The LECS procedure for dissection of gastric submucosal tumors such as GIST may be performed safely with reasonable operation times, less bleeding, and adequate cut lines. In addition, the success of the procedure does not depend on the tumor location such as the vicinity of the esophagogastric junction or pyloric ring.

Claudins (Cldn) are essential membrane proteins of tight junctions (TJs), which form the paracellular permselective barrier. They are produced by a multi-gene family of 24 reported members in mouse and human. Based on a comprehensive search combined with phylogenetic analyses, we identified three novel claudins (claudin-25, -26, and -27). Quantitative RT-PCR revealed that the three novel claudins were expressed in a tissue- and/or developmental stage-dependent manner. Claudins-25 and -26, but not claudin-27, were immunofluorescently localized to TJs when exogenously expressed in cultured MDCK and Eph epithelial cell lines. These findings expand the claudin family to include at least 27 members.

Background and Aim:To verify the current status in Japan on endoscopic diagnosis of superficial non-ampullary duodenal epithelial tumors (SNADET) by a multicenter case series through a questionnaire survey.Methods: Nine endoscopists and a surgeon responded to a questionnaire on endoscopic diagnosis of SNADET. The subjects of this survey were histologically confirmed SNADET that were endoscopically or surgically resected from 2007 to 2012. This survey collected data of 364 patients with 396 SNADET.Results: Of the 396 SNADET, 121 were histologically diagnosed as low-grade dysplasia (LGD), 112 as high-grade dysplasia (HGD), and 163 as superficial adenocarcinoma (SAC) including 153 mucosal carcinomas and 10 submucosal carcinomas. Total number of SNADET increased from 125 in the first half to 271 in the second half of the survey period. Compared to LGD, a significantly greater number of HGD or SAC was found in the tumors having a diameter >5 mm as well as solitary or predominantly red color. Preoperative endoscopic diagnosis indicated significantly higher sensitivity and accuracy and significantly lower specificity for HGD or SAC of final histology than preoperative biopsy. Ten submucosal carcinomas had 0-I or 0-IIa+IIc macroscopic-type tumors with red color.Conclusions: This multicenter case series study suggested that the number of resected SNADET is dramatically increasing in Japan. Tumor diameter >5 mm and red color seemed to be signs for tumors of HGD or SAC. Preoperative endoscopy may provide a more reliable diagnosis of final histology of HGD or SAC than preoperative biopsy. Further studies are warranted for establishing endoscopic features of submucosal carcinoma.

Risk factors for delayed bleeding, and the probable underlying mechanism involved, differed depending on the time elapsed between surgery and the bleeding episode.

Background and Aim: Endoscopic resection (ER) is widelyused as a minimally invasive therapy to remove superficial nonampullary duodenal tumor (SNADT). However, the indication criteria have not yet been clearly determined. At our institute, ER is done only for SNADT measuring ≤20 mm. We report our findings on the therapeutic outcomes of ER of SNADT. Methods:We carried out ER in 47 patients with SNADT. Indication criteria for ER included a lesion suspected as high-grade dysplasia or mucosal cancer and measuring ≤20 mm. The ER methods used to carry out en bloc resection were endoscopic mucosal resection (EMR: 17 lesions) or endoscopic submucosal dissection (ESD: 30 lesions). We then analyzed the therapeutic outcomes between them.Results: There were no significant differences between the EMR and ESD groups with regard to age, sex, location of the lesion, and histology. The most frequent gross types resected by EMR and ESD were 0-IIa and 0-IIc, respectively (P = 0.004). Median procedure time was significantly longer in ESD than in EMR, 79.5 and 9 min, respectively (P < 0.001). R0 resection was achieved in 10 cases by EMR (59%) and in 27 cases by ESD (90%) (P = 0.017). No complications occurred in cases that underwent EMR, but immediate and delayed perforations occurred in three patients who underwent ESD, although this difference was not statistically significant (P = 0.467).Conclusion: Using our indication criteria, which limited lesion size to ≤20 mm, satisfactory therapeutic outcomes of ER of SNADT were obtained.

LGD lesions show a low risk of progression to adenocarcinoma, but some risk of progression to HGD, which warrants careful follow-up biopsy. However, HGD lesions and large SNDAs≥20 mm in diameter show a high risk of progression to adenocarcinoma. Therefore, they should be treated immediately.

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Helicobacter pylori (H. pylori) leads to chronic gastritis and eventually causes gastric cancer. The prevalence of H. pylori infection is gradually decreasing with improvement of living conditions and eradication therapy. However, some reports have described cases of H. pylori-negative gastric cancers (HpNGC), and the prevalence was 0.42-5.4% of all gastric cancers. Diagnostic criteria of HpNGC vary among the different reports; thus, they have not yet been definitively established. We recommend negative findings in two or more methods that include endoscopic or pathological findings or serum pepsinogen test, and negative urease breath test or serum immunoglobulin G test and no eradication history the minimum criteria for diagnosis of HpNGC. The etiology of gastric cancers, excluding H. pylori infection, is known to be associated with several factors including lifestyle, viral infection, autoimmune disorder and germline mutations, but the main causal factor of HpNGC is still unclear. Regarding the characteristics of HpNGC, the undifferentiated type (UD-type) is more frequent than the differentiated type (D-type). The UD-type is mainly signet ring-cell carcinoma that presents as a discolored lesion in the lower or middle part of the stomach in relatively young patients. The gross type is flat or depressed. The D-type is mainly gastric adenocarcinoma of the fundic gland type that presents as a submucosal tumor-like or flat or depressed lesion in the middle and upper part of the stomach in relatively older patients. Early detection of HpNGC enables minimally invasive treatment which preserves the patient's quality of life. Endoscopists should fully understand the characteristics and endoscopic findings of HpNGC.