The role of surgery in the treatment of gastric cancer

Predictive value of prognostic nutritional index in patients undergoing gastrectomy for gastric cancer: A systematic review and meta-analysis

BACKGROUND

The value of prognostic nutritional index (PNI) in gastrectomy remains controversial. This meta-analysis aimed to evaluate the predictive value of PNI in patients undergoing gastrectomy for malignancy.

METHODS

We retrieved studies from medical literature databases to analyze the endpoints of overall survival, cancer-specific survival, recurrence-free survival, and clinicopathologic features. The hazard ratio (HR) and 95% confidence interval (CI) were used to access the survival prognostic value of PNI in patients after gastrectomy. Odds ratio and mean difference were used to evaluate the relationship between the low PNI and clinicopathologic features.

RESULTS

In total, we included 38 articles (39 trial comparisons) which contained 23,756 gastrectomy patients. The results showed that low PNI was associated with shorter overall survival (HR: 1.82, 95% CI 1.62-2.03), shorter cancer-specific survival (HR: 1.44, 95% CI 1.24-1.67), and shorter recurrence-free survival (HR: 2.52, 95% CI 1.41-4.47). Besides, patients with low PNI had a higher risk of postoperative complications compared with high PNI (HR: 1.65, 95% CI 1.30-2.09). And low PNI group was found to be related to older, lower BMI, larger tumor size, deeper tumor invasion, poorer differentiation, more advanced tumor stage, total gastrectomy, and the presence of lymph node metastasis, lymphatic invasion, and vessel invasion.

CONCLUSION

PNI was significantly associated with survival and postoperative complications of gastric cancer patients undergoing gastrectomy. Therefore PNI has the potential to be a prognostic predictor for gastrectomy.

Linkers: An Assurance for Controlled Delivery of Antibody-Drug Conjugate

As one of the major therapeutic options for cancer treatment, chemotherapy has limited selectivity against cancer cells. Consequently, this therapeutic strategy offers a small therapeutic window with potentially high toxicity and thus limited efficacy of doses that can be tolerated by patients. Antibody-drug conjugates (ADCs) are an emerging class of anti-cancer therapeutic drugs that can deliver highly cytotoxic molecules directly to cancer cells. To date, twelve ADCs have received market approval, with several others in clinical stages. ADCs have become a powerful class of therapeutic agents in oncology and hematology. ADCs consist of recombinant monoclonal antibodies that are covalently bound to cytotoxic chemicals via synthetic linkers. The linker has a key role in ADC outcomes because its characteristics substantially impact the therapeutic index efficacy and pharmacokinetics of these drugs. Stable linkers and ADCs can maintain antibody concentration in blood circulation, and they do not release the cytotoxic drug before it reaches its target, thus resulting in minimum off-target effects. The linkers used in ADC development can be classified as cleavable and non-cleavable. The former, in turn, can be grouped into three types: hydrazone, disulfide, or peptide linkers. In this review, we highlight the various linkers used in ADC development and their design strategy, release mechanisms, and future perspectives.

Follow-Up Study Confirms the Presence of Gastric Cancer DNA Methylation Hallmarks in High-Risk Precursor Lesions

To adopt prevention strategies in gastric cancer, it is imperative to develop robust biomarkers with acceptable costs and feasibility in clinical practice to stratified populations according to risk scores. With this aim, we applied an unbiased genome-wide CpG methylation approach to a discovery cohort composed of gastric cancer (n = 24), and non-malignant precursor lesions (n = 64). Then, candidate-methylation approaches were performed in a validation cohort of precursor lesions obtained from an observational longitudinal study (n = 264), with a 12-year follow-up to identify repression or progression cases. H. pylori stratification and histology were considered to determine their influence on the methylation dynamics. As a result, we ascertained that intestinal metaplasia partially recapitulates patterns of aberrant methylation of intestinal type of gastric cancer, independently of the H. pylori status. Two epigenetically regulated genes in cancer, RPRM and ZNF793, consistently showed increased methylation in intestinal metaplasia with respect to earlier precursor lesions. In summary, our result supports the need to investigate the practical utilities of the quantification of DNA methylation in candidate genes as a marker for disease progression. In addition, the H. pylori-dependent methylation in intestinal metaplasia suggests that pharmacological treatments aimed at H. pylori eradication in the late stages of precursor lesions do not prevent epigenome reprogramming toward a cancer signature.

