Present and future status of gastric cancer surgery

LINC00355 promotes gastric carcinogenesis by scaffolding p300 to activate CDC42 transcription and enhancing HNRNPA2B1 to stabilize CDC42 mRNA dependent on m6A

LINC00355 is involved in the tumorigenesis of several types of cancer. We verified that LINC00355 is upregulated in gastric cancer (GC) and contributes to GC cells' proliferation and metastasis. RNA sequencing (RNA-seq) and rescue assays suggested that LINC00355 controls gastric carcinogenesis by regulating the expression of cell division cycle 42 (CDC42) guanosine triphosphatase (GTPases), thereby activating their downstream pathways. Most previous studies have shown that LINC00355 acts as a ceRNA by sponging miRNAs to modulate downstream gene expression. Our group focus on epigenetic regulatory potential of LINC00355 in gene expression. Mechanistically, LINC00355 binds to p300 histone acetyltransferase, specifying the histone modification pattern on the CDC42 promoter to activate CDC42 transcription, thereby altering GC cell biology. In addition, HNRNPA2B1, which is upregulated by LINC00355, recognizes the N6-methyladenosine (m6A) sites of CDC42 and enhances the stability of CDC42 mRNA transcripts. Therefore, LINC00355 is mechanistically, functionally, and clinically oncogenic in GC cells.

CC chemokine receptors are prognostic indicators of gastric cancer and are associated with immune infiltration

BACKGROUND

CC chemokine receptors are responsible for regulating the tumor microenvironment (TME) and participating in carcinogenesis and tumor advancement. However, no functional study has investigated CC chemokine receptors in gastric cancer (GC) prognosis, risk, immunotherapy, or other treatments.

METHODS

We conducted a bioinformatics analysis on GC data using online databases, including the Human Protein Atlas (HPA), Kaplan-Meier (KM) plotter, GeneMANIA, MethSurv, the University of ALabama at Birmingham CANcer (UALCAN) Data Analysis Portal, Gene Set Cancer Analysis (GSCA), cBioportal, and Tumor IMmune Estimation Resource (TIMER).

RESULTS

We noted that CC chemokine receptor expression correlated with survival in GC. CC chemokine receptor expression was also strongly linked to different tumor-infiltrating immune cells. Additionally, CC chemokine receptors were found to be broadly drug-resistant in GC.

CONCLUSION

Our study identifed CC chemokine receptor expression helped in predicting the prognosis of patients diagnosed with GC. The expression level of the CC chemokine receptors was also positively related to multiple tumor-infiltrating lymphocytes (TILs). These findings provide evidence to monitor patients with GC using CC chemokine receptors, which can be used as an effective biomarker for predicting the disease prognosis and be regarded as a therapeutic target for modulating the tumor immune microenvironment.

Impact of surgical resection on the survival in Mexican patients with gastric cancer: A meta-analysis and systematic review

BACKGROUND

Gastric cancer (GC) is one of the most frequent cancer types in Mexico. The primary method used as a treatment is surgical resection. The role of surgery in increasing survival is controversial. This study aimed to determine whether surgical resection increases the survival of patients with GC in a Mexican population.

METHODS

A systematic review of literature searches (Evidence-based MEDLINE/PubMed, Web of Science, Cochrane Library, and SciELO) and meta-analysis were performed based on the Preferred Reporting Items for Systematic Reviews and Meta-Analysis criteria. The published articles from 2000 to the current time were divided into cross-sectional and randomized studies. The inclusion criteria were survival, surgical resections, patients treated in Mexico, and primary GC. The effect estimation was calculated using the risk ratio (RR). The random-effects model and a confidence interval (CI) of 95% were used.

RESULTS

The RR of the pooled studies was 1.09 (95% CI, 0.71-1.67). RR of 0.82 (95% CI, 0.63-1.07) was obtained in cross-sectional studies, and randomized studies showed a RR of 2.08 (95% CI, 0.25-17.07).

CONCLUSION

This work is the first systematic study that assesses the role of surgery on the survival of patients with GC in the Mexican population, the results showed that surgical resection did not improve survival in patients with GC.

A comprehensive review of the role of lncRNAs in gastric cancer (GC) pathogenesis, immune regulation, and their clinical applications

Gastric cancer (GC) is the fifth most common malignant tumor and the third leading cause of cancer-related deaths worldwide. Although numerous studies have been conducted on advanced GC, the molecular mechanisms behind it remain obscure. Long non-coding RNAs (lncRNAs) are a family of RNA transcripts capable of regulating target genes at transcriptional, post-transcriptional, and translational stages. They do this by modifying mRNAs, miRNAs, and proteins. These RNAs are critical regulators of many biological processes, including gene epigenetics, transcription, and post-transcriptional levels. This article highlights recent results on lncRNAs involved in drug resistance, proliferation, migration, angiogenesis, apoptosis, autophagy, and immune response in GC. The potential clinical implications of lncRNAs as biomarkers and therapeutic targets in GC are also discussed.

Immune-Related lncRNAs Pairs to Construct a Novel Signature for Predicting Prognosis in Gastric Cancer

Background

Immune-related long non-coding RNAs (irlncRNAs) appear valuable in predicting prognosis in patients with cancer. In this study, we used a fresh modeling algorithm to construct irlncRNAs signature and then assessed its predictive value for prognosis, tumor immune infiltration, and chemotherapy efficacy in gastric cancer (GC) patients.

Materials and Methods

The raw transcriptome data were extracted from the Cancer Genome Atlas (TCGA). Patients were randomly divided into the training and testing cohort. irlncRNAs were identified through co-expression analysis, after which differentially expressed irlncRNA (DEirlncRNA) pairs were identified. Next, we developed a model to distinguish between high- or low-risk groups in GC patients through univariate and LASSO regression analyses. A ROC curve was used to verify this model. After subgrouping patients according to the median risk score, we investigated the connection between the risk score of GC and clinicopathological characteristics. Functional enrichment analysis was also performed.

Results

We find that the results indicate that immune-related lncRNA signaling has essential value in predicting prognosis, and it may be potential to measure the Efficacy for immunotherapy. This feature may be a guide to the selection of GC immunotherapy.

Conclusion

Our data revealed that immune-related lncRNA signaling had essential value in predicting prognosis, and it may be potentially used to measure the efficacy for immunotherapy. This feature may also be used to guide the selection of GC immunotherapy.

C-Myc-activated long non-coding RNA LINC01050 promotes gastric cancer growth and metastasis by sponging miR-7161-3p to regulate SPZ1 expression

BACKGROUND

Growing evidence shows that long non-coding RNAs (lncRNAs) play significant roles in cancer development. However, the functions of most lncRNAs in human gastric cancer are still not fully understood. Here, we explored the role of a novel c-Myc-activated lncRNA, LINC01050, in gastric cancer progression.

METHODS

The expression of LINC01050 in the context of gastric cancer was assessed using The Cancer Genome Atlas datasets. Its functions in gastric cancer were investigated through gain- and loss-of-function experiments combined with the Cell Counting Kit-8 assays, colony-forming assays, Transwell assays, flow cytometry, Western blot analyses, and xenograft tumor and mouse metastasis models. Potential LINC01050 transcription activators were screened via bioinformatics and validated by chromatin immunoprecipitation and luciferase assays. The interaction between LINC01050 and miR-7161-3p and the targets of miR-7161-3p were predicted by bioinformatics analysis and confirmed by a luciferase assay, RNA immunoprecipitation, RNA pull-down, and rescue experiments.

RESULTS

LINC01050 was significantly up-regulated in gastric cancer, and its high expression was positively correlated with a poor prognosis. The transcription factor c-Myc was found to directly bind to the LINC01050 promoter region and activate its transcription. Furthermore, overexpression of LINC01050 was confirmed to promote gastric cancer cell proliferation, migration, invasion, and epithelial-mesenchymal transition in vitro and tumor growth in vivo. At the same time, its knockdown inhibited gastric cancer cell proliferation, migration, invasion, and epithelial-mesenchymal transition in vitro along with tumor growth and metastasis in vivo. Moreover, mechanistic investigations revealed that LINC01050 functions as a molecular sponge to absorb cytosolic miR-7161-3p, which reduces the miR-7161-3p-mediated translational repression of SPZ1, thus contributing to gastric cancer progression.

CONCLUSIONS

Taken together, our results identified a novel gastric cancer-associated lncRNA, LINC01050, which is activated by c-Myc. LINC01050 may be considered a potential therapeutic target for gastric cancer.

