Sample Collection Methods in Upper Gastrointestinal Research.

In recent years, significant translational research advances have been made in the upper gastrointestinal (GI) research field. Endoscopic evaluation is a reasonable option for acquiring upper GI tissue for research purposes because it has minimal risk and can be applied to unresectable gastric cancer. The optimal number of biopsy samples and sample storage is crucial and might influence results. Furthermore, the methods for sample acquisition can be applied differently according to the research purpose; however, there have been few reports on methods for sample collection from endoscopic biopsies. In this review, we suggested a protocol for collecting study samples for upper GI research, including microbiome, DNA, RNA, protein, single-cell RNA sequencing, and organoid culture, through a comprehensive literature review. For microbiome analysis, one or two pieces of biopsied material obtained using standard endoscopic forceps may be sufficient. Additionally, 5 mL of gastric fluid and 3-4 mL of saliva is recommended for microbiome analyses. At least one gastric biopsy tissue is necessary for most DNA or RNA analyses, while proteomics analysis may require at least 2-3 biopsy tissues. Single cell-RNA sequencing requires at least 3-5 tissues and additional 1-2 tissues, if possible. For successful organoid culture, multiple sampling is necessary to improve the quality of specimens.

HERES, a lncRNA that regulates canonical and noncanonical Wnt signaling pathways via interaction with EZH2.

Wnt signaling through both canonical and noncanonical pathways plays a core role in development. Dysregulation of these pathways often causes cancer development and progression. Although the pathways independently contribute to the core processes, a regulatory molecule that commonly activates both of them has not yet been reported. Here, we describe a long noncoding RNA (lncRNA), HERES, that epigenetically regulates both canonical and noncanonical Wnt signaling pathways in esophageal squamous cell carcinoma (ESCC). For this study, we performed RNA-seq analysis on Korean ESCC patients and validated these results on a larger ESCC cohort to identify lncRNAs commonly dysregulated in ESCCs. Six of the dysregulated lncRNAs were significantly associated with the clinical outcomes of ESCC patients and defined 4 ESCC subclasses with different prognoses. HERES reduction repressed cell proliferation, migration, invasion, and colony formation in ESCC cell lines and tumor growth in xenograft models. HERES appears to be a transacting factor that regulates CACNA2D3, SFRP2, and CXXC4 simultaneously to activate Wnt signaling pathways through an interaction with EZH2 via its G-quadruple structure-like motif. Our results suggest that HERES holds substantial potential as a therapeutic target for ESCC and probably other cancers caused by defects in Wnt signaling pathways.

Comparison of the Efficacy of Polaprezinc Plus Proton Pump Inhibitor and Rebamipide Plus Proton Pump Inhibitor Treatments for Endoscopic Submucosal Dissection-induced Ulcers.

GOALS: We assessed the efficacy of polaprezinc plus proton pump inhibitor (PPI) treatment for endoscopic submucosal dissection (ESD)-induced ulcer healing compared with rebamipide plus PPI treatment. BACKGROUND: ESD has been widely used as a local treatment option that cures gastric neoplasms. However, it causes large and deep artificial ulcers, and there are no guidelines with regard to the optimal treatment durations and drug regimens for ESD-induced ulcers. Polaprezinc is effective for promoting ulcer healing and helps enhance the quality of ulcer healing. STUDY: Two hundred ten patients with ESD-induced ulcers were randomly allocated to treatment with polaprezinc (150 mg/d) plus pantoprazole (40 mg/d) or treatment with rebamipide (300 mg/d) plus pantoprazole (40 mg/d). We evaluated the ulcer healing rate and condition of the ulcer at 4 weeks after dissection. The χ2 or Fisher exact test and the Student t test were used. RESULTS: The ulcer healing rates at 4 weeks after dissection in the polaprezinc plus pantoprazole treatment group were not inferior compared with those in the rebamipide plus pantoprazole treatment group, both in the intention-to-treat analysis (90.3% and 91.4%, respectively, P=0.523) and per-protocol analysis (89.9% and 91.1%, respectively, P=0.531). The short procedure time was an independent predictive factor for a high ulcer healing rate (odds ratio: 0.975; 95% confidence interval: 0.958-0.993; P=0.006). CONCLUSION: The polaprezinc plus PPI treatment showed noninferiority to rebamipide plus PPI treatment in the ulcer healing rate at 4 weeks after ESD.

