopy identified the presence of Birbeck granules in the proliferating histiocytes, consistent with previous reports of FPLCH.

Monitoring plasma nucleosome concentrations to measure disease response and progression in dogs with hematopoietic malignancies.

BACKGROUND: Hematopoietic malignancies are extremely common in pet dogs and represent nearly 30% of the malignancies diagnosed in this population each year. Clinicians commonly use existing tools such as physical exam findings, radiographs, ultrasound and baseline blood work to monitor these patients for treatment response and remission. Circulating biomarkers, such as prostate specific antigen or carcinoembryonic antigen, can be useful tools for monitoring treatment response and remission status in human cancer patients. To date, there has a been a lack of useful circulating biomarkers available to veterinary oncology patients. METHODS: Circulating plasma nucleosome concentrations were evaluated at diagnosis, throughout treatment and during remission monitoring for 40 dogs with lymphoma, acute myelogenous leukemia and multiple myeloma. Additionally, C-reactive protein and thymidine kinase-1 levels were recorded. RESULTS: Plasma nucleosome concentrations were significantly higher at diagnosis and progressive disease than they were when dogs were in remission. All but two dogs had plasma nucleosome concentrations that returned to the low range during treatment. These two dogs had the shortest progression free and overall survival times. Dogs with the highest plasma nucleosome concentrations had a significantly shorter first progression free survival than dogs with lower plasma nucleosome concentrations at diagnosis. Plasma nucleosome concentrations correlated better with disease response and progression than either thymidine kinase or C reactive protein. CONCLUSIONS: Plasma nucleosome concentrations can be a useful tool for treatment monitoring and disease progression in dogs with hematopoietic malignancies.

Sensitivity of canine hematological cancers to BH3 mimetics.

BACKGROUND: Inhibition of antiapoptotic B-cell lymphoma 2 (BCL2) proteins by small molecule Bcl-2 homology 3 (BH3) mimetics causes rapid induction of apoptosis of human hematological cancers in vitro and in vivo. OBJECTIVES: Assess in vitro sensitivity of non-neoplastic lymphocytes and primary hematological cancer cells from dogs to venetoclax (VEN) or the dual BCL2/ B-cell lymphoma-extra-large (BCLxL) inhibitor, navitoclax (NAV), and evaluate the association between BCL2 protein expression and VEN sensitivity. ANIMALS: Nine client-owned dogs without cancer and 18 client-owned dogs with hematological cancer. METHODS: Prospective, nonrandomized noncontrolled study. Lymphocytes isolated from peripheral blood, lymph node, or bone marrow from dogs were incubated with BH3 mimetics for 24 hours. Viable cells were counted using flow cytometry and half maximal effective concentration (EC50 ) was calculated. BCL2 protein from whole cell lysates was assessed via immunoblots. RESULTS: Nodal B and T lymphocytes were more sensitive to VEN than circulating lymphocytes (P = .02). Neoplastic T lymphocytes were sensitive to VEN (mean EC50 ± SD = 0.023 ± 0.018 µM), whereas most non-indolent B cell cancers were resistant to killing by VEN (mean EC50 ± SD = 288 ± 700 µM). Unclassified leukemias showed variable sensitivity to VEN (mean EC50 ± SD = 0.49 ± 0.66 µM). Detection of BCL2 protein was not associated with VEN sensitivity. CONCLUSION AND CLINICAL IMPORTANCE: Neoplastic canine T lymphocytes are sensitive to VEN in vitro. Quantification of BCL2 protein alone is insufficient to predict sensitivity to VEN.

Granular variant of a histiocytic tumor on the toe of a cat: Case report and literature review.