Short-Term Clinical Efficacy of Neoadjuvant Chemotherapy Combined With Laparoscopic Gastrectomy for Locally Advanced Siewert Type II and III Adenocarcinoma of the Esophagogastric Junction: A Retrospective, Propensity Score-Matched Study

Background

Laparoscopic gastrectomy (LG) has been increasingly used for the treatment of locally advanced Siewert type II and III adenocarcinoma of the esophagogastric junction (AEG). However, whether LG can achieve the same short-term efficacy in the treatment of patients who receive neoadjuvant chemotherapy (NACT) remains controversial. Thus, the aim of this study was to investigate the clinical outcomes of NACT combined with LG for Siewert type II and III AEG.

Methods

This retrospective study identified patients with locally advanced Siewert type II and III AEG diagnosed between May 2011 and October 2020 using the clinical tumor-node-metastasis (cTNM) staging system. The short-term outcomes were compared between the matched groups using a 1:3 propensity score matching (PSM) method, which was performed to reduce bias in patient selection.

Results

After PSM, 164 patients were selected, including 41 in the NACT group and 123 in the LG group. The baseline characteristics were similar between the two groups. Compared with the LG group, the NACT group exhibit a smaller tumor size and significantly less advanced pathological tumor classification and nodal classification stages. The time to first flatus of the NACT group was significantly shorter, but the hospital stay was significantly longer than that of the LG group. The NACT group showed similar overall (29.3% vs 25.2%, P=0.683), systemic (24.4% vs 21.1%, P=0.663), local (12.2% vs 9.8%, P=0.767), minor (19.5% vs 19.5%, P=1.000) and major (9.8% vs 5.7%, P=0.470) complications as the LG group. Subgroup analyses showed no significant differences in most stratified parameters. Operation time≥ 300 minutes was identified as an independent risk factor for overall complications. Age≥ 60 years was identified as an independent risk factor for major complications.

Conclusion

NACT combined with LG for AEG does not increase the risk of postoperative morbidity and mortality compared with LG.

Knockdown of Long Non-coding RNA LINC00200 Inhibits Gastric Cancer Progression by Regulating miR-143-3p/SERPINE1 Axis

BACKGROUND

An increasing number of studies have found that long non-coding RNAs (lncRNAs) play an important role in carcinogenesis and tumor progression, whereas their molecular mechanisms of function remain largely unknown.

AIMS

This study was aimed to explore the biological function and underlying mechanism of a new lncRNA LINC00200 in gastric cancer (GC).

METHODS

qRT-PCR analysis was conducted to examine the LINC00200 expression level in both GC tissues and cell lines. Functional assays were carried out to detect the effect of LINC00200 on GC cell proliferation, invasion and migration. The interaction between LINC00200 and miR-143-3p was confirmed by luciferase reporter assays. Rescue assays were performed to confirm the influence of LINC00200-miR-143-3p-SERPINE1 axis on GC development.

RESULTS

LINC00200 was found to be upregulated in GC tissues and cell lines. Moreover, knockdown of LINC00200 suppressed GC cell proliferation, invasion and migration in vitro and inhibited tumorigenesis in mouse xenografts. Finally, mechanism research indicated that LINC00200 functioned as a ceRNA to sponge for miR-143-3p, thus leading to the disinhibition of its target gene SERPINE1.

CONCLUSIONS

LINC00200 is significantly overexpressed in GC and accelerates GC progression through regulating miR-143-3p/SERPINE1 axis. Our results may provide a potential diagnostic biomarker and therapeutic target for the management of GC patients.

Surgical Management of Gastric Cancer: A Systematic Review

Gastric cancer is the fifth most common cancer worldwide, and it is responsible for 7.7% of all cancer deaths. Despite advances in the field of oncology, where radiotherapy, neo and adjuvant chemotherapy may improve the outcome, the only treatment with curative intent is represented by surgery as part of a multimodal therapy. Two concepts may be adopted in appropriate cases, neoadjuvant treatment before gastrectomy (G) or primary surgical resection followed by chemotherapy. Such an approach, combined with early detection and better screening, has led to a decrease in the overall incidence of gastric cancer. Unfortunately, malignant tumors of the stomach are often diagnosed in locally advanced or metastatic stages when the median overall survival remains poor. Surgical care in these cases must be provided by a multidisciplinary team in a high-volume center. Important surgical aspects such as optimum resection margins, surgical technique, and number of harvested lymph nodes are important factors for patient outcomes. The standardization of surgical treatment of gastric cancer in accordance with the patient’s profile is of decisive importance for a better outcome. This review aims to summarize the current standards in the surgical treatment of gastric cancer.

Impact of the introduction of formal D2 lymphadenectomy for gastric cancer in a Western setting

Background

Two members from an academic tertiary hospital went to the National Cancer Institute in Tokyo, Japan, to learn how to perform an adequate D2 lymphadenectomy and to then introduce this technique in the surgical care of patients undergoing surgery for gastric cancer at a Western hospital. We aimed to compare the perioperative outcomes and long-term survival of Western patients who underwent gastric resection, performed by these 2 surgeons, before and after the surgeons’ short-course technical training in Japan.

Methods

We conducted a retrospective comparative study of all patients (n = 27 before training and n = 79 after training) who underwent gastric resection for cancer by the same 2 surgeons between September 2007 and December 2017 at the Centre Hospitalier Universitaire de Québec — Université Laval (Québec, Canada). We collected data on patient demographic, clinical, surgical, pathological and treatment characteristics, as well as long-term survival and complications.

Results

In the post-training group, the number of sampled lymph nodes was higher (median 33 v. 14, p < 0.0001), but this increase did not result in a higher number of histologically positive lymph nodes (p = 0.35). The rate of complications was lower in the post-training group (15.2% v. 48.2%, p = 0.002). The hospital stay was shorter in the post-training group (11 [standard deviation (SD) 7] v. 23 [SD 45] d, p = 0.03). The median survival was higher in the post-training group (47 v. 29 mo, p = 0.03).

Conclusion

These results suggest that a short-course technical training in D2 lymphadenectomy, completed in Japan, improved lymph node sampling, decreased postoperative complications and improved survival of patients undergoing surgery for gastric cancer in a Western setting.

A risk score model with five long non-coding RNAs for predicting prognosis in gastric cancer: an integrated analysis combining TCGA and GEO datasets

Background

Gastric cancer (GC) is one of the most common carcinomas of the digestive tract, and the prognosis for these patients may be poor. There is evidence that some long non-coding RNAs(lncRNAs) can predict the prognosis of patients with GC. However, few lncRNA signatures have been used to predict prognosis. Herein, we aimed to construct a risk score model based on the expression of five lncRNAs to predict the prognosis of patients with GC and provide new potential therapeutic targets.

Methods

We performed differentially expressed and survival analyses to identify differentially expressed survival-ralated lncRNAs by using GC patient expression profile data from The Cancer Genome Atlas (TCGA) database. We then established a formula including five lncRNAs to predict the prognosis of patients with GC. In addition, to verify the prognostic value of this risk score model, two independent Gene Expression Omnibus (GEO) datasets, GSE62254 (N = 300) and GSE15459 (N = 200), were employed as validation groups.

Results

Based on the characteristics of five lncRNAs, patients with GC were divided into high or low risk subgroups. The prognostic value of the risk score model with five lncRNAs was confirmed in both TCGA and the two independent GEO datasets. Furthermore, stratification analysis results showed that this model had an independent prognostic value in patients with stage II-IV GC. We constructed a nomogram model combining clinical factors and the five lncRNAs to increase the accuracy of prognostic prediction. Enrichment analysis based on the Kyoto Encyclopedia of Genes and Genomes (KEGG) suggested that the five lncRNAs are associated with multiple cancer occurrence and progression-related pathways.

Conclusion

The risk score model including five lncRNAs can predict the prognosis of patients with GC, especially those with stage II-IV, and may provide potential therapeutic targets in future.

MicroRNA-1297 inhibits proliferation and promotes apoptosis in gastric cancer cells by downregulating CDC6 expression

Gastric cancer (GC), one of the most common malignant tumors and the second most common leading cause of cancer-related death worldwide, is a biologically heterogeneous disease accompanied by various genetic and epigenetic alterations. However, the molecular mechanisms underlying this disease are complex and not completely understood. Increasing studies have shown that aberrant microRNA (miRNA) expression is associated with GC tumorigenesis and growth. MiR-1297 has been confirmed to be a cancer suppressor in diverse tumors in humans. However, to date, the function and mechanism of miR-1297 in GC have not been determined. Here, we found that the expression of miR-1297 was significantly reduced in GC tissues or GC cell lines compared with paracarcinoma normal tissue or normal cell lines. Exogenic overexpression of miR-1297 in GC cell lines can inhibit cell proliferation and colony formation and induce apoptosis, and inhibition of miR-1297 in GC cell lines can promote cell proliferation and colony formation, and reduce apoptosis in vitro. We further confirmed that miR-1297 acted as a tumor suppressor through targeting cell division control protein 6 (CDC6) in GC. Moreover, the inverse relationship between miR-1297 and CDC6 was verified in GC cell lines. Our results indicated that miR-1297 is a potent tumor suppressor in GC, and its antiproliferative and gene-regulatory effects are, in part, mediated through its downstream target gene, CDC6. These findings implied that miR-1297 might be used as a novel therapeutic target of GC.