Prediction model for bleeding after endoscopic submucosal dissection of gastric neoplasms from a high-volume center.

BACKGROUND AND AIM: Bleeding after endoscopic submucosal dissection (ESD) is a main adverse event. To date, although there have been several studies about risk factors for post-ESD bleeding, there has been few predictive model for post-ESD bleeding with large volume cases. We aimed to design a prediction model for post-ESD bleeding using a classification tree model. METHODS: We analyzed a prospectively established cohort of patients with gastric neoplasms treated with ESD from 2007 to 2016. Baseline characteristics were collected for a total of 5080 patients, and the bleeding risk was estimated using variable statistical methods such as logistic regression, AdaBoost, and random forest. To investigate how bleeding was affected by independent predictors, the classification and regression tree (CART) method was used. The prediction tree developed for the cohort was internally validated. RESULTS: Post-ESD bleeding occurred in 262 of 5080 patients (5.1%). In multivariate logistic regression, ongoing antithrombotic use during the procedure, cancer pathology, and piecemeal resection were significant risk factors for post-ESD bleeding. In the CART model, the decisive variables were ongoing antithrombotic agent use, resected specimen size ≥49 mm, and patient age <62 years. The CART model accuracy was 94.9%, and the cross-validation accuracy was 94.8%. CONCLUSIONS: We developed a simple and easy-to-apply predictive tree model based on three risk factors that could help endoscopists identify patients at a high risk of bleeding. This model will enable clinicians to establish precise management strategies for patients at a high risk of bleeding and to prevent post-ESD bleeding.

Therapeutic potential of FLANC, a novel primate-specific long non-coding RNA in colorectal cancer.

OBJECTIVE: To investigate the function of a novel primate-specific long non-coding RNA (lncRNA), named FLANC, based on its genomic location (co-localised with a pyknon motif), and to characterise its potential as a biomarker and therapeutic target. DESIGN: FLANC expression was analysed in 349 tumours from four cohorts and correlated to clinical data. In a series of multiple in vitro and in vivo models and molecular analyses, we characterised the fundamental biological roles of this lncRNA. We further explored the therapeutic potential of targeting FLANC in a mouse model of colorectal cancer (CRC) metastases. RESULTS: FLANC, a primate-specific lncRNA feebly expressed in normal colon cells, was significantly upregulated in cancer cells compared with normal colon samples in two independent cohorts. High levels of FLANC were associated with poor survival in two additional independent CRC patient cohorts. Both in vitro and in vivo experiments demonstrated that the modulation of FLANC expression influenced cellular growth, apoptosis, migration, angiogenesis and metastases formation ability of CRC cells. In vivo pharmacological targeting of FLANC by administration of 1,2-dioleoyl-sn-glycero-3-phosphatidylcholine nanoparticles loaded with a specific small interfering RNA, induced significant decrease in metastases, without evident tissue toxicity or pro-inflammatory effects. Mechanistically, FLANC upregulated and prolonged the half-life of phosphorylated STAT3, inducing the overexpression of VEGFA, a key regulator of angiogenesis. CONCLUSIONS: Based on our findings, we discovered, FLANC as a novel primate-specific lncRNA that is highly upregulated in CRC cells and regulates metastases formation. Targeting primate-specific transcripts such as FLANC may represent a novel and low toxic therapeutic strategy for the treatment of patients.

Stratification of Postsurgical Computed Tomography Surveillance Based on the Extragastric Recurrence of Early Gastric Cancer.

