A review of the current standing of microRNA expression in canine urothelial carcinoma.

Urothelial carcinoma (UC) is the most common urogenital cancer in dogs. With early diagnosis, the disease can be controlled, to reduce progression of disease, in most dogs with a good quality of life. MicroRNAs (miRNAs) have been identified as a potential diagnostic and prognostic tool due to their stability and presence in both bodily fluids and tissues. MiRNAs have been frequently researched in human medicine and human UC; however, few manuscripts regarding miRNAs in canine UC are available. A search was performed on both PubMed and Google Scholar evaluating original research manuscripts with experimentally validated results for the terms "canine" or "dog"; "urothelial carcinoma," "bladder cancer," "transitional cell carcinoma," "TCC," "MIBC," "IMBUC," or "BLCA"; and "miRNA" or "microRNA." We identified 3 peer-reviewed manuscripts evaluating miRNA expression in canine UC and compared the reported miRNA expression studies to human UC to identify experimentally validated targets of the dysregulated miRNA. In this review, we highlight the similarities and differences between what is reported in canine UC and human UC and discuss the literature gaps that call for further evaluation.

Canine urothelial carcinoma: a pilot study of microRNA detection in formalin-fixed, paraffin-embedded tissue samples and in normal urine.

We assessed the effects of fixation time in formalin and inclusion of surrounding tissue on microRNA (miRNA) cycle quantification (Cq) values in formalin-fixed, paraffin-embedded (FFPE) urothelial carcinoma (UC) tissue (n = 3), and the effect of conditions on miRNAs in urine from 1 healthy dog. MiRNAs were extracted using commercial kits and quantified using miRNA-specific fluorometry in normal bladder tissue scrolls, UC tissue cores, and bladder muscularis tissue cores from 4 FFPE bladder sections (3 UCs, 1 normal), plus 1 UC stored in formalin for 1, 8, 15, and 22 d before paraffin-embedding. Urine was collected from a healthy dog on 4 occasions; 1-mL aliquots were stored at 20, 4, -20, and -80°C for 4, 8, 24, and 48 h, and 1 and 2 wk. For both FFPE tissue and urine, we used reverse-transcription quantitative real-time PCR (RT-qPCR) to quantify miR-143, miR-152, miR-181a, miR-214, miR-1842, and RNU6B in each tissue or sample, using miR-39 as an exogenous control gene. The Cq values were compared with ANOVA and t-tests. The time of tissue-fixation in formalin did not alter miRNA Cq values; inclusion of the muscularis layer resulted in a statistically different miRNA Cq profile for miR-152, miR-181a, and RNU6B in bladder tissue. MiRNAs in acellular urine were stable for up to 2 wk regardless of the storage temperature. Our findings support using stored FFPE and urine samples for miRNA detection; we recommend measuring miRNA only in the tissue of interest in FFPE sections.

A review on microRNA detection and expression studies in dogs.

MicroRNAs (miRNAs) are small non-coding RNAs that function by post-transcriptional regulation of gene expression. Their stability and abundance in tissue and body fluids makes them promising potential tools for both the diagnosis and prognosis of diseases and attractive therapeutic targets in humans and dogs. Studies of miRNA expression in normal and disease processes in dogs are scarce compared to studies published on miRNA expression in human disease. In this literature review, we identified 461 peer-reviewed papers from database searches using the terms "canine," "dog," "miRNA," and "microRNA"; we screened 244 for inclusion criteria and then included a total of 148 original research peer-reviewed publications relating to specific miRNA expression in canine samples. We found an overlap of miRNA expression changes between the four groups evaluated (normal processes, non-infectious and non-inflammatory conditions, infectious and/or inflammatory conditions, and neoplasia) in 39 miRNAs, 83 miRNAs in three of the four groups, 110 miRNAs in two of the three groups, where 158 miRNAs have only been reported in one of the groups. Additionally, the mechanism of action of these overlapping miRNAs varies depending on the disease process, elucidating a need for characterization of the mechanism of action of each miRNA in each disease process being evaluated. Herein we also draw attention to the lack of standardization of miRNA evaluation, consistency within a single evaluation method, and the need for standardized methods for a direct comparison.

B-cell leukemia in an adult sheep.

B-cell leukemia is a rare form of hematologic neoplasia in sheep, especially in adult animals. We present a case report of a 5-year-old WhiteFace Sheep wether with suspected acute lymphoblastic leukemia. The patient, a second-generation relative of ewes experimentally inoculated with atypical scrapie, exhibited acute lethargy and loss of appetite. Laboratory investigation revealed marked leukocytosis, lymphocytosis, and abnormal serum chemistry panel results. Microscopic examination of blood and bone marrow smears exhibited a high percentage of large neoplastic cells with lymphoid characteristics. Histopathologic analysis of the spleen, liver, lungs, and other organs confirmed the presence of widespread tissue infiltration by neoplastic cells. Immunohistochemical labeling demonstrated strong intracytoplasmic labeling for CD20, consistent with B-cell neoplasia. Flow cytometric analysis confirmed the B-cell lineage of the neoplastic cells. Screening for bovine leukemia virus, which can experimentally cause leukemia in sheep, yielded a negative result. In this case, the diagnosis of B-cell leukemia was supported by a comprehensive panel of diagnostic evaluations, including cytology, histopathology, immunohistochemistry, and immunophenotyping. This case report highlights the significance of accurate diagnosis and classification of hematologic neoplasia in sheep, emphasizing the need for immunophenotyping to aid in the diagnosis of B-cell leukemia. It also emphasizes the importance of considering spontaneous leukemia as a differential diagnosis in sheep with lymphoid neoplasia, especially in the absence of circulating infectious diseases.