KLF5-Modulated lncRNA NEAT1 Contributes to Tumorigenesis by Acting as a Scaffold for BRG1 to Silence GADD45A in Gastric Cancer

Long noncoding RNAs (lncRNAs), genomic "dark matter," are deeply involved in diverse biological processes. The lncRNA nuclear paraspeckle assembly transcript 1 (NEAT1) is a highly participatory lncRNA; however, its roles in gastric cancer (GC) remain largely unexplored. Here, we demonstrated that the expression of NEAT1 was significantly increased and negatively correlated with prognosis in GC. Subsequent experiments confirmed that KLF5 can induce NEAT1 expression by binding to the NEAT1 promoter region. Further experiments revealed that NEAT1 silencing significantly suppressed cell proliferation both in vitro and in vivo and induced apoptosis. We used mRNA sequencing (mRNA-seq) to identify the preferentially affected genes linked to cell proliferation in cells with NEAT1 knockdown. Mechanistically, NEAT1 bound BRG1 (SMARCA4) directly, modulating H3K27me3 and H3K4me3 in the GADD45A promoter to regulate GADD45A-dependent G2/M cell cycle progression. In addition, BRG1 was significantly upregulated and correlated with outcomes in GC; moreover, it promoted cell proliferation both in vitro and in vivo. Taken together, our data support the importance of NEAT1 in promoting GC tumorigenesis and indicate that NEAT1 might be a diagnostic and therapeutic target in GC.

Long Noncoding RNASBF2-AS1 Promotes Gastric Cancer Progression via Regulating miR-545/EMS1 Axis

Objective

Long noncoding RNA (LncRNA) SBF2-AS1 was reportedly to function as an oncogene in several types of cancers, such as hepatocellular carcinoma, nonsmall cell lung cancer, glioma, and colorectal cancer. However, the biological roles and regulatory mechanisms of SBF2-AS1 in gastric cancer (GC) are unknown.

Methods

The expression of SBF2-AS1 and miR-545 were examined in GC tissues and cell lines via real-time quantitative PCR. The relationship of SBF2-AS1 with miR-545 was verified via dual-luciferase reporter gene assay and RNA immunoprecipitation. The influences of SBF2-AS1 on cell proliferation, migration, and invasion were determined using cell counting Kit-8 (CCK-8), wound healing, and transwell invasion assays, respectively.

Results

LncRNA SBF2-AS1 expression was upregulated in GC tissues, especially in advanced clinical stage cases. Moreover, increased SBF2-AS1 indicated a poor survival rate. Functionally, the downregulation of SBF2-AS1 by siRNA in GC cells suppressed the proliferation, migration, and invasion. In terms of mechanism, SBF2-AS1 can directly bind to miR-545 and regulate its expression. Moreover, SBF2-AS1 knockdown significantly decreased the expression of EMS1, which was the direct target of miR-545. Importantly, inhibition of miR-545 or overexpression of EMS1 partially reversed SBF2-AS1-depletion-caused suppression on proliferation, migration, and invasion.

Conclusion

These findings elucidated a crucial role of SBF2-AS1 as a miR-545 sponge in GC cells, suggesting that SBF2-AS1 might be a potential target for GC.

Clinicopathological Evaluation of Gastric Signet Ring Cell Carcinoma: Our Experience

Aim

Gastric cancer is one of the most common cancers worldwide. In Turkey, stomach cancer is ranked 5th among men and 8th among women in all cancers and is located in the forefront in cancer-related deaths. Signet ring cell adenocarcinoma, which is the histopathological subtype of gastric cancer, has a poor prognosis. The incidence of signet ring cell adenocarcinoma is rising. In the present study, we aimed to describe the clinicopathologic features of signet ring cell adenocarcinoma.

Materials and Methods

A total of 79 patients with 30 being female (38%) and 49 male (62%) who were diagnosed with gastric signet ring cell adenocarcinoma in the Medical Oncology Department of Ankara Numune Training and Research Hospital between January 2004 and October 2015 were retrospectively evaluated.

Results

The baseline demographic characteristics of the patients, such as tumor localization, tumor stage, preoperative serum tumor markers, and treatment type (surgery and chemotherapy regimen), and the effects of these variables on survival and mortality were evaluated. Total surgery, stage III disease, moderate to poor grade, preoperative serum CA 19-9 and CEA levels were found as independent predictors of progression risk (p < 0.05). Each 1 ng/mL increase in preoperative serum CEA level was found to increase the risk of progression by 1.20 folds. Again, each 1 U/mL in preoperative serum CA 19-9 level was found to increase the risk of progression and mortality by 1.06 folds.

Conclusion

The clinicopathologic features of signet ring cell stomach cancer were described. Tumor localization and disease, CA 19-9 and CEA levels, and treatment type (surgery and chemotherapy regimen) were effective on survival and mortality. However, further studies with larger patient groups are needed on this issue.

How to cite this article

Altay SB, Akkurt G, Yılmaz N, et al. Clinicopathological Evaluation of Gastric Signet Ring Cell Carcinoma: Our Experience. Euroasian J Hepato-Gastroenterol 2020;10(2):76–84.

The Down-Regulation of lncRNA PCAT18 Promotes the Progression of Gastric Cancer via MiR-107/PTEN/PI3K/AKT Signaling Pathway

Purpose

LncRNAs are important regulators in cancers. In this study, we investigated the role of lncRNA PCAT18 in gastric cancer (GC).

Patients and Methods

The level of PCAT18 in GC tissues and cells was determined by qRT-PCR. The cellular behaviors of GC cells with knockdown or overexpression of PCAT18 were respectively detected by CCK-8 assays, colony formation assays, flow cytometry and Western blot. A GC mice model was established by subcutaneous injection of MGC-803 and HGC-27 cells with the knockdown or overexpression of PCAT18. The tumor size and weight were measured, and IHC was performed to determine ki-67 level. Predicted by bioinformatics software and confirmed by dual-luciferase reporter assay, PCAT18 was involved in miR-107/PTEN axis, thus, the expression of and relationship among PCAT18, miR-107 and PTEN pathway were explored in clinical cases and GC cell lines. Rescue assay was performed in GC cells by co-transfection with miR-107 mimic or PCAT18. The PTEN/PI3K/AKT pathway was then detected by Western blot.

Results

PCAT18 was down-regulated in GC tissues and cells, and it had a significant diagnostic value for GC. The expression of PCAT18 was highly associated with tumor size, and PCAT18 was found to inhibit GC growth in vitro and in vivo. It was also found that PCAT18 was involved in PTEN/PI3K/AKT signaling pathway through targeting miR-107.

Conclusion

PCAT18 inhibits the progression of GC via miR-107/PTEN/PI3K/AKT signaling pathway. Additionally, PCAT18 is possibly a promising target for treatment of GC.

Non-coding RNA in drug resistance of gastric cancer

Gastric cancer (GC) is the third leading cause of cancer-related mortality worldwide. The poorly prognosis and survival of GC are due to diagnose in an advanced, non-curable stage and with a limited response to chemotherapy. The acquisition of drug resistance accounts for the majority of therapy failure of chemotherapy in GC patients. Although the mechanisms of anticancer drug resistance have been broadly studied, the regulation of these mechanisms has not been completely understood. Accumulating evidence has recently highlighted the role of non-coding RNAs (ncRNAs), including long non-coding RNAs and microRNAs, in the development and maintenance of drug resistance due to their regulatory features in specific genes involved in the chemoresistant phenotype of GC. We review the literature on ncRNAs in drug resistance of GC. This review summarizes the current knowledge about the ncRNAs’ characteristics, their regulation of the genes involved in chemoresistance and their potential as targeted therapies for personalized treatment in resistant GC.

Comparison of totally laparoscopic total gastrectomy and laparoscopic-assisted total gastrectomy: A systematic review and meta-analysis

BACKGROUND

Laparoscopic-assisted total gastrectomy (LATG) has been extensively employed for the removal of gastric tumors, although it has several limitations. Totally laparoscopic total gastrectomy (TLTG) is a new technique that has rapidly been gaining popularity, and may help overcome the limitations of LATG; however, its safety and therapeutic effect remain controversial. In the present study, we aimed to assess the safety and efficacy of TLTG, and compare the short-term outcomes of TLTG and LATG.