OBJECTIVE: To stratify the postsurgical computed tomography (CT) surveillance based on a risk-scoring system for predicting extragastric recurrence after surgical resection of early gastric cancer (EGC). SUMMARY OF BACKGROUND DATA: Postsurgical CT surveillance should not be routinely performed in all patients because of the low incidence of extragastric recurrence and potential risk of radiation exposure. METHODS: Data from 3162 patients who underwent surgical resection for EGC were reviewed to develop a risk-scoring system to predict extragastric recurrence. Risk scores were based on the predictive factors for extragastric recurrence, which were determined using Cox proportional hazard regression model. The risk-scoring system was validated by Uno censoring adjusted C-index. External validation was performed using an independent dataset (n = 430). RESULTS: The overall incidence of extragastric recurrence was 1.4% (44/3162). Five risk factors (lymph node metastasis, indications for endoscopic resection, male sex, positive lymphovascular invasion, and elevated macroscopic type), which were significantly associated with extragastric recurrence, were incorporated into the risk-scoring system, and the patients were categorized into 2 risk groups. The 10-year extragastric recurrence-free survival differed significantly between low- and high-risk groups (99.7% vs 96.5%; P < 0.001). The predictive accuracy of the risk-scoring system in the development cohort was 0.870 [Uno C-index; 95% confidence interval (95% CI), 0.800-0.939]. Discrimination was good after internal (0.859) and external validation (0.782, 0.549-1.000). CONCLUSION: This risk-scoring system might be useful to predict extragastric recurrence of EGC after curative surgical resection. We suggest that postsurgical CT surveillance to detect extragastric recurrence should be avoided in the low-risk group.

Statins and metachronous recurrence after endoscopic resection of early gastric cancer: a nationwide Korean cohort study.

BACKGROUND: Statins have shown to reduce the risk of various cancers. However, their effects on metachronous recurrence (MR) after endoscopic resection (ER) for early gastric cancer (EGC) are unknown. We evaluate their effects on MR development after ER for EGC. METHODS: We selected 11,568 patients who received ER for EGC from 2002 to 2011 from the Korean National Health Insurance database and classified into 2 groups: control and statins using propensity score matching. Metachronous recurrence was defined as the second ER or gastrectomy performed 6 months after the first ER. RESULTS: Mean follow-up period was 8.8 ± 3.1 years. Statins showed a significantly lower incidence of MR than the control group (12.5% vs 2.2%, respectively, P < 0.01). After conducting competing risk analyses and time-dependent cox regression analysis considering immortal time bias, statins still showed a lower incidence rate of MR compared to that observed in the control group. For the multivariate analysis, statins remained significant (HR 0.17; 95% CI 0.13-0.24, P < 0.01). In the dose-response analysis, an inverse dose-response relationship was identified between MR and statins (P < 0.01). CONCLUSION: Statins was significantly associated with a reduced risk of MR after ER for EGC with an inverse dose-response relationship.

Comparison of general anesthesia and conscious sedation in procedure-related complications during esophageal endoscopic submucosal dissection.

BACKGROUND: Endoscopic submucosal dissection (ESD) has a favorable outcome, compared to esophagectomy, for early esophageal neoplasia. Recent studies used general anesthesia for esophageal ESD to minimize complications due to insufficient sedation and patient movement. We aimed to evaluate the safety of general anesthesia in comparison with conscious sedation provided by anesthesiologists for esophageal ESD. METHODS: We retrospectively reviewed the electronic medical records of 158 patients who underwent esophageal ESD under general anesthesia or conscious sedation provided by anesthesiologists. We evaluated the incidence of procedure-related complications, including perforation, post-ESD bleeding, cardiopulmonary adverse events (arrhythmia, hypotension, and hypoxemia), procedure failure, stricture, and new lung consolidation after ESD. Cases of frank perforation, post-ESD bleeding requiring a vigorous diagnostic approach, and cardiopulmonary adverse events were regarded as acute complications of ESD. RESULTS: Acute complications occurred only in the conscious sedation group (8/83 [9.6%] vs. 0/75 [0.0%]; p value = 0.007). The numbers of patients with frank perforation, post-ESD bleeding, and cardiopulmonary adverse events were four, one, and three, respectively. Moreover, new lung consolidation after ESD developed only in the conscious sedation group (7/83 [8.4%] vs. 0/75 [0.0%]; p value = 0.014). ESD failed in four patients in the conscious sedation group. The incidences of stricture that required stent insertion and hospital stay after ESD were comparable between the two groups. CONCLUSION: General anesthesia is associated with a lower incidence of acute procedure-related complications in esophageal ESD compared to conscious sedation provided by anesthesiologists. Therefore, we recommend general anesthesia as a safer option for esophageal ESD.

