Enteral metallic stenting by balloon enteroscopy for obstruction of surgically reconstructed intestine.

We present three cases of self-expandable metallic stent (SEMS) placement using a balloon enteroscope (BE) and its overtube (OT) for malignant obstruction of surgically reconstructed intestine. A BE is effective for the insertion of an endoscope into the deep bowel. However, SEMS placement is impossible through the working channel, because the working channel of BE is too small and too long for the stent device. Therefore, we used a technique in which the BE is inserted as far as the stenotic area; thereafter, the BE is removed, leaving only the OT, and then the stent is placed by inserting the stent device through the OT. In the present three cases, a modification of this technique resulted in the successful placement of the SEMS for obstruction of surgically reconstructed intestine, and the procedures were performed without serious complications. We consider that the present procedure is extremely effective as a palliative treatment for distal bowel stenosis, such as in the surgically reconstructed intestine.

Urgent computed tomography for determining the optimal timing of colonoscopy in patients with acute lower gastrointestinal bleeding.

OBJECTIVE: We evaluated the diagnostic performance of computed tomography (CT) as an initial radiologic test for assessing the optimal timing of colonoscopy in patients with acute lower gastrointestinal bleeding (LGIB) and investigated the effectiveness of contrast-enhanced (CE) CT for detecting colonic diverticular bleeding. METHODS: This was a retrospective study of 1,604 consecutive patients who visited or were referred to St. Marianna University Hospital due to acute LGIB and underwent colonoscopy within three months after presentation between September 2004 and December 2012. The clinicopathological data of the subjects were obtained from their medical records. RESULTS: Among the 1,604 patients presenting with LGIB, 879 (55%) underwent a CT scan. Elective colonoscopy was considered in cases in which typical colonic wall thickening was observed on CT, suggesting colonic inflammation or malignancy (239 patients; 27%). The diagnoses in the elective cases included ischemic colitis (38%), infectious colitis (8%), inflammatory bowel disease (8%) and malignancy (5%). Urgent colonoscopy was performed after the CT examination in 640 cases (73%). The most common presumptive CT diagnosis was diverticulum (402/640; 63%). Of the 638 patients who underwent CE-CT, diverticula were observed in 346 cases, including 104 cases of extravasation indicating ongoing diverticular bleeding. Among these 104 patients, the site of bleeding was identified in 71 subjects (68%) during colonoscopy. The rate of detection of the bleeding source on colonoscopy was significantly higher in the patients with extravasation on CE-CT than in those without extravasation on CE-CT (68% vs. 20%, respectively; p<0.001). CONCLUSION: Urgent CT is useful for determining the optimal timing of colonoscopy in cases of acute LGIB. CE-CT may be used to depict the presence and location of active hemorrhage and provides useful information for subsequent colonoscopy, especially in patients with diverticular bleeding.

Endoscopic retrograde cholangiography using an anterior oblique-viewing endoscope in patients with altered gastrointestinal anatomy.

BACKGROUND: Endoscopic retrograde cholangiopancreatography (ERCP) is technically more challenging in patients who have undergone gastrointestinal (GI) reconstruction. AIMS: The aim of this study was to evaluate the utility of the anterior oblique-viewing endoscope (AOE) for ERCP in patients with a retained major duodenal papilla after GI reconstruction. METHODS: This was a retrospective study involving 40 patients (50 procedures) with a retained papilla after GI reconstruction who underwent ERCP using AOE. Reconstruction consisted of Billroth II gastrectomy (BII) in 25 patients (30 procedures) and Roux-en-Y anastomosis (RY) in 15 patients (20 procedures). In RY cases, the long single-balloon enteroscope (LSBE) was exchanged with AOE after reaching the papilla. RESULTS: The overall rate of reaching the papilla using AOE was 90.0 % (45/50) [BII; 86.7 % (26/30), RY; 95.0 % (19/20)]. The overall rate of biliary cannulation was 97.8 % (44/45) [BII; 100 % (26/26), RY; 94.7 % (18/19)], and the rate of biliary cannulation for intact papilla was 96.6 % (28/29) [BII; 100 % (14/14), RY; 93.3 % (14/15)]. Treatment success rate in cases of successful biliary cannulation was 97.7 % (43/44) [BII; 100 % (26/26), RY; 94.4 % (17/18)]. The rate of adverse events was 6.0 % (3/50) [BII; 3.3 % (1/30), RY; 10.0 % (2/20)], with mild pancreatitis occurring in 3 cases. CONCLUSIONS: High biliary cannulation and treatment rates can be achieved during ERCP using AOE in altered GI anatomy cases with a retained papilla, as long as the papilla can be reached. In RY cases, exchanging AOE with LSBE is useful after reaching the papilla.

An updated review of gastric cancer in the next-generation sequencing era: insights from bench to bedside and vice versa.