METHODS

We searched for studies comparing TLTG and LATG published up to April 2018 from databases such as PubMed and Embase. The study results, including time of surgery, blood loss, anastomosis time, retrieved lymphatic nodes, proximal and distal resection edges, incision length, time to first fluid and soft diet, hospitalization duration, time to first flatus, and postsurgical and anastomotic complications, were compared between the procedures.

RESULTS

A total of 10 studies were included. TLTG led to reduced intraoperative blood loss (P < 0.01), greater number of retrieved lymphatic nodes (P < 0.01), decreased hospitalization duration (P < 0.01), reduced incision length (P = 0.05), and shorter time to first fluid diet (P < 0.05), as compared to LATG. The surgery and anastomosis times, time to first soft diet, resection edge, time to first flatus, overall postsurgical complications, and anastomosis-related complications were similar between TLTG and LATG (P > 0.05).

CONCLUSIONS

TLTG is a safe procedure that yields better cosmesis lower invasiveness, and faster recovery as compared to LATG.

The Cholegas trial: long-term results of prophylactic cholecystectomy during gastrectomy for cancer-a randomized-controlled trial

BACKGROUND

The incidence of cholelithiasis has been shown to be higher for patients after gastrectomy than for the general population, due to vagal branch damage and gastrointestinal reconstruction. The aim of this trial was to evaluate the need for routine concomitant prophylactic cholecystectomy (PC) during gastrectomy for cancer.

METHODS

A multicenter, randomized, controlled trial was conducted between November 2008 and March 2017. Of the total 130 included patients, 65 underwent PC and 65 underwent standard gastric surgery only for curable cancers. The primary endpoint was cholelithiasis-free survival after gastrectomy for gastric adenocarcinoma. Cholelithiasis was detected by ultrasound exam.

RESULTS

After a median follow-up of 62 months, eight patients (12.3%) in the control group developed biliary abnormalities (four cases of gallbladder calculi and four cases of biliary sludge), with only three (4.6%) being clinically relevant (two cholecystectomies needed, one acute pancreatitis). One patient in the PC group had asymptomatic biliary dilatation during sonography after surgery. The cholelithiasis-free survival did not show statistical significance between the two groups (P = 0.267). The number needed to treat with PC to avoid reoperation for cholelithiasis was 1:32.5.

CONCLUSIONS

Concomitant PC during gastric surgery for malignancies, although reducing the absolute number of biliary abnormalities, has no significant impact on the natural course of patients.

A remarkable clinical response in advanced gastric cancer treated with trastuzumab plus capecitabine combination chemotherapy: A report of two cases

When trastuzumab + capecitabine and cisplatin chemotherapy could not be conducted continuously because of severe adverse reactions to cisplatin, trastuzumab + capecitabine could be an alternative systemic chemotherapy options for metastatic or recurrent gastric cancer patients.

Down-regulated lncRNA SLC25A5-AS1 facilitates cell growth and inhibits apoptosis via miR-19a-3p/PTEN/PI3K/AKT signalling pathway in gastric cancer

Mounting evidence has illustrated the vital roles of long non-coding RNAs (lncRNAs in gastric cancer (GC). Nevertheless, the majority of their roles and mechanisms in GC are still largely unknown. In this study, we investigate the roles of lncRNA SLC25A5-AS1 on tumourigenesis and explore its potential mechanisms in GC. The results showed that the expressions of SLC25A5-AS1 in GC were significantly lower than that of adjacent normal tissues, which were significantly associated with tumour size, TNM stage and lymph node metastasis. Moreover, SLC25A5-AS1 could inhibit GC cell proliferation, induce G1/G1 cell cycle arrest and cell apoptosis in vitro, as well as GC growth in vivo. Dual-luciferase reporter assay confirmed the direct interaction between SLC25A5-AS1 and miR-19a-3p, rescue experiment showed that co-transfection miR-19a-3p mimics and pcDNA-SLC25A5-AS1 could partially restore the ability of GC cell proliferation and the inhibition of cell apoptosis. The mechanism analyses further found that SLC25A5-AS1 might act as a competing endogenous RNAs (ceRNA), which was involved in the derepression of PTEN expression, a target gene of miR-19a-3p, and regulate malignant phenotype via PI3K/AKT signalling pathway in GC. Taken together, this study indicated that SLC25A5-AS1 was down-regulated in GC and functioned as a suppressor in the progression of GC. Moreover, it could act as a ceRNA to regulate cellular behaviours via miR-19a-3p/PTEN/PI3K/AKT signalling pathway. Thus, SLC25A5-AS1 might be served as a potential target for cancer therapeutics in GC.

LncRNA ZEB2-AS1 contributes to the tumorigenesis of gastric cancer via activating the Wnt/β-catenin pathway

Studies have shown that long noncoding RNA Zinc finger E-box-binding homeobox 2 antisense RNA 1 (ZEB2-AS1) is involved in the progression of lung cancer, bladder cancer, and hepatocellular carcinoma. However, its role in the pathogenesis of gastric cancer remains unknown. The Wnt/β-catenin pathway contributes to the development of gastric cancer. ZEB2-AS1 expression was firstly detected in the gastric carcinoma tissue samples as well as in gastric cancer cells. Knockdown of ZEB2-AS1 was performed by ZEB2-AS1-shRNA, and the viability, migration, invasion, and apoptosis of gastric cancer cells were determined by CCK-8, scratch assay, transwell, and flow cytometry, respectively. Furthermore, levels of Ki-67, PCNA, VEGF, MMP9, epithelial-mesenchymal transition (EMT) markers (E-cadherin, Vimentin and ZEB2), cleaved caspase 3/8/9 and PARP, active β-catenin, c-Myc, cyclinD1, and AXIN2 were assayed by Western blot or real-time PCR. Additionally, the role and mechanism of ZEB2-AS1 were confirmed in a xenograft nude mouse model. We found ZEB2-AS1 expression was increased in gastric carcinoma samples, and it was correlated with tumor progression. Also, its expression was elevated in gastric cancer cells. Knockdown of ZEB2-AS1 reduced the proliferation, migration, invasion, and EMT, but increased the apoptosis of gastric carcinoma cells. Furthermore, ZEB2-AS1 downregulation remarkably suppressed the expression of Ki-67, PCNA, VEGF and MMP9, and the activation of Wnt/β-catenin signaling, whereas elevated the levels of cleaved caspase 3/8/9 and PARP in gastric cancer cells. And ZEB2 overexpression reversed the effects of ZEB2-AS1 downregulation on the proliferation, EMT and inactivation of Wnt/β-catenin signaling. Additionally, ZEB2-AS1 knockdown inhibited tumor growth, Ki-67 staining, and the expression of VEGF, MMP9, active β-catenin, c-Myc, cyclinD1, and AXIN2 in mice. In conclusion, ZEB2-AS1 promotes the tumorigenesis of gastric carcinoma that is related to the upregulation of ZEB2 and the activation of the Wnt/β-catenin pathway.

T and N Staging of Gastric Cancer Using Dual-Source Computed Tomography

Aim

This study is aimed at comparing gastric cancer T and N staging between virtual monochromatic energy images and fusion images generated by dual-source computed tomography (DSCT) dual-energy mode data acquisition prospectively while measuring the iodine concentration of gastric cancer and lymph nodes at different T and N stages from iodine map retrospectively.

Methods

A total of 71 patients (50 males and 21 females; mean age: 59 ± 11 years) confirmed with gastric cancer by endoscopic biopsy with no neoadjuvant chemotherapy were enrolled for the CT examination before surgeries. The preoperative T and N staging results were compared between groups with pathological results as the gold standard. The iodine concentrations of the gastric lesions and LNs were measured on the iodine-based material decomposition images. All iodine concentration values were normalized against those in the abdominal aorta and defined as normalized iodine concentration (nIC) values. The short axis length of LNs and nIC values were statistically analyzed.

Results

Group A was better than group B for T3 and T4 staging. No statistically significant difference in the overall accuracies for N staging was found between groups. For the late arterial and delayed phases, T3 and T4 nIC values of the extraserosal adipose tissue showed statistically significant differences. The nIC values between N0 and Nm (N1-N3) showed statistically significant differences in the portal phase only.

Conclusions

T3 and T4 nIC values of the extraserosal adipose tissue showed statistically significant differences. Hence, dual-source CT may be helpful in the differential diagnosis between T3 and T4.