Evaluation of gastric microbiome and metagenomic function in patients with intestinal metaplasia using 16S rRNA gene sequencing.

BACKGROUND: Despite recent advances in studies on the gastric microbiome, the role of the non-Helicobacter pylori gastric microbiome in gastric carcinogenesis remains unclear. We evaluated the characteristics of the gastric microbiome and metagenomic functions in patients with IM. METHODS: Participants were classified into six groups according to disease status (chronic superficial gastritis [CSG], intestinal metaplasia [IM], and cancer) and H. pylori- infection status (H. pylori-positive and H. pylori-negative). The gastric microbiome was analyzed in mucosal tissues at the gastric antrum by 16S rRNA gene sequencing. Moreover, we assessed the metagenome including the type IV secretion system (T4SS) gene, as T4SS proteins are essential for transferring CagA from H. pylori- into the human gastric epithelium. RESULTS: Among the 138 included patients, 48, 9, 23, 14, 12, and 32 were classified into the H. pylori-negative CSG, H. pylori-negative IM, H. pylori-negative cancer, H. pylori-positive CSG, H. pylori-positive IM, and H. pylori-positive cancer groups, respectively. Cyanobacteria were predominant in the H. pylori-negative CSG group compared to in the H. pylori-negative IM and H. pylori-negative cancer groups (H. pylori-negative CSG vs H. pylori-negative IM vs H. pylori-negative cancer: 14.0% vs 4.2% vs 0.04%, P < 0.001). In contrast, Rhizobiales were commonly observed in the H. pylori-negative IM group (H. pylori-negative CSG vs H. pylori-negative IM vs H. pylori-negative cancer: 1.9% vs 15.4% vs 2.8%, P < 0.001). The relative abundance of Rhizobiales increased as H. pylori-infected stomachs progressed from gastritis to IM. In the H. pylori-negative IM group, genes encoding T4SS were prevalent among the metagenome. Additionally, after H. pylori- eradication therapy, the gastric microbiome was similar to the microbiome observed after spontaneous clearance of H. pylori-. CONCLUSIONS: The relative abundance of Rhizobiales was higher in patients with H. pylori-negative IM than in those with H. pylori-negative CSG or cancer. Additionally, T4SS genes were highly observed in the metagenome of patients with IM. Highly abundant T4SS proteins in these patients may promote gastric carcinogenesis.

Role of probe-based confocal laser endomicroscopy-targeted biopsy in the molecular and histopathological study of gastric cancer.

BACKGROUND AND AIM: A high yield of biopsy is mandatory to perform molecular genetic research with endoscopically obtained gastric cancer tissues. We evaluated whether probe-based confocal laser endomicroscopy (pCLE) can increase the yield of endoscopic biopsy for gastric cancer compared with white light endoscopy (WLE). METHODS: All lesions in the pCLE and WLE groups were initially evaluated through WLE. In the pCLE group, lesions were further examined through pCLE. In the pilot study, five and three biopsy specimens were obtained for histopathological examination and tumor marker analysis, respectively. In the confirmatory study, six biopsy specimens for histopathological evaluation were obtained. RESULTS: A total of 30 gastric cancers and 61 undifferentiated-type gastric cancers were analyzed in the pilot and confirmatory studies, respectively. The proportion of cancer cells in biopsy samples of poorly differentiated adenocarcinoma or signet ring cell carcinoma was higher in the pCLE group than in the WLE group in both the pilot and confirmatory studies (pilot: median proportion, 65% vs 30%, P = 0.010; confirmatory: mean ± standard deviation, 49.5 ± 29.3 vs 29.3 ± 13.7, P = 0.002). The expression ratio of tumor markers including carcinoembryonic antigen, GW112, HOX transcript antisense RNA, and H19 tended to be higher in the pCLE group than in the WLE group. CONCLUSION: Probe-based confocal laser endomicroscopy-targeted biopsy provided superior results in terms of the proportion of cancer cells in biopsy samples compared with WLE-targeted biopsy in gastric cancer with undifferentiated histology.