A 16-year-old female spayed domestic shorthaired cat was examined for lameness and a mass on the fourth digit of the right hindlimb. Cytologic examination of an aspirate of the mass revealed large discrete cells admixed with low numbers of well-granulated mast cells. The discrete cells contained single to many variably sized light pink to purple granules in their cytoplasm and had pleomorphic nuclei, with intranuclear cytoplasmic inclusions. Karyomegalic, binucleated and multinucleated cells were seen. Histologic examination of formalin-fixed sections of the excised mass showed a mildly infiltrative, unencapsulated, multinodular dermal mass that extended into the subcutis and consisted of similar discrete cells. On immunohistochemical staining, the tumor cells expressed ionized calcium-binding adapter molecule 1 (Iba1) and CD18. The tumor cells did not express CD3, CD20, CD117, pancytokeratin (AE1/AE3), melanoma antigen (Melan-A), multiple myeloma oncogene-1 (MUM1), melanoma-associated antigen (PNL-2), and S-100. Low numbers of tumor cells expressed CD204 and protein gene product 9.5 (PGP9.5). Granules were variably positive for Periodic-acid Schiff (PAS) and Alcian blue. On transmission electron microscopy, the cells contained filopodia, abundant endoplasmic reticulum, and moderate numbers of low-density membrane-bound granules. This case documents a previously undescribed granular variant of a histiocytic tumor in a cat.

Incidence of invasive fungal infections in patients with hematological malignancies receiving ibrutinib therapy in south-east Austria.

Since the broad implementation of ibrutinib therapy, an increasing number of studies have been reported on invasive fungal infections (IFI) associated with ibrutinib administration. We conducted a retrospective cohort study in three hospitals in south-east Austria in order to assess the local epidemiology of ibrutinib associated IFIs. A total of 113 patients with underlying hematological malignancy were included in the study. During the study period, a single IFI episode was observed, which corresponds to an IFI incidence of 2.3 cases per 100 person years (95% CI: 0.12-11.47). IFIs during ibrutinib therapy seem to be a rare event in case of absent additional risk factors for IFIs.

Ibrutinib is an effective drug used to treat a variety of blood cancers, but it might increase risk for life-threatening invasive fungal infections (IFIs). In our study, a low number (1 IFI per 43 patient years) of patients on ibrutinib developed an IFI.

Bite-size introduction to canine hematologic malignancies.

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

Investigation of platelet measurands in dogs with hematologic neoplasia.

INTRODUCTION: Thrombocytopenia has been associated with some neoplastic processes, including hematologic neoplasia. There is no information regarding specific changes in platelet measurands in dogs with hematologic neoplasia compared with healthy dogs. The objectives of our study were to establish RIs, evaluate platelet measurands in dogs with hematologic neoplasia, and compare these measurands in patients with hematologic malignancies with or without thrombocytopenia. METHODS: This was a retrospective study. Platelet measurands were determined using the ADVIA 120 Hematology analyzer when a CBC was performed and included the platelet count, MPV, platelet distribution width (PDW), plateletcrit (PCT), mean platelet component (MPC), platelet component distribution width (PCDW), mean platelet mass (MPM), platelet mass distribution width (PMDW), and number of large platelets. Reference intervals were determined retrospectively using data from 129 healthy dogs. Patients with hematologic neoplasia (n = 50) were identified through retrospective evaluation of medical records from the Auburn University Veterinary Teaching Hospital and separated into thrombocytopenic (n = 20) and nonthrombocytopenic groups (n = 30). RESULTS: Platelet count and PCT were significantly higher in older healthy dogs compared with younger dogs. Significant differences were identified when comparing healthy dogs with those with hematologic neoplasia without thrombocytopenia for PDW, PCDW, PMDW, and the number of large platelets, indicating the presence of more heterogeneous platelets. Thrombocytopenic dogs with hematologic neoplasia had significantly decreased MPCs and increased MPVs, MPMs, and PCDWs compared with nonthrombocytopenic dogs with neoplasia. CONCLUSIONS: Dogs with hematologic neoplasia had more heterogeneous platelets, whereas thrombocytopenic patients with neoplasia had more activated platelets.

Geotrichum spp: An overlooked and fatal etiologic agent in immunocompromised patients. A case series from a referral center in Mexico.

Geotrichum spp. is an emergent pathogen. We aimed to describe Geotrichum spp. invasive fungal infections (IFI) in patients from Mexico. We reviewed cases with Geotrichum spp. isolated in clinical samples, from 2001 to 2019. Descriptive analysis was used for clinical data. Twenty patients with proven/probable Geotrichum spp. IFI were analyzed. The median age was 43; 55% were males. Hematologic malignancy was found in 60% (12/20); 75% (15/20) received systemic immunosuppressors. The most common presentation was lower respiratory tract infection. In-hospital mortality was 45% (9/20). Geotrichum spp. should be acknowledged as a pathogen causing atypical pneumonia in immunocompromised Latin American patients. LAY SUMMARY: Geotrichum spp. causes invasive infection in immunocompromised hosts. We describe a case series of 20 patients from Mexico City. Hematologic malignancy was the most common comorbidity. Clinical presentation was mainly lower respiratory tract infection. Mortality was high despite antifungal therapy.