LINC01436 Inhibited miR-585-3p Expression and Upregulated MAPK1 Expression to Promote Gastric Cancer Progression

BACKGROUND

Gastric cancer (GC) is a prevalent type of digestion system malignancies. Dysregulation of long non-coding RNAs (lncRNAs) has been proven to be prognostic factors and biological regulators in human cancers.

AIMS

The current study aimed to explore the role of long intergenic non-protein coding RNA 1436 (LINC01436) and its underlying mechanism in the progression of GC.

METHODS

RT-qPCR was conducted to measure RNA expression. Western blot was used for exploration of protein level. CCK-8, caspase-3 activity, and transwell assays were applied to evaluate the proliferative, apoptotic, and migratory abilities of GC cells, respectively. Mechanical experiments were used to probe the molecular interplay between genes.

RESULTS

High LINC01436 level suggested low overall survival in GC patients, and LINC01436 was highly expressed in GC tissues and cells. Besides, LINC01436 knockdown hampered cell proliferation and migration, while facilitated cell apoptosis. Mechanistically, LINC01436 upregulated mitogen-activated protein kinase 1 (MAPK1) expression by competitively binding with miR-585-3p and inhibiting miR-585-3p expression. Furthermore, LINC01436 negatively regulated miR-585-3p expression by enhancing the zeste 2 polycomb repressive complex 2 subunit (EZH2)-induced trimethylation of histone H3 at lysine 27 (H3K27me3) on miR-585-3p promoter. Final rescue assays revealed that overexpression of MAPK1 could rescue the suppressive influence of LINC01436 depletion on GC progression.

CONCLUSIONS

LINC01436 epigenetically silences miR-585-3p and acts as miR-585-3p to upregulate MAPK1 expression and promote GC progression.

sMicroRNA-28-5p acts as a metastasis suppressor in gastric cancer by targeting Nrf2

The transcription factor nuclear factor (erythroid-2)-related factor 2 (Nrf2) can principally serve a mode of protection for both the normal cells and cancer cells from cellular stress, and elevates cancer cell survival. microRNA-28 (miR-28) has been involved in the regulation of Nrf2 expression in breast epithelial cells. However, no comprehensive analysis has been conducted regarding the function of miR-28-5p regulating Nrf2 in gastric cancer (GC). In this study, we aimed to evaluate their interaction and biological roles in the migration and invasion of GC cells. The expression of Nrf2 in the cancer tissues harvested from 42 patients with GC was examined by an array of molecular techniques comprising of Immunohistochemical staining, RT-qPCR and Western blot analysis. Kaplan-Meier method was adopted for analysis of the correlation of Nrf2 with the prognosis of GC patients. Interaction between miR-28-5p and Nrf2 was determined using the bioinformatics analysis and dual luciferase reporter gene assay. Gain- and loss-of-function studies of miR-28-5p and Nrf2 were conducted to elucidate their effects on GC cell migration, invasion and metastasis, as well as expression pattern of several epithelial-mesenchymal transition (EMT)-related proteins. Results indicated that the expression pattern of Nrf2 was significantly upregulated in GC tissues and indicative of poor prognosis of GC patients. miR-28-5p was verified to target Nrf2 and downregulate its expression. GC cells with overexpression of miR-28-5p or Nrf2 knockdown exhibited a marked reduction in the migrated and invasive abilities, along with the N-cadherin expression yet an increase of E-cadherin expression. Furthermore, miR-28-5p exerted an inhibitory function on the metastatic and tumorigenicity of GC cells. In conclusion, miR-28-5p is a comprehensive tumor suppressor that inhibits GC cell migration and invasion through repressing the Nrf2 expression. Therefore, miR-28-5p may serve as a potential biomarker for the prognosis of GC and a novel therapeutic target in advanced GC.