Long-term outcomes after noncurative endoscopic resection of early gastric cancer: the optimal time for additional endoscopic treatment.

BACKGROUND AND AIMS: We aimed to evaluate long-term outcomes with noncurative endoscopic submucosal dissection (ESD) for early gastric cancer (EGC) and surveillance strategies such as the optimal time for additional endoscopic treatment in patients with noncurative ESD. METHODS: Of 2527 patients who underwent gastric ESD for EGC, 512 (20.3%) patients with noncurative resection were reviewed. Noncurative resection is defined as positive resected margins on histology, lymphovascular infiltration, or beyond the expanded criteria for ESD. RESULTS: The mean ± standard deviation follow-up duration was 79.0 ± 55.7 months. A total of 264 patients (51.6%) and 50 patients (9.8%) underwent surgery and endoscopic treatment after noncurative resection, respectively, whereas 198 patients (38.7%) were observed. Cancer-specific survival and disease-free survival rates were significantly different among the surgery, other endoscopic treatment, and observation groups (96.7%, 86.8%, and 86.2%, respectively; P =.030; and 92.5%, 73.6%, and 63.0%, respectively; P < .001). When patients who underwent surgery were excluded, the disease-free survival rate of recurrence was not significantly different between the endoscopic treatment and observation groups (73.6% vs 63.0%; P = .548). To exclude the potential for the presence of lymph node metastasis, we further analyzed disease-free survival of local recurrence by comparing the patients with only a positive lateral resection margin. The disease-free survival rate was higher in the endoscopic treatment group than in the observation group (89.2% vs 69.1%; P = .023). Moreover, additional endoscopic treatment within 3 months showed significant associations with lower risk of local recurrence on multivariate analysis (hazard ratio, 0.017; 95% confidence interval, 0.002-0.260; P = .003). CONCLUSIONS: In patients with noncurative ESD, additional surgery showed a better long-term outcome; moreover, when a positive lateral resection margin was the only noncurative factor, additional endoscopic treatment within 3 months could be considered to improve disease-free survival.

Efficacy of hemostatic powder in preventing bleeding after gastric endoscopic submucosal dissection in high-risk patients.

BACKGROUND AND AIM: The prevention of post-endoscopic submucosal dissection (ESD) bleeding in high-risk patients is an important problem. This study evaluated the efficacy of polysaccharide hemostatic powder in preventing post-ESD bleeding in high-risk patients. METHODS: Patients at high risk for post-ESD bleeding were prospectively enrolled between December 2015 and July 2016. A high risk of post-ESD bleeding was considered if the patients were taking antithrombotic agents or had undergone a large resection (specimen size ≥ 40 mm). The endpoints were Forrest classification of the post-ESD ulcer on second-look endoscopy 2 days after the procedure and bleeding rates within 48 h and at 4 weeks. RESULTS: Forty-four patients underwent gastric ESD and treatment with hemostatic powder. Among them, 33 patients (70.5%) underwent large resection (≥ 40 mm) without antithrombotic therapy, and 13 patients (29.5%) received antithrombotic therapy. The mean resected specimen size was 55.3 ± 13.9 mm. The proportion of high-risk delayed bleeding lesions (Forrest IIa) at second-look endoscopy was 4.5% (2/44). The overall bleeding rate was 9.1% (4/44). There was no early bleeding event. The median (interquartile range) timing of bleeding after the procedure was 12.5 (interquartile range 10.3-15.5) days. The bleeding rate in the large resection (≥ 40 mm) group without antithrombotic therapy and the antithrombotic therapy group was 3.2% (1/33) and 23.1% (3/13), respectively. CONCLUSIONS: Hemostatic powder may be a promising new simple and effective method to prevent early post-ESD bleeding in high-risk patients, especially for those with larger resection. (Clinical trial registration number: NCT02625792).

Effect of the midazolam added with propofol-based sedation in esophagogastroduodenoscopy: A randomized trial.