Hemophagocytic syndrome associated with large granular lymphoma in an adult dog.

Hemophagocytic syndrome (HPS) is a rare disorder characterized by dysregulation of the immune response resulting in uncontrolled activation of macrophages with exacerbated phagocytosis of host cells. In dogs, the criteria for diagnosis include the presence of pancytopenia or bicytopenia in the peripheral blood and >2% hemophagocytic macrophages in bone marrow aspirates. When HPS is associated with lymphoma, it is called lymphoma-associated hemophagocytic syndrome (LAHS). Here, we present a case of a 4 ½-year-old female spayed Old English Mastiff that presented with severe thrombocytopenia, mild anemia, mild to moderate leukopenia, and large granular lymphocytes (LGLs) in the peripheral blood. The patient had enlarged lymph nodes with many LGLs seen cytologically, leading to the interpretation of LGL lymphoma. Bone marrow displayed numerous LGLs that stained strongly for CD3 but did not show immunoreactivity to CD4 or CD8, and PCR for antigen receptor rearrangement analysis confirmed a clonal T-cell receptor gamma gene rearrangement. The presence of ~3.5% hemophagocytes present on the bone marrow evaluation raised concern for HPS and, more specifically, LAHS. HPS and LAHS are challenging to diagnose and require many criteria to be fulfilled before a definitive diagnosis can be made; the low number of cases in the literature makes this even more challenging in dogs. This case represents secondary LAHS due to LGL lymphoma in a dog.

The miRNome of canine invasive urothelial carcinoma.

Urothelial carcinoma (UC) comprises up to 2% of all naturally occurring neoplasia in dogs and can be challenging to diagnose. MicroRNAs (miRNAs) have been reported to be dysregulated in numerous diseases, including neoplasia. MiRNA expression has been evaluated in human UC, but there is limited information regarding the miRNA transcriptome of UC in dogs. Our study aimed to evaluate differential miRNA expression in bladder tissue collected from normal canine urothelium and canine invasive UC (iUC) to elucidate the dysregulated pathways in canine UC. Next-Generation RNA sequencing (RNA-Seq) was performed for dogs with UC (n = 29) and normal canine urothelium (n = 4). Raw RNA data were subjected to normalization, and pairwise comparison was performed using EdgeR with Benjamini-Hochberg FDR multiple testing correction (p < 0.05; >2-fold change) comparing tissue samples of normal urothelium to canine iUC samples. Principal component analysis and hierarchical cluster analysis were performed. MiRNA of FFPE tissue samples of separate iUC (n = 5) and normal urothelium (n = 5) were used to evaluate five miRNAs using RT-qPCR. Pathway analysis was performed utilizing miRWalk, STRING database, and Metascape utilizing KEGG pathways and GO terms databases. Twenty-eight miRNAs were differentially expressed (DE) by RNA-Seq. RT-qPCR confirmed that four miRNAs are significantly downregulated in UC compared to healthy urothelial samples (miR-105a, miR-143, miR-181a, and miR-214). Principal component analysis and hierarchical cluster analysis showed separation between miRNAs in iUC and the control group. The DE miRNAs are most often associated with gene silencing by miRNA, miRNAs in cancer, and miRNAs involved in DNA damage responses. Proteins involved include HRAS, KRAS, ARAF, RAF1, MAPK1, MAP2K1, MAPK3, FGFR3, EGFR, HBEGF, RASSF1, E2F2, E2F3, ERBB2, SRC, MMP1, and UP3KA. The differential expression of miRNAs in canine iUC compared to normal canine urothelial tissue indicates that these markers should be further evaluated for their potential role as diagnostic and therapeutic targets.

A case of hypercalcemia in a heifer presumably due to mammary carcinoma bovine hypercalcemia of malignancy.

Mammary carcinoma is rare in cattle with only a handful of cases found in the literature, and none have reported an associated hypercalcemia. An 8-year-old Holstein-Friesian heifer was presented to the Purdue University Veterinary Teaching Hospital's Large Animal Hospital with a 3-month history of lethargy. Laboratory abnormalities included ionized hypercalcemia and hypophosphatemia (2.28 mmol/L and 1.8 mg/dL, respectively). Physical examination revealed a mammary mass that was cytologically described as a suspected mammary carcinoma, which was later confirmed by histologic evaluation. On surgical removal of the mass, calcium initially decreased rapidly, and within a few days was within the RI, further supporting a diagnosis of hypercalcemia of malignancy in a heifer. However, attempts to confirm this using hormone profiles (parathyroid hormone [PTH], parathyroid hormone-related protein [PTHrp], and calcitriol) were inconclusive due to the lack of validated assays and RIs for cattle. Immunohistochemical staining for PTHrP showed scattered cytoplasmic staining among the neoplastic cells, suggesting PTHrP production by these cells.