LncRNA SDHAP1 confers paclitaxel resistance of ovarian cancer by regulating EIF4G2 expression via miR-4465

Ovarian cancer has ranked as one of the leading causes of female morbidity and mortality around the world, which affects ∼239,000 patients and causes 152,000 deaths every year. Chemotherapeutic resistance of ovarian cancer remains a devastating actuality in clinic. The aberrant upregulation of long non-coding RNA succinate dehydrogenase complex flavoprotein subunit A pseudogene 1 (lncRNA SDHAP1) in the Paclitaxel (PTX)-resistant ovarian cancer cell lines has been reported. However, studies focussed on SDHAP1 in its regulatory function of chemotherapeutic resistance in ovarian cancer are limited, and the detailed mechanisms remain unclear. In this study, we demonstrated that SDHAP1 was upregulated in PTX-resistant SKOV3 and Hey-8 ovarian cancer cell lines while the level of miR-4465 was downregulated. Knocking-down SDHAP1 induced re-acquirement of chemo-sensitivity to PTX in ovarian cancer cells in vitro. Mechanically, SDHAP1 upregulated the expression of EIF4G2 by sponging miR-4465 and thus facilitated the PTX-induced apoptosis in ovarian cancer cells. The regulation network involving SDHAP1, miR-4465 and EIF4G2 could be a potential therapy target for the PTX-resistant ovarian cancer.

MiR-124-5p Inhibits the Progression of Gastric Cancer by Targeting MIEN1

Objective:

To observe the effect of miR-124-5p on progression of gastric cancer (GC) and explore the targeting mechanism.

Methods:

After collecting the specimens, we used real-time fluorescence quantitative PCR to detect the miR-124-5p level of GC tissue and corresponding adjacent tissue. Then MTT test and scratch wound-healing assay were hired to evaluate the influence of miR-124-5p in GC cell (SGC-803 and SGC7901) migration and proliferation ability. The binding of miR-124-5p to migration and invasion enhancer 1 (MIEN1) was detected through dual luciferase reporter gene experiment and western blot was utilized to assay the protein level of MIEN1.

Results:

Compared with adjacent tissues, miR-124-5p level in GC tissues was lower significantly. MiR-124-5p mimic inhibited the metastasis and proliferation ability of SGC7901 cells and miR-124-5p inhibitor promoted the migration and proliferation ability of SGC803 cells. In addition, miR-124-5p targeted MIEN1 and negatively modulated the MIEN1 expression in SGC-803 and SGC7901 cells. Silencing MIEN1 negatively regulated the metastasis and proliferation ability of SGC7901 cells.

Conclusion:

MiR-124-5p inhibited the GC cell proliferation and metastasis phenotypes through MIEN1, which probably becomes a novel molecular target for clinical GC treatment.

Optimal tumor coverage with different beam energies by IMRT, VMAT and TOMO: Effects on patients with proximal gastric cancer

To compare the effects of different photon energies on radiation planning by intensity-modulated radiotherapy (IMRT), volumetric-modulated arc therapy (VMAT) and helical tomotherapy (TOMO) for proximal gastric cancer (PGC). Network analysis with microarray procession and gene ontology were used to identify the effect of radiotherapy (RT) on PGC. Then, we retrospectively analyzed 8 PGC patients after receiving irradiation with a prescribed dose of 50.4 Gy. The Pinnacle treatment planning system (TPS, V9.8) was used to generate IMRT and VMAT plans by using 6 or 10 MV. TOMO plans were calculated on the Tomotherapy Planning Station Hi-Art Version 4.2.3 workstation (Tomotherapy Incorporated, Madison, WI, USA). PGC is associated with high DNA repair ability. TOMO plan results in higher tumor coverage and a better conformity index than IMRT and VMAT. 10-MV VMAT yields better dosimetric quality of the gradient index than 6-MV VMAT (P = .012). TOMO was associated with a lower irradiation dose in the mean dose to the right kidney (P = .049), left kidney and heart than 6-MV IMRT and 6-MV VMAT. 6-MV IMRT plan presented a higher dose of lung Dmean (P = .017) than 10-MV IMRT. Additionally, VMAT, using a planning energy of 6 MV, was associated with a significantly higher left kidney Dmean (P = .018) and V10 (P = .036) than a planning energy of 10 MV. TOMO is a better RT plan not only for tumor coverage but also for sparing organs at risk. IMRT and VMAT plans with 10 MV beams are more suitable than 6 MV beams for PGC treatment.

LncRNA-HNF1A-AS1 functions as a competing endogenous RNA to activate PI3K/AKT signalling pathway by sponging miR-30b-3p in gastric cancer

BACKGROUND

Accumulating evidence demonstrated that long noncoding RNAs (lncRNAs) played important regulatory roles in many cancer types. However, the role of lncRNAs in gastric cancer (GC) progression remains unclear.