Laparoscopic versus open gastrectomy for advanced gastric cancer: A meta-analysis based on high-quality retrospective studies and clinical randomized trials

BACKGROUND

Additional studies comparing laparoscopic gastrectomy (LG) with open gastrectomy (OG) have been published, and the meta-analysis of this subject should be improved.

METHODS

Randomized controlled trials and high-quality retrospective studies, which compared LG and OG for advanced gastric cancer (AGC) treatment and were published in English and Chinese between January 2000 and February 2017, were selected through PubMed, EMBASE, and the Cochrane Library database by two reviewers independently. The Jadad Composite Scale and the Newcastle-Ottawa scale were used to evaluate the quality and risk of bias for all included studies. Operative outcomes, postoperative outcomes, postoperative morbidity, harvested lymph nodes and 5-year overall survival (OS) were considered as primary endpoints and were compared.

RESULTS

Fifteen studies including a total of 9337 cases (5000 in LG and 4337 in OG) were enrolled. LG showed longer operative time, less intraoperative blood loss, and quicker recovery after operations. Based on the subgroup analysis of the sample size, however, there was no difference in operative time between LG and OG. The number of harvested lymph nodes, 5-year OS, and postoperative morbidity were similar.

CONCLUSION

LG can be performed as an alternative to OG for AGC, with quicker postoperative recovery and comparable safety and efficacy.

A dose-escalation study of docetaxel, oxaliplatin, and S-1 (DOS) as a first-line therapy for patients with unresectable metastatic gastric cancer

PURPOSE

The aim of this study was to determine the recommended dose (RD) for a docetaxel/oxaliplatin/S-1 (DOS) regimen in patients with unresectable gastric cancer and to preliminarily evaluate its efficacy.

METHODS

Previously untreated patients with histologically proven unresectable metastatic gastric cancer were enrolled (n = 16). Docetaxel and oxaliplatin were administered intravenously on day 8 and S-1 was administered orally twice a day on days 1-14. Each cycle was repeated every 3 weeks. Dose-limiting toxicities (DLTs) were evaluated during the first treatment cycle. Three dose escalations of DOS were employed in this study: level 1 (50/100/80 mg/m²), level 2 (50/130/80 mg/m²), and level 3 (60/130/80 mg/m²).

RESULTS

According to the 3 + 3 dose-escalating schedule, we determined that the RD and maximum tolerated dose for this regimen were level 1 and level 2, respectively. The DLTs were grade 3 diarrhea and febrile neutropenia. The overall response rate was 78% (7/9) for patients with measurable lesions and consisted of two complete responses and five partial responses. Five patients underwent conversion surgery. The median follow-up time was 19 months with median survival time and progression-free survival being 19.6 months and 7.6 months, respectively.

CONCLUSIONS

The results from this study demonstrated the safety and tolerability of DOS in unresectable metastatic gastric cancer patients and revealed promising preliminary efficacy with a high conversion rate. A phase II trial of DOS regimen using the identified RD is ongoing.

Curative Effect of Digestive Tract Reconstruction After Radical Gastrectomy for Distal Gastric Cancer

OBJECTIVE

Short-term complications and long-term prognoses of three kinds of digestive tract reconstructions after radical gastrectomy for distal gastric cancer were compared.

MATERIALS AND METHODS

Patients who underwent radical gastrectomy for distal gastric cancer were divided into three groups according to the type of digestive tract reconstruction: Billroth I, Billroth II, and Roux-en-Y anastomosis. Clinicopathological characteristics, intraoperative conditions, short-term complications, and long-term prognoses were compared among the three groups.

RESULTS

There were no significant differences in the clinicopathological characteristics and postoperative complications among the three groups (P > .05). There was no significant difference in the operative times of the Billroth I and Billroth II anastomosis groups, but the operative times in both groups were shorter than the operative time in the Roux-en-Y anastomosis group (P < .05). The 5-year overall survival (OS) rate in the Billroth I, Billroth II, and Roux-en-Y anastomosis groups was 58.3%, 55.0%, and 62.2%, respectively, with no significant difference among the three groups. There was no significant difference in the OS rate according to the tumor node metastasis stage among the three groups (P > .05).

CONCLUSION

The postoperative complications and prognoses were similar in the different digestive tract reconstruction groups. Billroth I anastomosis is a simple surgical method that can be used for gastrointestinal reconstruction after distal gastrectomy.

Enhanced expression of the long non-coding RNA SNHG16 contributes to gastric cancer progression and metastasis

This paper aimed to probe into the expression of long non-coding RNA (lncRNA) SNHG16 in human gastric cancer (GC) and its potential tumor biological functions. The expression of lncRNA SNHG16 was detected in GC and adjacent tissues and GC cell lines using qRT-PCR. GC MGC-803 cells were transfected with siRNA of lncRNA SNHG16, as well as blank and negative control. A series of experiments including CCK-8, flow cytometry, transwell, and wound healing assay were adopted to evaluate the effects of lncRNA SNHG16 on cell growth and metastasis. Besides, the nude mouse xenograft tumor model was established to draw tumor growth curve and measure tumor volume during treatments. TUNEL staining was used to determine the apoptosis rate of tissues. The expression of lncRNA SNHG16 in GC tissue, significantly associated with invasion depth, lymph node metastasis, TNM stage and histological differentiation (all P< 0.05), was upregulated compared with adjacent tissues. Transfected with siRNA of lncRNA SNHG16 inhibited GC MGC-803 cell proliferation, and arrested cells in the G0/G1 phase, and then promoted apoptosis rate with reduced cell invasion and shortened migration distance. Additionally, the nude mice xenograft presented lower tumor growth rate and weight loss alongside elevated apoptosis rate of tumor tissues. LncRNA SNHG16 is highly expressed in GC, while suppression of SNHG16 expression can inhibit proliferation, weaken invasion and migration of GC cells, and enhance apoptosis, to be a novel target for GC clinical treatment.

Exosomal TRIM3 is a novel marker and therapy target for gastric cancer

Background

Exosomes are critically involved in cancer development and progression. The exosomal contents have been suggested as ideal cancer biomarkers. In this study, we investigated the expression of exosomal proteins in the serum of gastric cancer patients and their roles in gastric cancer.

Methods

The proteomic profile of exosomes from the serum of gastric cancer patients was detected by using LC-MS/MS. The expression of TRIM3 in exosomes from the serum of gastric cancer patients and healthy controls was assessed by ELISA and western blot. Immunohistochemistry was used to detect TRIM3 expression in gastric cancer tissues and their matching adjacent tissues. The growth and migration abilities of gastric cancer cells with TRIM3 overexpression or knockdown in vitro were evaluated by colony formation assay and transwell migration assay. The effects of TRIM3 overexpression or knockdown on gastric cancer growth and metastasis in vivo were investigated by using subcutaneous xenograft tumor and peritoneal metastasis mouse model. The effects of TRIM3-overexpressing exosomes on gastric cancer growth and metastasis in vitro and in vivo were also evaluated.

Results

We found that the expression levels of TRIM3 mRNA and protein were decreased in gastric cancer tissues compared to the matched control tissues. In addition, the levels of TRIM3 protein in the serum exosomes of gastric cancer patients were lower than that in healthy controls. We demonstrated that TRIM3 overexpression reduced while TRIM3 knockdown promoted the growth and metastasis of gastric cancer in vitro and in vivo through the regulation of stem cell factors and EMT regulators. Moreover, exosomes-mediated delivery of TRIM3 protein could suppress gastric cancer growth and metastasis in vitro and in vivo.

Conclusions

Taken together, our findings suggest that exosomal TRIM3 may serve as a biomarker for gastric cancer diagnosis and the delivery of TRIM3 by exosomes may provide a new avenue for gastric cancer therapy.

Electronic supplementary material

The online version of this article (10.1186/s13046-018-0825-0) contains supplementary material, which is available to authorized users.

The pseudogene-derived long non-coding RNA SFTA1P suppresses cell proliferation, migration, and invasion in gastric cancer

Pseudogenes were once regarded as transcriptionally inactive and without specific molecular function. However, current evidence shows that pseudogene-derived long non-coding RNAs (lncRNAs) may be crucial regulators of human cancer development, including gastric cancer (GC). In the present study, we report that a pseudogene-derived lncRNA named surfactant associated 1, pseudogene (SFTA1P), which is 693-nt long, was significantly down-regulated in GC tissues compared with that in the adjacent normal tissues. In addition, decreased SFTA1P expression was strongly correlated with advanced tumor lymph node metastasis (TNM) stage, larger tumor size, lymphatic metastasis, and poor prognosis of patients with GC. Moreover, gain-of-function experiments revealed that the overexpression of SFTA1P inhibits cell proliferation, migration, and invasion, thus verifying the tumor inhibitory role of SFTA1P in GC. Furthermore, we investigated the potential action mechanism of SFTA1P. Our results showed that down-regulation of SFTA1P may be associated with decreased TP53 expression. In summary, our work suggests that the pseudogene-derived lncRNA SFTA1P functions as a tumor suppressor in GC and thus may act as a potential diagnostic and therapeutic target of GC.

