Cytomorphological description and intra-observer agreement in whole slide imaging for canine lymphoma.

Whole slide imaging (WSI) uses robotic microscopes for computerising entire slides into digital images. The aim of this study was to assess the agreement between WSI and optical microscopy for evaluating canine lymphoma cytological samples. Forty-four slides were computerised using a WSI scanner and the digital and glass slides were examined by three observers with different levels of expertise. Morphology and grade of lymphoma were scored on the basis of the updated Kiel classification and intra-observer agreement was assessed. The accuracy of determining the grade of lymphoma with digital and glass slides based on the results of flow cytometry (FC) was established. The overall intra-observer agreement for cytomorphological features was fair to moderate (κ=0.34-0.52) for the three observers and moderate (κ=0.44-0.53) for the evaluation of grade of malignancy. The diagnostic agreement between FC and digital slides was slight (κ=0.16) for the inexperienced observer, fair (κ=0.32) for the mildly experienced observer and moderate (κ=0.50) for the very experienced observer. The diagnostic agreement between FC and glass slides was fair (κ=0.37) for the inexperienced observer, substantial (κ=0.63) for the mildly experienced observer and moderate (κ=0.50) for the very experienced observer. These findings underline the importance of observer experience in determining the grade of malignancy, especially if digital slides are used. The study also identifies some technical limitations of the WSI scanner used in this study, mainly linked to image quality, which might affect the morphological evaluation of neoplastic cells.

European Veterinary Renal Pathology Service: A Survey Over a 7-Year Period (2008-2015).

BACKGROUND: The European Veterinary Renal Pathology Service (EVRPS) is the first Web-based registry for canine renal biopsy specimens in Europe. HYPOTHESIS/OBJECTIVES: The aim was to verify whether differences exist between the clinical and laboratory presentation of dogs with nephropathy according to renal pathological findings, as defined by light and electron microscopy of renal biopsy specimens submitted to EVRPS. ANIMALS: Renal biopsy specimens of dogs were collected from the archive of the service (n = 254). Cases were included if both light and electron microscopy were available (n = 162). METHODS: Renal biopsy specimens were classified based on the morphological diagnoses. Thereafter, they were grouped into 3 disease categories, including immune-complex-mediated glomerulonephritis (ICGN), non-immune-complex-mediated GN (non-ICGN), and renal lesions not otherwise specified (RL-NOS). Differences among morphological diagnoses and among disease categories were investigated for clinical and laboratory variables. RESULTS: Serum albumin concentration was lower in dogs with ICGN than in those with non-ICGN (P = 0.006) or RL-NOS (P = 0.000), and the urine protein-to-creatinine ratio (UPC) was significantly higher in ICGN than in the other 2 disease categories. Regarding morphological diagnoses, albumin was significantly lower in amyloidosis (AMY) and membranous (MGN), membranoproliferative (MPGN) or mixed glomerulonephritis (MixGN) than in minimal change disease, primary (FSGS I) or secondary (FSGS II) focal and segmental glomerulosclerosis and juvenile nephropathies (JN). The UPC was higher in MPGN than in FSGS I and FSGS II. CONCLUSIONS AND CLINICAL IMPORTANCE: Dogs with ICGN, in particular MPGN, had higher protein loss than those with non-ICGN or RL-NOS, leading to more severe hypoalbuminemia. Clinical and laboratory differentiation among dogs with the different morphological diagnoses and among dogs with different disease categories was difficult due to overlapping results.

Posttransplant Lymphoproliferative Disorders in Neuronal Xenotransplanted Macaques.

Posttransplant lymphoproliferative disorders (PTLDs) are a heterogeneous group of lymphoid proliferations that occur in the setting of depressed T-cell function due to immunosuppressive therapy used following solid organ transplantation, hematopoietic stem cell transplantation, and also xenotransplantation. In the present study, 28 immunosuppressed parkinsonian Macaca fascicularis were intracerebrally injected with wild-type or CTLA4-Ig transgenic porcine xenografts to identify a suitable strategy to enable long-term cell survival, maturation, and differentiation. Nine of 28 (32%) immunosuppressed primates developed masses compatible with PTLD, located mainly in the gastrointestinal tract and/or nasal cavity. The masses were classified as monomorphic PTLD according to the World Health Organization classification. Immunohistochemistry and polymerase chain reaction (PCR) analyses revealed that the PTLDs were associated with macaca lymphocryptovirus as confirmed by double-labeling immunohistochemistry for CD20 and Epstein-Barr nuclear antigen 2 (EBNA-2), where the viral protein was located within the CD20+ neoplastic B cells. In sera from 3 distinct phases of the experimental life of the primates, testing by quantitative PCR revealed a progression of the viral load that paralleled the PTLD progression and no evidence of zoonotic transmission of porcine lymphotropic herpesvirus through xenoneuronal grafts. These data suggest that monitoring the variation of macaca lymphocryptovirus DNA in primates could be used as a possible early diagnostic tool for PTLD progression, allowing preemptive treatment such as immunosuppression therapy reduction.