METHODS

RT-qPCR assay was performed to detect the expression of HNF1A-AS1 in gastric cancer tissues and the non-tumourous gastric mucosa. Overexpression and RNA interference approaches were used to investigate the effects of HNF1A-AS1 on GC cells. Insight into competitive endogenous RNA (ceRNA) mechanisms was gained via bioinformatics analysis, luciferase assays and an RNA-binding protein immunoprecipitation (RIP) assay, RNA-FISH co-localisation analysis combined with microRNA (miRNA)-pulldown assay.

RESULTS

This study displayed that revealed expression of HNF1A-AS1 was associated with positive lymph node metastasis in GC. Moreover, HNF1A-AS1 significantly promoted gastric cancer invasion, metastasis, angiogenesis and lymphangiogenesis in vitro and in vivo. In addition, HNF1A-AS1 was demonstrated to function as a ceRNA for miR-30b-3p. HNF1A-AS1 abolished the function of the miRNA-30b-3p and resulted in the derepression of its target, PIK3CD, which is a core oncogene involved in the progression of GC.

CONCLUSION

This study demonstrated that HNF1A-AS1 worked as a ceRNA and promoted PI3K/AKT signalling pathway-mediated GC metastasis by sponging miR-30b-3p, offering novel insights of the metastasis mechanism in GC.

miR-92b promotes gastric cancer growth by activating the DAB2IP-mediated PI3K/AKT signalling pathway

Objectives

miR‐92b has been reported to play critical roles in several carcinomas; however, our understanding of the mechanisms by which miR‐92b stimulates gastric cancer (GC) is incomplete. The aim of this study was to investigate the clinical significance and functional relevance of miR‐92b in GC.

Materials and methods

Expression of miR‐92b in GC and peritumoural tissues was determined using qRT‐PCR, in situ hybridization and bioinformatics. CCK‐8, colony formation and fluorescence‐activated cell sorting assays were utilized to explore the effect of miR‐92b on GC cells. A luciferase reporter assay and Western blotting were employed to verify miR‐92b targeting of DAB2IP. Furthermore, Western blotting was used to evaluate the levels of DAB2IP and PI3K/Akt signalling pathway‐related proteins.

Results

In this study, we found that miR‐92b was upregulated in GC tissues compared with peritumoural tissues. Overexpression of miR‐92b promoted cell proliferation, colony formation, and G₀/G₁ transition and decreased apoptosis. Our results indicated that miR‐92b repressed the expression of DAB2IP and that loss of DAB2IP activated the PI3K/AKT signalling pathway. Overexpression of DAB2IP rescued the effects of miR‐92b in GC cells. Finally, our results demonstrated a significant correlation between miR‐92b expression and DAB2IP expression in GC tissues.

Conclusions

Our results suggest that miR‐92b promotes GC cell proliferation by activating the DAB2IP‐mediated PI3K/AKT signalling pathway. The miR‐92b/DAB2IP/PI3K/AKT signalling axis may be a potential therapeutic target to prevent GC progression.

GHSR DNA hypermethylation is a new epigenetic biomarker for gastric adenocarcinoma and beyond

Aberrations of DNA methylation are early events in the development of tumors. In this study, we investigated the DNA methylation status of growth hormone secretagogue receptor (GHSR), a promising pan-cancer biomarker, in gastric cancer (GC). Initially, data sets from DNA methylation and gene expression studies available at Gene Expression Omnibus (GEO) were analyzed. Confirmation was done on primary tumor specimens and adjacent normal stomach tissue samples. Both analyses showed significant hypermethylation of GHSR. For further validation, The Cancer Genome Atlas data on stomach cancer was used. A receiver operating characteristic curve analysis yielded an area under the curve value of 0.85, corroborating its usefulness as a diagnostic marker. A genome-wide comethylation analysis revealed several correlated genes. CREB1 was found to act as an upstream regulator of this gene network. Furthermore, GHSR methylation was found to be a biomarker in several other tumor entities, namely cancers of the bladder, endometrium, esophagus, head and neck, liver, thyroid, kidney, and ovary. Our findings along with previous reports on other types of cancer suggest a high potential of GHSR gene methylation as a pan-cancer biomarker, which could be considered for liquid biopsy applications.

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.

GPX3 hypermethylation in gastric cancer and its prognostic value in patients aged over 60

AIM

This study investigated the association between GPX3 methylation and gastric cancer (GC), and explored its prognostic value in patients undergoing radical gastrectomy.

MATERIALS & METHODS

The methylation levels of tumor and paracancerous tissues were detected by quantitative methylation-specific PCR method.