BACKGROUND AND AIM: Although propofol has been widely used for sedation during esophagogastroduodenoscopy (EGD), adverse events including hypoxia and hypotension may be a concern in the propofol-based sedation. We aimed to analyze whether administration of midazolam would improve safety and efficacy of propofol-based sedation in EGD. METHODS: One hundred twenty patients who were scheduled to undergo diagnostic EGD were randomly assigned to either midazolam plus propofol (MP) or propofol alone groups. In the MP group, 2 mg of midazolam and 10 mg of propofol were given initially. In the propofol alone group, 40-60 mg of propofol was given initially. In both groups, 20 mg of propofol was given repeatedly to maintain moderate sedation as needed. Vital signs including oxygen saturation were monitored every 2 min. After the patients fully recovered, satisfaction score was investigated from endoscopists, nurses, and patients, respectively. RESULTS: The baseline characteristics did not differ between the MP and propofol alone groups. The mean required doses of propofol was (mean ± standard deviation) 0.3 ± 0.3 and 0.8 ± 0.2 mg/kg in the MP and propofol alone groups, respectively (P < 0.001). In addition, sedation-related adverse events and recovery time did not differ between the two groups. The proportion of satisfactory did not differ between the two groups (MP vs propofol alone; proportion; patient, 95.0% vs 93.3%, P > 0.999; endoscopist, 73.3% vs 80.0%, P = 0.064; nurse, 73.3% vs 76.7%, P = 0.551). CONCLUSION: Adding midazolam to propofol did not reduced the safety and efficacy, and sedation using propofol alone could be suitable for sedation during diagnostic EGD.

Effectiveness of the polysaccharide hemostatic powder in non-variceal upper gastrointestinal bleeding: Using propensity score matching.

BACKGROUND AND AIM: Recently, the application of hemostatic powder to the bleeding site has been used to treat active upper gastrointestinal bleeding (UGIB). We aimed to assess the effectiveness of the polysaccharide hemostatic powder (PHP) in patients with non-variceal UGIB. METHODS: We reviewed prospectively collected 40 patients with UGIB treated with PHP therapy between April 2016 and January 2017 (PHP group) and 303 patients with UGIB treated with conventional therapy between April 2012 and October 2014 (conventional therapy group). We compared the rate of successful hemostasis and the rebleeding between the two groups after as well as before propensity score matching using the Glasgow-Blatchford score and Forrest classification. RESULTS: Thirty patients treated with the PHP and 60 patients treated with conventional therapy were included in the matched groups. Baseline patient characteristics including comorbidities, vital signs, and bleeding scores were similar in the matched groups. The rate of immediate hemostasis and 7-day and 30-day rebleeding were also similar in the two groups before and after matching. In the subgroup analysis, no significant differences in immediate hemostasis or rebleeding rate were noted between PHP in monotherapy and PHP combined with a conventional hemostatic method. At 30 days after the therapy, there were no significant PHP-related complications or mortality. CONCLUSIONS: Given its safety, the PHP proved feasible for endoscopic treatment of UGIB, having similar effectiveness as that of conventional therapy. The PHP may become a promising hemostatic method for non-variceal UGIB.

Comparison of long-term clinical outcomes between endoscopic and surgical resection for early-stage adenocarcinoma of the esophagogastric junction.

BACKGROUND: The aim of this study was to analyze long-term clinical and oncologic outcomes in patients with early-stage adenocarcinoma of the esophagogastric junction (AEG) managed with either endoscopic resection (ER) or surgery. METHODS: The inclusion criteria were AEG, meeting classic or expanded indications for ER of early gastric cancer, and complete resection. A total of 66 patients with Siewert type II AEG were included (ER group, n = 38; vs. surgery group, n = 28). RESULTS: The mean age of the ER group was greater than that of the surgery group (mean ± SD, 66.9 ± 9.7 vs. 58.5 ± 10.4 years, respectively; p = 0.001). Compared to the ER group, macroscopically flat or depressed-type lesions were more common (47.4 vs. 89.3%; p = 0.001), and mean lesion size was larger in the surgery group (13.3 ± 8.4 vs. 18.6 ± 11.0 mm; p = 0.039). One intensive care unit admission and subsequent surgery-related death occurred in the surgery group (1/28 vs. 0/38 in the ER group; p = 0.424). During follow-up, recurrence was detected in both groups (4/38 vs. 1/28; p = 0.385). Overall survival and 5-year disease-free survival did not differ between the groups (93.3 vs. 92.9%; p = 0.282 and 88.0 vs. 100.0%; p = 0.066). CONCLUSIONS: Once complete resection is achieved in patients with AEG who met the expanded criteria for endoscopic submucosal dissection of gastric cancer, there was no significant difference in clinical outcomes between ER and surgery.