Robotic versus laparoscopic gastrectomy with D2 lymph node dissection for advanced gastric cancer: a propensity score-matched analysis

Background

Robotic gastrectomy (RG) is a new surgical method alternative for gastric cancer. However, few studies have evaluated the outcomes of RG for advanced gastric cancer (AGC). Thus, the aim of this study was to compare the short-and long-term outcomes of RG and laparoscopic gastrectomy (LG) with D2 lymph node dissection for AGC.

Patients and methods

We retrospectively evaluated 454 patients with AGC who underwent RG or LG with D2 lymph node dissection for AGC between August 2013 and March 2017. The short-and long-term outcomes were compared between the propensity score-matched groups.

Results

The RG group was associated with longer operation time, less intraoperative blood loss, and higher hospital cost. Additionally, there was a tendency favoring RG in terms of number of harvested lymph nodes, time to first flatus, time to first start diet, and postoperative hospital stay, although the differences were not statistically significant. The overall postoperative complication rate was 13.4% and 11.6% in the RG and LG groups, respectively, with no significant difference (P=0.686). The 3-year overall survival and recurrence rates of the RG and LG groups were also comparable (78.6% vs 74.1%, P=0.483; 18.8% vs 21.4%, P=0.617; respectively).

Conclusion

RG with D2 lymph node dissection is safe and feasible for AGC in terms of both short- and long-term outcomes. High-volume randomized controlled trials with sufficient follow-up are needed to confirm this rationale.

HOXB7 overexpression promotes cell proliferation and correlates with poor prognosis in gastric cancer patients by inducing expression of both AKT and MARKs

Increased expression of HOXB7 has been reported to correlate with the progression in many cancers. However, the specific mechanism by which it promotes the evolution of gastric cancer (GC) is poorly understood.In this study, we sought to investigate the role of HOXB7 in GC by assessing HOXB7 expression in patient tissue and its correlation to clinical characteristics. We found that GC tissues showed increased expression of HOXB7 and that the HOXB7 expression was significantly associated with Lauren classification, invasion depth, lymphatic metastasis and poor prognosis, and could serve as an independent prognostic factor. To further investigate the role of HOXB7 in GC, we generated stable GC cell lines and both over-expressed and knocked down HOXB7 expression. Over-expression of HOXB7 in GC cell lines enhanced cell proliferation, colony formation, migration and invasion ability, whereas the opposite trends were observed upon reduction of HOXB7 expression by knockdown. These findings were further supported by our in vivo studies which show that HOXB7 expression can affect the GC cells' subcutaneous growth and lung metastases. A Phospho-MAPK Array Kit was used to explore the possible mechanism of HOXB7-induced cell proliferation and invasion. We found that the AKT signaling pathway and the two members of the MAPK pathway, were involved in those promoting effects. In conclusion, our results showed that increased expression of HOXB7 might play an important role in promoting GC proliferation, migration and invasion by inducing both AKT and MAPK pathways, thus resulting in progression of, and poor prognosis in GC patients.

AURKA induces EMT by regulating histone modification through Wnt/β-catenin and PI3K/Akt signaling pathway in gastric cancer

Gastric cancer, a highly invasive and aggressive malignancy, is the third leading cause of death from cancer worldwide. Genetic association studies have successfully revealed several important genes consistently associated with gastric cancer to date. However, these robust gastric cancer-associated genes do not fully elucidate the mechanisms underlying the development and progression of the disease. In the present study, we performed an alternative approach, a gene expression-based genome-wide association study (eGWAS) across 13 independent microarray experiments (including 251 gastric cancer cases and 428 controls), to identify top candidates (p<0.00001). Additionally, we conducted gene ontology analysis, pathway analysis and network analysis and identified aurora kinase A (AURKA) as our candidate. We observed that MLN8237, which is a specific inhibitor of AURKA, decreased the β-catenin and the phosphorylation of Akt1 and GSK-3β, as well as blocked the Akt and Wnt signaling pathways. Furthermore, MLN8237 arrested the cells in the G2/M phase. The activity of Wnt and Akt signaling pathways affected the level of histone methylation significantly, and we supposed that MLN8237 affected the level of histone methylation through these two signaling pathways. Additionally, the treatment of MLN8237 influenced the level of H3K4 me1/2/3 and H3K27 me1/2/3. Chip data on cell lines suggested that MLN8237 increases the level of H3K27 me3 on the promoter of Twist and inhibits EMT (epithelial-mesenchymal transition). In summary, AURKA is a potential therapeutic target in gastric cancer and induces EMT through histone methylation.

Long Noncoding RNA LINC01234 Functions as a Competing Endogenous RNA to Regulate CBFB Expression by Sponging miR-204-5p in Gastric Cancer

Purpose: Long noncoding RNAs (lncRNAs) have emerged as important regulators in a variety of human diseases, including cancers. However, the overall biological roles and clinical significance of most lncRNAs in gastric carcinogenesis are not fully understood. We investigated the clinical significance, biological function, and mechanism of LINC01234 in gastric cancer.Experimental Design: First, we analyzed LINC01234 alterations in gastric cancerous and noncancerous tissues through an analysis of sequencing data obtained from The Cancer Genome Atlas. Next, we evaluated the effect of LINC01234 on the gastric cancer cell proliferation and apoptosis, and its regulation of miR-204-5p by acting as a competing endogenous RNA (ceRNA). The animal model was used to support the in vitro experimental findings.Results: We found that LINC01234 expression was significantly upregulated in gastric cancer tissues and was associated with larger tumor size, advanced TNM stage, lymph node metastasis, and shorter survival time. Furthermore, knockdown of LINC01234-induced apoptosis and growth arrest in vitro and inhibited tumorigenesis in mouse xenografts. Mechanistic investigations indicated that LINC01234 functioned as a ceRNA for miR-204-5p, thereby leading to the derepression of its endogenous target core-binding factor β (CBFB).Conclusions: LINC01234 is significantly overexpressed in gastric cancer, and LINC01234-miR-204-5p-CBFB axis plays a critical role in gastric cancer tumorigenesis. Our findings may provide a potential new target for gastric cancer diagnosis and therapy. Clin Cancer Res; 24(8); 2002-14. ©2018 AACR.

Long noncoding RNA‑ATB promotes cell proliferation, migration and invasion in gastric cancer

Long noncoding RNA (lncRNA)‑activated by transforming growth factor (TGF)-β (lncRNA-ATB) was recognized as an unfavorable prognostic factor in various cancers; however, its regulatory role in gastric cancer (GC) remains elusive. The present study aimed to measure lncRNA‑ATB expression in GC and to explore its involvement in GC progression. lncRNA‑ATB expression levels were measured in 40 pairs of GC tissues and their normal adjacent tissues, as well as in 5 GC cell lines and a normal gastric mucosal cell line by reverse transcription-quantitative polymerase chain reaction. Knockdown experiments were performed to explore the effect of lncRNA‑ATB on the cell proliferation, invasion and migration. The results demonstrated that lncRNA‑ATB expression levels in GC tissues and GC cell lines were significantly higher than in the adjacent normal tissues and normal gastric mucosal cells. Further analysis of the correlation between the clinicopathological features and lncRNA‑ATB expression indicated that higher expression of lncRNA‑ATB was correlated with increased invasion depth, more distant metastasis and advanced tumor‑node‑metastasis stage. In addition, downregulated lncRNA‑ATB expression suppressed cellular proliferation, invasion and migration of GC cells. In conclusion, these data suggested that lncRNA‑ATB may serve as a clinical outcome predictor and potential therapeutic target in GC.

