The landscape of PBMC methylome in canine mammary tumors reveals the epigenetic regulation of immune marker genes and its potential application in predicting tumor malignancy.

BACKGROUND: Genome-wide dysregulation of CpG methylation accompanies tumor progression and characteristic states of cancer cells, prompting a rationale for biomarker development. Understanding how the archetypic epigenetic modification determines systemic contributions of immune cell types is the key to further clinical benefits. RESULTS: In this study, we characterized the differential DNA methylome landscapes of peripheral blood mononuclear cells (PBMCs) from 76 canines using methylated CpG-binding domain sequencing (MBD-seq). Through gene set enrichment analysis, we discovered that genes involved in the growth and differentiation of T- and B-cells are highly methylated in tumor PBMCs. We also revealed the increased methylation at single CpG resolution and reversed expression in representative marker genes regulating immune cell proliferation (BACH2, SH2D1A, TXK, UHRF1). Furthermore, we utilized the PBMC methylome to effectively differentiate between benign and malignant tumors and the presence of mammary gland tumors through a machine-learning approach. CONCLUSIONS: This research contributes to a better knowledge of the comprehensive epigenetic regulation of circulating immune cells responding to tumors and suggests a new framework for identifying benign and malignant cancers using genome-wide methylome.

Alternative methylation of intron motifs is associated with cancer-related gene expression in both canine mammary tumor and human breast cancer.

BACKGROUND: Canine mammary tumor (CMT) has long been considered as a good animal model for human breast cancer (HBC) due to their pathological and biological similarities. However, only a few aspects of the epigenome have been explored in both HBC and CMT. Moreover, DNA methylation studies have mainly been limited to the promoter regions of genes. RESULTS: Genome-wide methylation analysis was performed in CMT and adjacent normal tissues and focused on the intron regions as potential targets for epigenetic regulation. As expected, many tumor suppressors and oncogenes were identified. Of note, most cancer-associated biological processes were enriched in differentially methylated genes (DMGs) that included intron DMRs (differentially methylated regions). Interestingly, two PAX motifs, PAX5 (tumor suppressive) and PAX6 (oncogenic), were frequently found in hyper- and hypomethylated intron DMRs, respectively. Hypermethylation at the PAX5 motifs in the intron regions of CDH5 and LRIG1 genes were found to be anti-correlated with gene expression, while CDH2 and ADAM19 genes harboring hypomethylated PAX6 motifs in their intron region were upregulated. These results were validated from the specimens originally MBD-sequenced as well as additional clinical samples. We also comparatively investigated the intron methylation and downstream gene expression of these genes using human breast invasive carcinoma (BRCA) datasets in TCGA (The Cancer Genome Atlas) public database. Regional alteration of methylation was conserved in the corresponding intron regions and, consequently, gene expression was also altered in HBC. CONCLUSIONS: This study provides good evidence for the conservation of epigenetic regulation in CMT and HBC, and suggests that intronic methylation can be an important factor in better understanding gene regulation in both CMT and HBC.

A randomized trial to determine the diagnostic accuracy of conventional vs. jumbo forceps biopsy of gastric epithelial neoplasias before endoscopic submucosal dissection; open-label study.

BACKGROUND AND AIMS: Larger biopsy specimens or increasing the number of biopsies may improve the diagnostic accuracy of gastric epithelial neoplasia (GEN). The aims of this study was to compare the diagnostic accuracies between conventional and jumbo forceps biopsy of GEN before endoscopic submucosal dissection (ESD) and to confirm that increasing the number of biopsies is useful for the diagnosis of GEN. RESULTS: The concordance rate between EFB and ESD specimens was not significantly different between the two groups [83.1 % (54/65) in JG vs. 79.1 % (53/67) in CG]. On multivariate analyses, two or four EFBs significantly increased the cumulating concordance rate [coefficients; twice: 5.1 (P = 0.01), four times: 5.9 (P = 0.02)]. But, the concordance rate was decreased in high grade dysplasia (coefficient -40.32, P = 0.006). PATIENTS AND METHODS: One hundred and sixty GENs from 148 patients were randomized into two groups and finally 67 GENs in 61 patients and 65 GENs in 63 patients were allocated to the conventional group (CG) or jumbo group (JG), respectively. Four endoscopic forceps biopsy (EFB) specimens were obtained from each lesion with conventional (6.8 mm) forceps or jumbo (8 mm) forceps. The histological concordance rate between 4 EFB specimens and ESD specimens was investigated in the two groups. CONCLUSIONS: Before ESD, the diagnostic accuracy of GENs was significantly increased not by the use of jumbo forceps biopsy but by increasing the number of biopsies.

Second-look endoscopy is not associated with better clinical outcomes after gastric endoscopic submucosal dissection: a prospective, randomized, clinical trial analyzed on an as-treated basis.

BACKGROUND: The efficacy of routine second-look endoscopy (SLE) to detect or prevent bleeding after gastric endoscopic submucosal dissection (ESD) has not yet been validated. OBJECTIVE: The aim of this study was to determine whether SLE affects clinical outcomes including bleeding and morbidity after gastric ESD. DESIGN: A prospective, randomized, controlled study with consecutive data analyzed on an as-treated basis. SETTING: A single, tertiary-care referral center. PATIENTS: A total of 182 patients. INTERVENTION: Gastric ESD and SLE. MAIN OUTCOME MEASUREMENTS: Incidence of and risk factors related to bleeding after ESD and outcomes by univariate or multivariate analysis. RESULTS: Among 182 patients enrolled, 74 and 81 patients were assigned to the SLE and no-SLE groups, respectively. Two groups were observed closely for 4 weeks. Bleeding occurred after ESD in 21 patients (13.5%). Hemoglobin loss (≥2.0 g/dL) was observed in 20 patients, and melena developed in 1 patient after ESD. However, only 1 patient needed a transfusion. Twelve patients (16.2%) in the SLE group and 9 in the no-SLE group (11.1%) experienced bleeding after ESD. The frequency of bleeding after ESD was not significantly different between the 2 groups (P = .66). There were no risk factors related to bleeding after ESD. LIMITATIONS: Single-center analysis. CONCLUSION: SLE is not routinely necessary because it does not affect clinical outcomes, including bleeding and morbidity after ESD. ( CLINICAL TRIAL REGISTRATION NUMBER: KCT0000146.).