Long-term outcomes of endoscopic submucosal dissection in comparison to surgery in undifferentiated-type intramucosal gastric cancer using propensity score analysis.

BACKGROUND: The treatment of intramucosal early gastric cancer with undifferentiated-type histologies (UD-EGCs) using endoscopic submucosal dissection (ESD) is controversial. This study aimed to compare the clinical and oncologic long-term outcomes of ESD and surgery for UD-EGCs. METHODS: A prospectively collected database of patients who underwent ESD or surgery between January 2006 and December 2012 was established. Patients who diagnosed with UD-EGC and satisfied the expanded indications of ESD were included. Clinical data from 111 patients treated with ESD and 382 patients underwent surgery were analyzed, and 1-1 propensity score-matched 81 pairs of patients were also compared. RESULTS: In both groups, two-thirds of the UD-EGCs had signet ring cell (SRC)-type histology and about 90% of UD-EGCs were flat or depressed types. The mean size of tumors was smaller in ESD group (9.7 vs. 13.2 mm; P < 0.001). After propensity score-matched, case-matching covariates were not significantly different between the groups. Disease-free survival (DFS) was significantly shorter in the ESD group, but overall survival (OS) was not different between the two groups both in overall comparison (DFS; P < 0.001 and OS; P = 0.078) and propensity score-matched analysis (DFS; P < 0.001 and OS; P = 0.850). According to histologic type, OS of SRC histology was not different between the group, both in overall comparison and propensity score-matched analysis (P = 0.286 and P = 0.210). On the other hands, OS of poorly differentiated adenocarcinoma was significantly shorter in ESD group in overall comparison (P = 0.007), but was not as so in propensity score-matched analysis (P = 0.088). CONCLUSIONS: ESD might be a complementary option for the treatment of UD-EGCs, especially in those with SRC-type histology based on strict expanded indications. Nonetheless, close endoscopic surveillance is required because of a high incidence of intragastric recurrence.

Comparative study between endoscopic submucosal dissection and surgery in patients with early gastric cancer.

BACKGROUND: Endoscopic submucosal dissection (ESD) is accepted as a standard treatment in patients with early gastric cancer (EGC) who have a negligible risk of lymph node metastasis. The aim of this study was to compare the short-term and long-term outcomes between ESD and surgery in patients with EGC that fulfilled the expanded indication of ESD on their final pathologic report. METHODS: We reviewed the clinical data of patients who underwent gastric ESD and surgery between January 2007 and December 2012. Patients with pathologically confirmed EGC that fulfilled the expanded indication of ESD on their final pathologic report were analyzed. RESULTS: Among 2023 patients, 817 (40.4%) underwent ESD and 1206 (59.6%) underwent surgery. The proportion of cases meeting the absolute indication was significantly higher in the ESD group than in the surgery group (66.0 vs. 26.2%). Lesions on the middle third, >3 cm in size, flat or depressed, and of undifferentiated histology were significantly more common in the surgery group than in the ESD group. The ESD group showed lower acute complication rates [8.1% (66 of 817) vs. 18.1% (218 of 1206), P ≤ 0.001] and procedure-related mortality [0 vs. 0.3% (4 of 1206), P = 0.153] than the surgical group. The annual incidence of recurrent gastric cancer was 2.18% in the ESD group and 0.19% in the surgery group. The 5-year overall and disease-specific survival rates were not significantly different between the ESD group and the surgery group (overall survival: 96.4 vs. 97.2%, P = 0.423; disease-specific survival: 99.6 vs. 99.2%, P = 0.203). CONCLUSIONS: Although EGC lesions had poorer features in the surgery group than in the ESD group, ESD was comparable to surgery for EGCs that fulfilled the expanded indication of ESD, with lower rates of acute complication and comparable overall survival.