Polish Consensus on Treatment of Gastric Cancer; update 2017

The "Polish Research on Gastric Cancer" project has been continued since 1986. The main aim of this project, which is a multicenter and interdisciplinary research, is enhancing the treatment results of gastric cancer patients by developing and promoting the use of optimal methods for diagnosis and treatment, both surgical as well as combined. One of the more important achievements of the project is the development and publication of a document named "Polish Consensus on Treatment of Patients with Gastric Cancer", whose first version was published in 1998. Following versions were updated adequately to changing trends in the proceedings in patients with gastric cancer. A scientific symposium on "Polish Consensus on Treatment of Gastric Cancer - update 2016" was held in 3-4 June 2016 in Cracow. During the symposium a panel session was held during which all authors publicly presented the Consensus assumptions to be discussed further. Moreover, the already mentioned session was preceded by a correspondence as well as a working meeting in order to consolidate the position. It has to be underlined that the directions and guidelines included in the Consensus are not the arbitrarily assumed rules of conduct in a legal aspect and as such every doctor/team of doctors is entitled to make different decisions as long as they are beneficial to a patient with gastric cancer. The Consensus discusses as follows: a) recommended qualifications (stage of advancement, pathological, lymph node topography and the extent of lymphadenectomy, division of cancer of the gastroesophageal junction), b) rules for diagnostics including recommendations regarding endoscopic examination and clinical evaluation of the advancement stage, c) recommendations regarding surgical treatment (extent of resection, extent of lymphadenectomy, tactics of proceedings in cancer of the gastroesophageal junction), d) recommendations regarding combined treatment with chemotherapy or radiotherapy, e) place of endoscopic and less invasive surgery in the treatment of gastric cancer. This publication is a summary of the arrangements made in the panel session during the abovementioned scientific symposium in Cracow in 2016.

Histone acetyltransferase p300/CBP inhibitor C646 blocks the survival and invasion pathways of gastric cancer cell lines

The histone acetyltransferases (HATs) adenovirus E1A-associated protein (p300) and CREB binding protein (CBP) serve as coactivators during a diverse assortment of cellular processes. In the present study, p300 and CBP were highly expressed in 5 gastric cancer (GC) cell lines (SGC‑7901, MKN45, MGC-803, BGC-823 and KATO III) compared with human normal gastric epithelial cell line (GES-1). C646, a selective inhibitor of p300 and CBP, inhibited cell viability and cell cycle and promoted cell apoptosis in all 5 GC cell lines. In addition, C646 suppressed the migration and invasion capability of the GC cell lines, except for the middle-differentiated SGC-7901 cell line. Furthermore, we detected the differential expression of corresponding oncogenic signalling molecules, such as c-Met, Akt, Bcl-2, Bax, cyclin D1, MMP7 and MMP9, in GC cells following C646 treatment. In conclusion, our results suggest that C646 inhibits the acetylation of histone H3 via inactivation of p300 and CBP, resulting in antineoplastic effects toward GC cells. Thus, the selective HAT inhibitor C646 could be a promising antitumour reagent for GC treatment.

Association between spectral computed tomography images and clinicopathological features in advanced gastric adenocarcinoma

To investigate the role of spectral computed tomography (CT)-generated iodine concentration (IC) in the evaluation of clinicopathological features of advanced gastric adenocarcinoma (AGC), 42 patients who underwent abdominal enhanced CT with spectral imaging mode were selected for the present study. The IC of the primary lesion in the arterial phase (IC_AP) and portal venous phase (IC_VP) was measured and the IC of the aorta was used for a normalized iodine concentration (nIC). Micro-vessel density (MVD) and lymphatic vessel density (LVD) were detected using immunohistochemical assays against cluster of differentiation 34 and D2-40, respectively. Other clinicopathological characteristics were also documented. The IC parameters were revealed to be significantly increased in the high-MVD group, particularly for the nIC_VP (P=0.002). Additionally, the nIC_AP revealed a significant difference (P=0.041) between the high- and low-LVD group. The nIC_AP and nIC_VP were increased in the poorly differentiated group compared with the moderately differentiated group (P=0.040 and P=0.011, respectively). The ICs and MVD demonstrated a statistically significant positive linear correlation. nIC_VP was able to be used to discriminate between the moderately and poorly differentiated carcinomas, with an area under the receiver operating characteristic curve of 0.759. However, IC demonstrated no correlation with serosal involvement, lymph node metastasis, LVD, and nodular or metastatic tumors. The results of the present study suggest that the nIC_VP value may serve as a non-invasive marker for the angiogenesis of, and the differentiations between, patients with AGC.

Current advances of long non-coding RNA highly upregulated in liver cancer in human tumors

Long non-coding RNAs (lncRNAs) are a group of non-coding RNAs (ncRNAs) >200 nucleotides in length that govern diverse biological processes. Recent evidence suggests that lncRNAs are involved in cancer cell proliferation, apoptosis, invasion, migration, and metastasis. Dysregulation of lncRNAs has been observed in various tumors, and lncRNAs act as oncogenes or tumor suppressors in these malignancies. It has been revealed that lncRNA highly upregulated in liver cancer (HULC) is tightly correlated with a number of cancers such as hepatocellular carcinoma, gastric cancer, colorectal cancer, osteosarcoma, and diffuse large B-cell lymphoma. Depletion of HULC suppressed cancer cell proliferation, migration, and invasion and induced apoptosis. Additionally, HULC may function as a diagnostic biomarker and prognostic indicator for some tumors. In this review, we summarize the current knowledge of the role of HULC in cancer progression and the clinical management of human cancers.

Successful conversion surgery for gastric cancer with multiple liver metastases treated after S-1 plus cisplatin combination chemotherapy: a case report

BACKGROUND

Gastric cancer with multiple liver metastases have poor prognosis. Recently, stage IV gastric cancer patients who respond well to systemic chemotherapy can be treated by gastrectomy. We herein report a case of advanced gastric cancer with liver metastases who was successfully downstaged by systemic chemotherapy and underwent conversion surgery.

CASE PRESENTATION

A 60-year-old male patient was diagnosed with gastric cancer with multiple liver metastases [cT3N3M1, stage IV]. After 18 courses of S-1 plus cisplatin combination chemotherapy (S-1 administered orally (80 mg/m2/day) twice a day for 21 consecutive days and cisplatin (60 mg/m2) infused on day 8), marked regression of liver metastasis was achieved, and we performed open total gastrectomy with D2 lymph node dissection. The patient was discharged from the hospital 10 days after the operation. Histopathological examination revealed no malignant cells in the lymph nodes [ypT1bN0M0, stage IA]. S-1 as the adjuvant chemotherapy was administered for 12 months, and the patient is alive without a recurrence for 33 months after surgery.

CONCLUSIONS

Conversion surgery may improve the poor prognosis of gastric cancer.

Conversion therapy for inoperable advanced gastric cancer patients by docetaxel, cisplatin, and S-1 (DCS) chemotherapy: a multi-institutional retrospective study

BACKGROUND

Conversion therapy is an option for unresectable metastatic gastric cancer when distant metastases are controlled by chemotherapy; however, the feasibility and efficacy remain unclear. This study aimed to assess the feasibility and efficacy of conversion therapy in patients with initially unresectable gastric cancer treated with docetaxel, cisplatin, and S-1 (DCS) chemotherapy by evaluating clinical outcomes.

METHODS

One hundred unresectable metastatic gastric cancer patients, enrolled in three DCS chemotherapy clinical trials, were retrospectively evaluated. The patients received oral S-1 (40 mg/m² b.i.d.) on days 1-14 and intravenous cisplatin (60 mg/m²) and docetaxel (50-60 mg/m²) on day 8 every 3 weeks. Conversion therapy was defined when the patients could undergo R0 resection post-DCS chemotherapy and were able to tolerate curative surgery.

RESULTS

Conversion therapy was achieved in 33/100 patients, with no perioperative mortality. Twenty-eight of the 33 patients (84.8 %) achieved R0 resection, and 78.8 % were defined as histological chemotherapeutic responders. The median overall survival (OS) of patients who underwent conversion therapy was 47.8 months (95 % CI 28.0-88.5 months). Patients who underwent R0 resection had significantly longer OS than those who underwent R1 and R2 resections (P = 0.0002). Of the patients with primarily unresectable metastases, 10 % lived >5 years. Among patients who underwent conversion therapy, multivariate analysis showed that the pathological response was a significant independent predictor for OS.

CONCLUSIONS

DCS safely induced a high conversion rate, with very high R0 and pathological response rates, and was associated with a good prognosis; these findings warrant further prospective investigations.

Long non-coding RNA MALAT1 drives gastric cancer progression by regulating HMGB2 modulating the miR-1297

Background

Emerging evidences have verified that long non-coding RNAs (lncRNAs) play important regulatory roles in the pathogenesis and progression of cancers. lncRNAs metastasis associated lung adenocarcinoma transcript 1 (MALAT1) have been found to be up-regulated in some human cancers. The main objective of this study was to investigate the expression level and biological function of MALAT1 in gastric cancer (GC).