A preliminary investigation of the role of the transcription co-activators YAP/TAZ of the Hippo signalling pathway in canine and feline mammary tumours.

Breast cancer is the most common cancer in women worldwide. Cancer metastases are responsible for the high mortality rate. A small but distinct subset of cells, cancer stem cells (CSCs), have the capacity to self-renew, initiate tumour formation, and develop metastases. The CSC content in human breast cancer correlates with the Hippo tumour suppressor signalling pathway. Specifically, the activity of YAP/TAZ, transcription co-activators of the Hippo pathway, sustains the self-renewal and tumour-initiation capacities of CSCs. Little is known about YAP/TAZ in canine and feline mammary tumours, which are very common tumours. The preliminary aim of the study was to investigate the expression of YAP/TAZ in canine and feline mammary tumours by Western blot and immunohistochemistry. Increased cytoplasmic and nuclear expression of YAP/TAZ was observed in all carcinomas compared to normal tissues, indicating neoplastic deregulation of the Hippo pathway. Nuclear expression significantly increased in grade III (high grade carcinomas) compared to grade I (low grade carcinomas) tumours, suggesting that YAP/TAZ play a role in the increased aggressiveness of these tumours. Moreover, different scoring systems for immunohistochemical analyses were compared and the H index and the Allred scores were the most significant. In conclusion, YAP/TAZ are expressed in aggressive canine and feline mammary tumours as reported in some human cancers. Further studies might better elucidate the role of the Hippo pathway in prognosis and as a target for new therapies. In addition, tumours in dogs and cats may be a useful model to study this pathway.

Immunohistochemical expression of E-cadherin and ß-catenin in feline mammary tumours.

E-cadherin and ß-catenin have been studied in carcinogenesis and tumour progression and reduced membrane expression of these molecules in canine mammary tumours has been associated with a poor prognosis. The present study investigated immunohistochemically the expression of E-cadherin and ß-catenin in 53 mammary tumours and 48 hyperplastic or dysplastic lesions from 57 queens. E-cadherin and ß-catenin expression was membranous in all samples and there was a significant decrease in expression in malignant tumours and metastases. Cytoplasmic expression of both markers was inversely correlated to the membrane localization. ß-catenin nuclear labelling was detected in one lymph node metastasis (60% positive cells) and in the basal/myoepithelial cells of 6/7 ductal tumours. No correlation with survival was found for either marker. These results confirm the role of these proteins in maintaining tissue architecture and in inhibiting cell invasiveness and potentially indicate the oncogenic potential of the Wnt/ß-catenin transduction pathway in feline mammary tumours. In addition, specific independent expression of ß-catenin in the nuclei of basal/myoepithelial cells might suggest that this molecule is involved in regulation of the mammary stem/pluripotent cell component. Further studies should include more cases of benign mammary neoplasia and further investigate ß-catenin nuclear expression in ductal tumours.

Severe renal failure in a dog resembling human focal segmental glomerulosclerosis.

A case of renal disease in a dog resembling human focal segmental glomerulosclerosis is presented. A kidney biopsy from this animal showed focal glomerular sclerosis, with variable distribution, affecting the perihilar and peripheral segments of the glomerular tuft. Non-sclerotic glomeruli were markedly enlarged. Interstitial fibrosis in association with tubular atrophy affected approximately 20% of the area of the biopsy. Immunofluorescence labelling showed immunoglobulin M deposits entrapped in segmental sclerotic areas and ultrastructural examination revealed segmental sclerosis and obliteration of capillaries, vacuolation of podocytes and diffuse effacement of foot processes. The dog was humanely destroyed 1 month later. At necropsy examination there was severe end-stage kidney disease with interstitial fibrosis involving more than 60% of the renal tissue. The clinical course and the microscopical, immunofluorescence and ultrastructural findings in this case have similarity to focal segmental glomerulosclerosis in man.