Serum TK1 protein and C-reactive protein correlate to treatment response and predict survival in dogs with hematologic malignancies.

Thymidine kinase 1 (TK1), involved in DNA precursor synthesis, is used as a serum biomarker in cancer diagnostics in both human and veterinary medicine. We investigated the utility of serum TK1 protein (TK1p) and TK1 activity (TK1a) determinations for prognosis and monitoring of canine hematological malignancies. The combination of TK1p or TK1a with canine C-reactive protein (CRP) determinations was also investigated. Serum samples from 51 client-owned dogs with naive hematological malignancies and from 149 healthy subjects were included. Serum TK1p levels were determined using a prototype TK1-ELISA, TK1a using the [3H]-dThd phosphorylation assay, and CRP using an immunoturbidimetric assay. Mean TK1p in sera from dogs with tumors was significantly higher than from healthy dogs (mean ± SD = 3.9 ± 5.9 vs. 0.45 ± 0.15 ng/mL). Similarly, TK1a in hematological malignancies was significantly higher than in healthy dogs (mean ± SD = 15.1 ± 31.3 vs. 0.96 ± 0.33 pmol/min/mL). The receiver-operating characteristic indicated that a combination of TK1p or TK1a with CRP gave higher sensitivity than either biomarker alone for the prognosis of hematological malignancies. Median pretreatment TK1p and TK1a levels were significantly higher than in dogs in remission and correlated with clinical outcome. Kaplan-Meier curve analysis showed that naive dogs with high TK1p, TK1a, and CRP had significantly shorter survival. This study present two new polyclonal antibodies used in an ELISA system to determine TK1p. The study also show that combining TK1p or TK1a with CRP gave higher sensitivity than either biomarker alone. Monitoring patients in the study while undergoing chemotherapy, suggests that the TK1 + CRP combination could be useful in a biomarker panel, possibly aiding the prognosis and therapy monitoring of hematological malignancies in dogs.

Clinical characteristics and outcome of invasive fungal sinusitis in children with hematological malignancies.

Invasive fungal sinusitis (IFS) is a rare disease that requires careful attention and prompts management due to its high mortality among pediatric patients with hematological malignancies. This is a retrospective analysis of pediatric patients with hematological malignancies treated at Children's Cancer Hospital Egypt 57 357 (CCHE) through the period from 2008 till 2016 with proven IFS. Thirty-four patients were diagnosed with IFS. Five (15%) patients had an invasive rhino-cerebral fungal disease. Mucorales were isolated in 50% (n = 17) patients, Aspergillus in 38% (n = 13) patients, and mixed fungal in 12% (n = 4) patients. Sinuses were the only localized site in (45%). Extra-nasal spread was reported in 20 patients; Sino-pulmonary in 35% (n = 12), sino-cerebral in 15% (n = 5), and sino-orbital in 5% (n = 2) patients. Combined antifungal therapy with surgical debridement was done in 59% of patients with a better outcome when compared to those who received only medical antifungal treatment (P = .01). The overall mortality rate at week 12 was 35% (n = 12), and IFS attributable mortality was 20% (n = 7). IFS with cerebral extension carried the highest mortality rate for both 12-week all-cause (P = .04) and fungal-attributable (P = .01) mortality. Pediatric patients with hematologic malignancies are susceptible to invasive fungal sinusitis (IFS). Surgical debridement, combined with antifungal therapy, improves outcomes among those patients. IFS patients with cerebral extension had a higher risk of mortality. LAY SUMMARY: We studied the characteristics of invasive fungal sinusitis in children with hematological malignancies. Mucormycosis was the most common cause. Surgical debridement, combined with anti-fungal therapy, improves outcomes. Patients with rhino-cerebral fungal disease had a higher risk of mortality.

Invasive mold infection of the gastrointestinal tract: A case series of 22 immunocompromised patients from a single academic center.