MALAT1 promoted invasiveness of gastric adenocarcinoma.

BACKGROUND: Gastric cancer is the second leading cause of cancer globally, and the mechanism of its pathogenesis is still largely unknown. Recently, non-coding RNAs have been recognized to promote metastasis in various cancers, including gastric cancer. METHODS: We found that metastasis associated lung adenocarcinoma transcript-1 (MALAT1) is upregulated in gastric cancer tissue compared to adjacent normal tissue, as determined by microarray and subsequent qRT-PCR, then investigated the impact of MALAT1 on apoptosis, cell proliferation, and the cell cycle to dissect the carcinogenesis of gastric cancer, and examined mechanisms of invasion and metastasis. Expression of MALAT1 and U6 was determined by SYBR qRT-PCR in nine-teen gastric cancer cell lines and fifty fresh samples of cancer tissue and adjacent tissues. Downregulation of MALAT1 was accomplished with two different siRNAs. Cell proliferation was determined after treatment with these siRNAs. FACS using PI/Annexin-V staining was carried out. To analyze the invasiveness, a scratch wound-healing assay and a Matrigel invasion assay were performed. Cancer related gene expression assay was done after transfection of siR- MALAT1. RESULTS: The expression of MALAT1 was significantly elevated in various gastric cancer cell lines and gastric cancer tissues compared to normal cell lines and tissues (p < 0.01). siR-MALAT1 significantly reduced viable AGS cell numbers and induced apoptosis (p < 0.05). Deep invasion of tumor (advanced T stages) was more common in the high MALAT1-level group (p = 0.039). siR-MALAT1 significantly decreased AGS cell invasiveness and migration. siR-MALAT1 reduced expression of snail and N-cadherin, and elevated E-cadherin. The Wnt/ß-catenin related genes were significantly decreased by transfection of siRNA MALAT1. MALAT1 is involved in gastric carcinogenesis via inhibition of apoptosis and promotes invasiveness via the epithelial-to-mesenchymal transition. CONCLUSIONS: In our study, we found that deregulation of MALAT1 could be involved in both tumorigenesis and invasiveness in gastric cancer cells.

Prediction model for non-curative resection of endoscopic submucosal dissection in patients with early gastric cancer.

BACKGROUND AND AIMS: Endoscopic submucosal dissection (ESD) is a useful method for complete resection of early gastric cancer (EGC). However, there are still some patients who undergo additional gastrectomy after ESD because of non-curative resection. There is no model that can accurately predict non-curative resection of ESD. We aimed to create a model for predicting non-curative resection of ESD in patients with EGC. PATIENTS AND METHODS: We reviewed the medical records, including all gross findings of EGC, of patients who underwent ESD for EGCs. We divided the patients into a non-curative resection group and a curative resection group. The clinicopathologic characteristics were compared between the groups to identify the risk factors for non-curative resection of ESD. We created a scoring system based on logistic regression modeling and bootstrap validation. RESULTS: Of 1639 patients who had undergone ESD for EGCs, 272 were identified as being treated non-curatively with ESD. A large tumor size (≥20 mm), tumor location in the upper body of the stomach, the presence of ulcer, fusion of gastric folds, the absence of mucosal nodularity, spontaneous bleeding, and undifferentiated tumor histology were associated with non-curative resection of ESD. Points of risk scores were assigned for these variables based on the ß coefficient as follows: tumor size (≥20 mm), 2 points; tumor location in the upper body of the stomach, 1 point; ulcer, 2 points; fusion of gastric folds, 2 points; absence of mucosal nodularity, 1 point; spontaneous bleeding, 1 point; and undifferentiated histology, 2 points. Our risk scoring model showed good discriminatory performance on internal validation (bootstrap-corrected area under the receiver operating characteristic curve, 0.7004; 95% confidence interval, 0.6655-0.7353). CONCLUSIONS: We developed a validated prediction model that can be used to identify patients who will undergo non-curative resection of ESD. Our prediction model can provide useful information for making decisions about the treatment of EGC before performing ESD.