Methods

Quantificational real-time polymerase chain reaction (qRT-PCR) was performed to detect the mRNA levels of MALAT1 in 78 paired gastric carcinoma tissues and adjacent normal tissues, and the associations of MALAT1 expression with the clinicopathological features were analyzed, and the prognosis of gastric carcinoma patients was evaluated. The HMGB2 mRNA and protein expressions were detected by qRT-PCR and western-blot analysis. Luciferase reporter assay was used to determine miR-1297 was a target of MALAT1.

Results

In this study, we demonstrated MALAT1 was up-regulation in GC tissues compared with adjacent normal tissues and higher MALAT1 expression was correlated with local invasion, lymph node metastasis and TNM stage. Patients with higher MALAT1 expression predicted a shorter survival and poor prognosis. Functionally, we revealed that MALAT1 promoted cells proliferation and invasion in GC. Mechanistically, our results demonstrated that MALAT1 was negatively correlation with miR-1297 and functioned as a molecular sponging miR-1297, antagonizing its ability to suppress HMGB2 expression.

Conclusions

Taken together, these results demonstrated that MALAT1/miR-1297/HMGB2 axis acted as critical regulator pathway in GC tumorigenesis and progression, which provided a novel therapeutic target for gastric cancer.

YEATS Domain Containing 4 Promotes Gastric Cancer Cell Proliferation and Mediates Tumor Progression via Activating the Wnt/β-Catenin Signaling Pathway

Increased expression of YEATS domain containing 4 (YEATS4) has been reported to have a correlation with progression in many types of cancer. However, the mechanism by which it promotes the development of gastric cancer (GC) is rarely reported. This study aimed to investigate the effect of YEATS4 on cell proliferation and tumor progression. The mRNA and protein expressions of YEATS4 in GC tissues and cell lines were analyzed. BGC-823 cells then overexpressed or silenced YEATS4 by transfection of different plasmids. The regulatory effect of YEATS on cell viability, colony formation, cell apoptosis, and tumor growth in vivo was evaluated. Finally, we explored the underlying regulatory mechanism of YEATS4 on the Wnt/β-catenin pathway. YEATS4 was highly expressed in GC tissues and cell lines. Furthermore, Kaplan-Meier survival analysis and qRT-PCR analysis showed that the increased expression of YEATS4 indicated poor prognosis and tumor progression. The overexpression of YEATS4 significantly promoted cell proliferation and inhibited cell apoptosis, whereas the opposite trends were found upon the downregulation of YEATS4. Western blot analysis showed that the downregulation of YEATS4 inhibited protein expression and phosphorylation of β-catenin. In addition, decreased expressions of c-Myc, CDK6, CDK4, cyclin D1, and Bcl-2 and increased expression of Bax were observed in YEATS4 knockdown cells. Our results showed that increased expression of YEATS4 might play a critical role in promoting GC cell proliferation and apoptosis by activating the Wnt/β-catenin signaling pathway, indicating that the control of YEATS4 expression might be used as a promising therapy for GC.

The Impact of the Expression Level of Intratumoral Dihydropyrimidine Dehydrogenase on Chemotherapy Sensitivity and Survival of Patients in Gastric Cancer: A Meta-Analysis

The potential impact that the intratumoral expression level of dihydropyrimidine dehydrogenase (DPD) has on chemotherapy sensitivity and long-term survival for gastric cancer (GC) patients remains controversial; therefore, this study seeks to clarify this issue. Our meta-analysis was performed using Review Manager (RevMan) 5.3 software. In vitro drug sensitivity tests, correlation coefficients between sensitivity to 5-fluorouracil (5-FU), and expression levels of intratumoral DPD were used as effective indexes to analyse. Overall survival (OS) and progression-free survival (PFS) were used as endpoints for patient outcome, and hazard ratios (HRs) and 95% confidence intervals (CIs) were noted as measures of effect. There were 15 eligible studies including 1805 patients for the final analysis. The analysis revealed a statistically significant difference between the expression level of intratumoral DPD activity, DPD mRNA levels, and sensitivity to 5-FU in GC patients, with high expression levels of intratumoral DPD resulting in low sensitivity to 5-FU. However, no matter what therapeutic regimens were used, there was no significant difference for patient outcomes between high and low DPD expression groups, either in OS or in PFS. In conclusion, high levels of intratumoral DPD expression have a negative impact on sensitivity to 5-FU in GC patients, but no prognostic value for long-term survival was uncovered.

A Tumor-Specific Prognostic Long Non-Coding RNA Signature in Gastric Cancer

BACKGROUND Aberrant expression of long non-coding RNAs (lncRNAs) is associated with prognosis of gastric cancer, some of which could be further evaluated as potential biomarkers. In this study, we attempted to identify a specific lncRNA signature to predict the prognosis of gastric cancer. MATERIAL AND METHODS The genome-wide lncRNA expression in the high-throughput RNA-sequencing data was retrieved from the Cancer Genome Atlas (TCGA). Differential expression of lncRNAs was identified using the Limma package. Survival analysis was conducted by use of univariate and multivariate Cox regression models. Functional enrichment analysis of lncRNAs was based on co-expressed mRNAs. DAVID was used to perform gene ontology and KEGG pathway analysis. RESULTS A total of 452 differentially expressed lncRNAs between gastric cancer and matched normal tissues were screened, of which 76 lncRNAs were identified to be gastric cancer-specific from a pan-cancer analysis of 12 types of human cancer. Among these 76 gastric cancer-specific lncRNAs, 5 lncRNAs (CTD-2616J11.14, RP1-90G24.10, RP11-150O12.3, RP11-1149O23.2, and MLK7-AS1) were significantly associated with the overall survival of patients with gastric cancer. A gastric cancer-specific 5-lncRNA signature was deduced to divide the patients into high- and low-risk groups with significantly different survival times (P<0.0001). Multivariate Cox regression analysis showed that this 5-lncRNA signature was an independent predictor of prognosis. Functional enrichment analysis of the 5 lncRNAs showed that they were mainly involved in DNA replication, mitotic cell cycle, programmed cell death, and RNA splicing. CONCLUSIONS Our results suggest that this tumor-specific lncRNA signature may be clinically useful in the prediction of gastric cancer prognosis.

Long noncoding RNA HOXA-AS2 promotes gastric cancer proliferation by epigenetically silencing P21/PLK3/DDIT3 expression

Current evidence suggests that long noncoding RNAs (lncRNAs) may be an important class of functional regulators involved in human cancers development, including gastric cancer (GC). Here, we reported that HOXA cluster antisense RNA2 (HOXA-AS2), a 1048bp RNA, was upregulated in GC. Increased HOXA-AS2 expression in GC was associated with larger tumor size and higher clinical stage; patients with higher levels of HOXA-AS2 expression had a relatively poor prognosis. Further experiments revealed that HOXA-AS2 knockdown significantly inhibited GC cells proliferation by causing G1 arrest and promoting apoptosis, whereas HOXA-AS2 overexpression promoted cell growth. Furthermore, HOXA-AS2 could epigenetically repress the expression of P21, PLK3, and DDIT3 via binding with EZH2 (enhaner of zeste homolog 2), a key component of PRC2; ChIP assays demonstrated that EZH2 could directly bind to the promoter of P21, PLK3 and DDIT3, inducing H3K27 trimethylated. In conclusion, these data suggest that HOXA-AS2 could be an oncogene for GC partly through suppressing P21, PLK3, and DDIT3 expression; HOXA-AS2 may be served as a candidate prognostic biomarker and target for new therapies in human GC.

The pseudogene derived long noncoding RNA DUXAP8 promotes gastric cancer cell proliferation and migration via epigenetically silencing PLEKHO1 expression

Gastric cancer (GC) is the third leading cause of cancer death due to its poor prognosis and limited treatment options. Evidence indicates that pseudogene-derived long noncoding RNAs (lncRNAs) may be important players in human cancer progression, including GC. In this paper, we report that a newly discovered pseudogene-derived lncRNA named DUXAP8, a 2107-bp RNA, was remarkably upregulated in GC. Additionally, a higher level of DUXAP8 expression in GC was significantly associated with greater tumor size, advanced clinical stage, and lymphatic metastasis. Patients with a higher level of DUXAP8 expression had a relatively poor prognosis. Further experiments revealed that knockdown of DUXAP8 significantly inhibited cell proliferation and migration, as documented in the SGC7901 and BGC823 cell lines. Furthermore, RNA immunoprecipitation and chromatin immunoprecipitation assays demonstrated that DUXAP8 could epigenetically suppress the expression of PLEKHO1 by binding to EZH2 and SUZ12 (two key components of PRC2), thus promoting GC development. Taken together, our findings suggest that the pseudogene-derived lncRNA DUXAP8 promotes the progression of GC and is a potential therapeutic target for GC intervention.