Gastric cancer (GC) is one of the most common malignancies and remains the second leading cause of cancer-related death worldwide. There is an increasing understanding of the roles that genetic and epigenetic alterations play in GCs. Recent studies using next-generation sequencing (NGS) have revealed a number of potential cancer-driving genes in GC. Whole-exome sequencing of GC has identified recurrent somatic mutations in the chromatin remodeling gene ARID1A and alterations in the cell adhesion gene FAT4, a member of the cadherin gene family. Mutations in chromatin remodeling genes (ARID1A, MLL3 and MLL) have been found in 47% of GCs. Whole-genome sequencing and whole-transcriptome sequencing analyses have also discovered novel alterations in GC. Recent studies of cancer epigenetics have revealed widespread alterations in genes involved in the epigenetic machinery, such as DNA methylation, histone modifications, nucleosome positioning, noncoding RNAs and microRNAs. Recent advances in molecular research on GC have resulted in the introduction of new diagnostic and therapeutic strategies into clinical settings. The anti-human epidermal growth receptor 2 (HER2) antibody trastuzumab has led to an era of personalized therapy in GC. In addition, ramucirumab, a monoclonal antibody targeting vascular endothelial growth factor receptor (VEGFR)-2, is the first biological treatment that showed survival benefits as a single-agent therapy in patients with advanced GC who progressed after first-line chemotherapy. Using NGS to systematically identify gene alterations in GC is a promising approach with remarkable potential for investigating the pathogenesis of GC and identifying novel therapeutic targets, as well as useful biomarkers. In this review, we will summarize the recent advances in the understanding of the molecular pathogenesis of GC, focusing on the potential use of these genetic and epigenetic alterations as diagnostic biomarkers and novel therapeutic targets.

Development of a novel output value for quantitative assessment in methylated DNA immunoprecipitation-CpG island microarray analysis.

In DNA methylation microarray analysis, quantitative assessment of intermediate methylation levels in samples with various global methylation levels is still difficult. Here, specifically for methylated DNA immunoprecipitation-CpG island (CGI) microarray analysis, we developed a new output value. The signal log ratio reflected the global methylation levels, but had only moderate linear correlation (r = 0.72) with the fraction of DNA molecules immunoprecipitated. By multiplying the signal log ratio using a coefficient obtained from the probability value that took account of signals in neighbouring probes, its linearity was markedly improved (r = 0.94). The new output value, Me value, reflected the global methylation level, had a strong correlation also with the fraction of methylated CpG sites obtained by bisulphite sequencing (r = 0.88), and had an accuracy of 71.8 and 83.8% in detecting completely methylated and unmethylated CGIs. Analysis of gastric cancer cell lines using the Me value showed that methylation of CGIs in promoters and gene bodies was associated with low and high, respectively, gene expression. The degree of demethylation of promoter CGIs after 5-aza-2'-deoxycytidine treatment had no association with that of induction of gene expression. The Me value was considered to be useful for analysis of intermediate methylation levels of CGIs.

Adenomatous polyposis coli 1A is likely to be methylated as a passenger in human gastric carcinogenesis.

Many promoter CpG islands (CGIs) are methylated as a consequence of or in association with carcinogenesis (passenger), in addition to being a cause of carcinogenesis (driver). In gastric cancers, promoter 1A of the adenomatous polyposis coli (APC) gene is frequently methylated, and is often discussed as a driver. However, the actual role of 1A methylation is unclear because the same APC protein is coded by two transcripts from two promoters, 1A and 1B, and their relative expression levels in gastric mucosae have not been quantified. To clarify this issue, we first identified detailed transcription start sites of 1A and 1B transcripts. We then confirmed that, among nine gastric cancer cell lines, 1A methylation, if present, could repress 1A transcription while 1B was expressed and not methylated. In primary samples, 1B expression was 15-fold higher than 1A expression in gastric mucosae of healthy volunteers, and was decreased markedly in non-cancerous gastric mucosae of cancer patients. Quantitative methylation analysis showed that promoter 1A was methylated at similar levels (20-40%) in healthy individuals and non-cancerous gastric mucosae of cancer patients, and promoter 1B was never methylated in any samples, including gastric cancers. These findings strongly indicated that methylation of APC promoter 1A is a passenger, and suggested that marked down-regulation of 1B expression could be related to formation of a field predisposed to gastric cancers.

Methylation silencing of transforming growth factor-beta receptor type II in rat prostate cancers.

To identify methylation-silenced genes in prostate cancers, a microarray analysis for genes up-regulated by treatment with a demethylating agent, 5-aza-2'-deoxycytidine, was performed using three rat prostate cancer cell lines. Eight genes (Aebp1, Dysf, Gas6, LOC361288, Nnat, Ocm, RGD1308119, and Tgfbr2) were re-expressed at 16-fold or more, and their promoter CpG islands were shown to be densely methylated in the cancer cell lines. From the eight genes, Tgfbr2, a key mediator of transforming growth factor-beta (TGF-beta) signaling that has been strongly implicated in human and rat prostate carcinogenesis, was selected, and its silencing in primary samples was analyzed further. Tgfbr2 was methylated and markedly down-regulated in three of seven 3,2'-dimethyl-4-aminobiphenyl-induced invasive adenocarcinomas in the dorsolateral lobe of the rat prostate. In humans, marked down-regulation of TGFBR2 protein was observed in 12 of 20 high-grade prostatic intraepithelial neoplasia and 36 of 60 prostate cancers. DNA methylation of the human TGFBR2 promoter CpG islands repressed transcription, if present, but neither methylation nor mutation were detected in 27 human prostate cancers analyzed. Methylation silencing of rat Tgfbr2 was associated with histone H3 lysine 9 trimethylation, whereas decreased expression of human TGFBR2 was mainly due to decreased transcription activity, sometimes in concert with histone deacetylation and H3 lysine 27 trimethylation. The identification of methylation silencing of Tgfbr2 in rat prostate cancers, in accordance with TGFBR2 down-regulation in human prostate cancers, will enable us to analyze how aberrant methylation is induced in vivo and identify factors that promote and suppress the induction of aberrant methylation.