Invasive mold infection (IMI) of the gastrointestinal (GI) tract is a rare complication in immunocompromised patients that carries a high mortality rate. It is most often described in the setting of disseminated disease. Early diagnosis and treatment are critical in its management, but this is rarely obtained, leading to delayed therapy. To describe the clinical characteristics, treatment and outcomes of this infection, we reviewed all the cases of adult patients with histopathological findings from autopsy or surgical specimens that demonstrated fungal invasion into the GI tract at Stanford Hospital & Clinics from January 1997 to August 2020. Twenty-two patients that met criteria were identified and they were all immunocompromised, either due to their underlying medical conditions or the treatments that they received. The most common underlying disease was hematological malignancies (63.6%) and the most common symptoms were abdominal pain, GI bleeding and diarrhea. A majority of patients (72.7%) had disseminated invasive mold infection, while the rest had isolated GI tract involvement. In 2/3 of our cases, the fungal genus or species was confirmed based on culture or PCR results. Given the very high mortality associated with GI mold infection, this diagnosis should be considered when evaluating immunocompromised patients with concerning GI signs and symptoms. A timely recognition of the infection, prompt initiation of appropriate antifungal therapy as well as surgical intervention if feasible, are key to improve survival from this devastating infection. LAY SUMMARY: Patients with a weakened immune system can suffer from mold infections in the bowel, which are difficult to diagnose and have very high death rate. We examined such cases in our institution in order to learn about their clinical and microbiological features. This study can further improve our understanding of these infections in order to improve patient outcome.

Are severe adverse events commonly observed in dogs during cancer chemotherapy? A retrospective study on 155 dogs.

Overall prevalence of severe adverse events (sAE) has been poorly studied in veterinary medicine and peer-reviewed studies mostly focused on a single protocol, making it difficult to have a general overview. The aim of this retrospective study was to assess the frequency and risk factors of sAE secondary to various protocols of chemotherapy in dogs. Medical records of 155 dogs receiving chemotherapy between January 2013 and December 2018 were reviewed. Adverse events (AE) were graded according to Veterinary Comparative Oncology Group-common terminology criteria for AE (VCOG-CTCAE) grading system. Statistical analyses were performed to determine whether demographic, cancer type and chemotherapy protocol were associated with development of sAE and their consequences. AE were reported at least once in 124 (80%) dogs and sAE were observed in 50 (32.3%) dogs. Among them, 23 (14.8%) had gastro-intestinal and 31 (20.0%) had myelotoxic events. sAE led to hospitalisation in 37 (23.9%) dogs, to chemotherapy arrest in 12 (7.7%) dogs and to euthanasia or death in 9 (5.8%) dogs. Haematopoietic tumours were statistically associated with a higher frequency of sAE (p = .004), gastrointestinal sAE (p = .009) and hospitalisation (p = .004). A body weight over 10 kg was associated with less haematological sAE (p < .001). The use of a multi-agent protocol was highlighted as a risk factor for sAE (p = .038) and haematological sAE (p < .001). sAE following chemotherapy and leading to hospitalisation, chemo arrest or death were relatively common. A special attention during chemotherapy follow-up should be given to small dogs and those receiving multi-agent protocol or treated for haematopoietic tumours.

Genome-wide DNA methylation profile in feline haematological tumours: A preliminary study.

Although DNA methylation has been analysed in few studies for a limited number of loci in cats with diseases, genome-wide profile of DNA methylation has never been addressed. The hypothesis for this study is that next-generation sequencing with sequential digestion of genomic DNA with SmaI and XmaI enzymes could provide highly quantitative information on methylation levels in cats. Using blood from four healthy control cats and two disease cats as well as three feline lymphoma/leukemia cell lines, approximately 74-94 thousand CpG sites across the cat genome could be analysed. CpG sites in CpG island (CGI) were broadly either methylated or unmethylated in normal blood, while CpG sites in non-CpG islands (NCGI) are largely methylated. Lymphoma cell lines showed thousands of CpG sites with gain of methylation at normally unmethylated CGI sites and loss of methylation at normally methylated NCGI sites. Hypermethylated CpG sites located at promoter regions included genes annotated with 'developmental process' and 'anatomical structure morphogenesis' such as HOXD10. This highly quantitative method would be suitable for studies of DNA methylation changes not only in cancer but also in other common diseases in cats.

