Prognostic value of epigenetic markers for canine mast cell cancer.

Canine Mast cell tumors (MCTs) constitute approximately 21% of all canine skin tumors. Despite the use of comprehensive grading systems, biological aggressiveness is sometimes difficult to predict, therefore there is a need for better prognostic markers. Progression in various cancers involves DNA hypermethylation, hypomethylation and epigenetic enzyme dysregulation. Therefore, global levels of 5-methylcytosine, 5-hydroxymethylcytosine and associated enzymes DNMT1, and IDH1 expression may predict MCT aggressiveness. A tissue microarray (TMA) with cores from 244 different tumor samples from 189 dogs was immunolabelled and used to quantify the global DNA methylation and hydroxymethylation levels as well as the levels of the enzymes involved in DNA methylation and their relationship with canine MCT outcome. From the immunolabelled TMA, H-scores were generated using QuPath (v0.1.2) and analyzed with associated patient data. High 5MC and DNMT1, and low IDH1 levels were associated with poorer outcome when looking at all canine MCT cases. High 5MC levels showed significance for shorter disease-free interval (DFI) in subcutaneous cases and high 5MC levels showed poorer DFI and overall survival (OS) in cases with Kiupel's grading system high grade. Cases with grade II in Patnaik's grading system showed better DFI with low levels of DNMT1 and better OS with low levels of 5MC and 5HMC. High levels of DNMT1 staining were also associated with shorter DFI for dermal MCTs. For cases that received adjuvant therapy in addition to surgery, all parameters except IDH1 were significantly associated with OS. Therefore, there is potential for DNA methylation status and levels of enzymes associated with DNA methylation pathways to better predict outcome in canine MCT, and to possibly influence treatment decisions.

Whole genome sequencing analysis of high confidence variants of B-cell lymphoma in Canis familiaris.

Lymphoma (lymphosarcoma) is the second most frequent cancer in dogs and is clinically comparable to human non-Hodgkin lymphoma. Factors affecting canine lymphoma progression are unknown and complex, but there is evidence that genetic mutations play an important role. We employed Next Gen DNA sequencing of six dogs with multicentric B-cell lymphoma undergoing CHOP chemotherapy to identify genetic variations potentially impacting response. Paired samples from non-neoplastic tissue (blood mononuclear cells) and lymphoma were collected at the time of diagnosis. Cases with progression free survival above the median of 231 days were grouped as 'good' responders and cases below the median were categorized as 'poor' responders. The average number of variants found was 17,138 per case. The variants were filtered to examine those with predicted moderate or high impacts. Many of the genes with variants had human orthologs with links to cancer, but the majority of variants were not previously reported in canine or human lymphoma. Seven genes had variants found in the cancers of at least two 'poor' responders but in no 'good' responders: ATRNL1, BAIAP2L2, ZNF384, ST6GALNAC5, ENSCAFG00000030179 (human ortholog: riboflavin kinase RFK), ENSCAFG00000029320, and ENSCAFG00000007370 (human ortholog: immunoglobin IGKV4-1). Two genes had variants found in the cancers of at least two 'good' responders but in no 'poor' responders: COX18 and ENSCAFG00000030512. ENSCAFG00000030512 has no reported orthologue in any other species. The role of these mutations in the progression of canine lymphoma requires further functional analyses and larger scale study.

Liver morphometrics and metabolic blood profile across divergent phenotypes for feed efficiency in the bovine.

BACKGROUND: Feed costs are a major expense in the production of beef cattle. Individual variation in the efficiency of feed utilization may be evident through feed efficiency-related phenotypes such as those related to major energetic sinks. Our objectives were to assess the relationships between feed efficiency with liver morphometry and metabolic blood profile in feedlot beef cattle. METHODS: Two populations (A = 112 and B = 45) of steers were tested for feed efficiency. Blood from the 12 most (efficient) and 12 least feed inefficient (inefficient) steers from population A was sampled hourly over the circadian period. Blood plasma samples were submitted for analysis on albumin, aspartate aminotransferase, γ-glutamyl transpeptidase urea, cholesterol, creatinine, alkaline phosphatase, creatine kinase, lipase, carbon dioxide, ß-hydroxybutyrate, acetate and bile acids. Liver tissue was also harvested from 24 steers that were blood sampled from population A and the 10 steers with divergent feed efficiency in each tail of population B was sampled for microscopy at slaughter. Photomicroscopy images were taken using the portal triad and central vein as landmarks. Histological quantifications included cross-sectional hepatocyte perimeter and area, hepatocyte nuclear area and nuclei area as proportion of the hepatocyte area. The least square means comparison between efficient and inefficient steers for productive performance and liver morphometry and for blood analytes data were analyzed using general linear model and mixed model procedures of SAS, respectively. RESULTS: No differences were observed for liver weight; however, efficient steers had larger hepatocyte (i.e. hepatocyte area at the porta triad 323.31 vs. 286.37 µm2) and nuclei dimensions at portal triad and central vein regions, compared with inefficient steers. The metabolic profile indicated efficient steers had lower albumin (36.18 vs. 37.65 g/l) and cholesterol (2.62 vs. 3.05 mmol/l) and higher creatinine (118.59 vs. 110.50 mmol/l) and carbon dioxide (24.36 vs. 23.65 mmol/l) than inefficient steers. CONCLUSIONS: Improved feed efficiency is associated with increased metabolism by the liver (enlarged hepatocytes and no difference on organ size), muscle (higher creatinine) and whole body (higher carbon dioxide); additionally, efficient steers had reduced bloodstream pools of albumin and cholesterol. These metabolic discrepancies between feed efficient and inefficient cattle may be determinants of productive performance.