Multi-omics approach identifies germline regulatory variants associated with hematopoietic malignancies in retriever dog breeds.

Histiocytic sarcoma is an aggressive hematopoietic malignancy of mature tissue histiocytes with a poorly understood etiology in humans. A histologically and clinically similar counterpart affects flat-coated retrievers (FCRs) at unusually high frequency, with 20% developing the lethal disease. The similar clinical presentation combined with the closed population structure of dogs, leading to high genetic homogeneity, makes dogs an excellent model for genetic studies of cancer susceptibility. To determine the genetic risk factors underlying histiocytic sarcoma in FCRs, we conducted multiple genome-wide association studies (GWASs), identifying two loci that confer significant risk on canine chromosomes (CFA) 5 (Pwald = 4.83x10-9) and 19 (Pwald = 2.25x10-7). We subsequently undertook a multi-omics approach that has been largely unexplored in the canine model to interrogate these regions, generating whole genome, transcriptome, and chromatin immunoprecipitation sequencing. These data highlight the PI3K pathway gene PIK3R6 on CFA5, and proximal candidate regulatory variants that are strongly associated with histiocytic sarcoma and predicted to impact transcription factor binding. The CFA5 association colocalizes with susceptibility loci for two hematopoietic malignancies, hemangiosarcoma and B-cell lymphoma, in the closely related golden retriever breed, revealing the risk contribution this single locus makes to multiple hematological cancers. By comparison, the CFA19 locus is unique to the FCR and harbors risk alleles associated with upregulation of TNFAIP6, which itself affects cell migration and metastasis. Together, these loci explain ~35% of disease risk, an exceptionally high value that demonstrates the advantages of domestic dogs for complex trait mapping and genetic studies of cancer susceptibility.

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.

Ubiquitin-specific protease 7 as a potential therapeutic target in dogs with hematopoietic malignancies.

BACKGROUND: Ubiquitin-specific protease 7 (USP7) belongs to the group of deubiquitinating enzymes (DUBs), which remove ubiquitin which controls various cellular processes such as chromosome segregation, DNA repair, gene expression, protein localization, kinase activity, protein degradation, cell cycle progression, and apoptosis. It is critical for several important functions in the cell, and therefore dysregulation of USP7 can contribute to tumorigenesis. OBJECTIVES: Alterations in the USP7 protein have been identified in various malignancies of humans. Our aim was to examine whether USP7 could be a potential therapeutic target in hematopoietic cancers of dogs. METHODS: The expression level of USP7 in lymphocytes from healthy dogs and canine lymphoma cells was determined, and the effect of USP7 inhibition on the vital functions of canine cancer cells was examined. RESULTS: We showed that USP7 was overexpressed in lymphomas in dogs. The USP7 inhibitor P5091 has selective cytotoxic activity in canine lymphoma and leukemia cell lines. Our results indicate that inhibition of USP7 leads to a disruption of cell cycle progression, and triggers DNA damage and apoptosis. The observed proapoptotic effect of the USP7 inhibitor most likely is not dependent on the p53 pathway. CONCLUSIONS AND CLINICAL IMPORTANCE: Our results suggest that USP7 could be explored as a potential therapeutic target in dogs with lymphoma. The effectiveness of USP7 inhibition in malignant cells is predicted to be independent of their p53 status.

Multicenter flow cytometry proficiency testing of canine blood and lymph node samples.

BACKGROUND: Flow cytometry (FC) is used increasingly in veterinary medicine for further characterization of hematolymphoid cells. Guidelines for optimizing assay performance and interpretation of results are limited, and concordance of results across laboratories is unknown. OBJECTIVES: This study aimed to determine inter-investigator agreement on the interpretation of FC results from split samples analyzed in different laboratories using various protocols, cytometers, and software; and on the interpretation of archived FC standard (FCS) data files contributed by the different investigators. METHODS: This was a multicenter observational cross-sectional study. Anticoagulated blood or lymph node aspirate samples from nine client-owned dogs were aliquoted and shipped to participating laboratories. Samples were analyzed with individual laboratory-developed protocols. In addition, FCS files from a set of separate samples from 11 client-owned dogs were analyzed by participating investigators. A person not associated with the study tabulated the results and interpretations. Agreement of interpretations was assessed with Fleiss' kappa statistic. RESULTS: Prolonged transit times affected sample quality for some laboratories. Overall agreement among investigators regarding the FC sample interpretation was strong (κ = 0.86 ± 0.19, P < .001), and for specific categories, ranged from moderate to perfect. Agreement of the lymphoproliferation or other leukocyte sample category from the analysis of the FCS files was weak (κ = 0.58 ± 0.05, P < .001). CONCLUSIONS: Lymphoproliferations were readily identified by FC, but identification of the categories of hematolymphoid neoplasia in fresh samples or archived files was variable. There is a need for a more standardized approach to maximize the enormous potential of FC in veterinary medicine.

CAR T Cell Immunotherapy in Human and Veterinary Oncology: Changing the Odds Against Hematological Malignancies.

The advent of the genome editing era brings forth the promise of adoptive cell transfer using engineered chimeric antigen receptor (CAR) T cells for targeted cancer therapy. CAR T cell immunotherapy is probably one of the most encouraging developments for the treatment of hematological malignancies. In 2017, two CAR T cell therapies were approved by the US Food and Drug Administration: one for the treatment of pediatric acute lymphoblastic leukemia (ALL) and the other for adult patients with advanced lymphomas. However, despite significant progress in the area, CAR T cell therapy is still in its early days and faces significant challenges, including the complexity and costs associated with the technology. B cell lymphoma is the most common hematopoietic cancer in dogs, with an incidence approaching 0.1% and a total of 20-100 cases per 100,000 individuals. It is a widely accepted naturally occurring model for human non-Hodgkin's lymphoma. Current treatment is with combination chemotherapy protocols, which prolong life for less than a year in canines and are associated with severe dose-limiting side effects, such as gastrointestinal and bone marrow toxicity. To date, one canine study generated CAR T cells by transfection of mRNA for CAR domain expression. While this was shown to provide a transient anti-tumor activity, results were modest, indicating that stable, genomic integration of CAR modules is required in order to achieve lasting therapeutic benefit. This commentary summarizes the current state of knowledge on CAR T cell immunotherapy in human medicine and its potential applications in animal health, while discussing the potential of the canine model as a translational system for immuno-oncology research.

The cyclooxygenase-2/prostaglandin E2 pathway and its role in the pathogenesis of human and dog hematological malignancies.

The overexpression of cyclooxygenase-2 (COX-2) has been documented in many types of cancer occurring in humans and animals. Increasing evidences have shown that the overexpression of COX-2 and increased production of prostaglandin E2 (PGE2) correlate with poor prognosis in human solid tumours and hematological malignancies. Both, in vitro and in vivo studies have demonstrated that increased proliferation of cancer cells as well as an impairment of anti-tumour immunity are influenced by the overexpression of this enzyme. In leukemia and lymphoma, an increased activity of COX-2 and subsequent increase in prostaglandins (PGs) concentration allow cancer cells to evade immune response and contribute to metastases. Cancer stem cells (CSCs) in tumour microenvironment, suppression of innate and adaptive immunity depends on COX-2/PGE22 axis activity which increases in hematological malignancies. Cyclooxygenases inhibitors block the formation of PGs, consequently inhibiting angiogenesis, and in some malignancies they decrease cancer cells proliferation and tumour invasiveness. They also increase apoptosis of CSCs and cancer cells, decrease their drug resistance as well as enhance the host immune response. Therefore COX-2/PGE2 axis suppressors: selective COX-2 inhibitors or PG receptors antagonists have been considered as promising anticancer drugs. In comparative oncology dogs are increasingly used as a large animal model because they share the same environmental conditions with people and are exposed to the same environmental factors and also due to their relatively short life span. In dogs, spontaneously occurring non-Hodgkin lymphomas and leukemias have a large number of genetic and morphological features that are similar to those of humans' corresponding cancers. This, additionally makes the species a useful model for the study of new therapeutic strategies in human oncology. While the influence of COX-2 activity and PGE2 receptors have been evaluated extensively in human cancer, their role in veterinary oncology still needs to be elucidated.