RESULTS

GPX3 was hypermethylated in GC (p = 4E-4), and was specific for patients with lymphatic metastasis (+), tumor invasion depth >3 cm and patients with poor differentiation. Additionally, GPX3 hypermethylation predicts a tumor recurrence in patients aged >60 (p = 0.019). Data from The Cancer Genome Atlas (TCGA) further confirmed GPX3 hypermethylation (cg21504918: -0.08 vs -0.25, p = 0.001). Additionally, TCGA showed an inverse correlation between GPX3 methylation and expression (p = 7E-18, r = -0.427). Data analysis of Gene Expression Omnibus (GEO) database showed that 5-aza-2'-deoxycytidine demethylating agent increased GPX3 expression (fold-change >2.19, p = 0.001).

CONCLUSION

Our results indicated GPX3 hypermethylation in GC, and predicted a shorter tumor recurrence time in patients aged >60.

miR-618 Suppresses Metastasis in Gastric Cancer by Downregulating the Expression of TGF-β2

Recent studies have demonstrated that microRNAs regulate gene expression and are related to cancer progression. Increasing evidence shows that miR-618 plays an important role in a variety of tumors, including thyroid carcinomas, breast cancer and lymphoma cancer. However, no studies have examined the expression or function of miR-618 in gastric cancer (GC). In this study, we examined the effects and molecular mechanisms of miR-618 in GC. We compared the expression levels of miR-618 in 90 paired GC tissues and adjacent noncancerous tissues. Cell cycle, apoptosis and transwell assays were performed in GC cells with miR-618 mimic or inhibitor in vitro. We first used quantitative PCR(qPCR) to show that miR-618 expression levels were downregulated in GC tissues, which showed statistical significance. Next we used transwell assays to prove that miR-618 suppressed the invasion and migration capacity of GC cells. Furthermore, screening of the miRDB and Target Scan Human databases indicated TGF-β2 as a downstream target of miR-618. In further research, we identified TGF-β2 as a target gene of miR-618 by the luciferase reporter assay. Western blot analysis confirmed that TGF-β2 expression was inversely correlated with miR-618 expression. In situ hybridization showed that miR-618 expression level was downregulated in GC tissues. In conclusion, our findings suggest that miR-618 may function as a tumor suppressor in GC and suppresses metastasis in GC by negatively regulating the transcriptional level of TGF-β2. Anat Rec, 302:931-940, 2019. © 2019 Wiley Periodicals, Inc.

Abnormal expression of miR‑133a in patients with acute myocardial infarction following radical surgery for gastric cancer and the underlying mechanism

The present study aimed to investigate the expression of microRNA (miR)‑133a in patients with or without acute myocardial infarction (AMI) following radical surgery for gastric cancer, and to explore its underlying mechanisms. Blood samples were collected from patients with or without AMI in order to detect the expression levels of miR‑133a and endothelial injury markers. In addition, an AMI rat model was established. Reverse transcription‑quantitative polymerase chain reaction was used to detect the mRNA expression levels of miR‑133a and B‑cell lymphoma 2‑like 1 (Bcl2l1). In addition, an ELISA assay was used for endothelial injury marker analysis. To investigate the effects of miR‑133a on human umbilical vein endothelial cells (HUVECs), a miR‑133a inhibitor was used. Cell proliferation and apoptosis were subsequently detected using an MTT assay and flow cytometry. Western blot analysis was also conducted to detect Bcl2l1 protein expression. The results suggested that patients with AMI exhibited significantly increased expression of endothelial injury markers (von Willebrand factor, heart‑type fatty acid‑binding protein and cardiac troponin I) and miR‑133a in blood samples compared with patients without AMI. In addition, treatment with a miR‑133a mimic was able to upregulate the expression of endothelial injury markers in an AMI rat model, whereas treatment with a miR‑133a inhibitor had the opposite effect. Furthermore, cellular experiments indicated that a miR‑133a inhibitor could promote HUVEC proliferation and reduce cell apoptosis. The present results also confirmed that miR‑133a directly targets Bcl2l1 and negatively regulates Bcl2l1 expression. In conclusion, the results of the present study suggested that miR‑133a was involved in the endothelial injury process after AMI by targeting Bcl2l1.

miR-671-5p inhibits gastric cancer cell proliferation and promotes cell apoptosis by targeting URGCP

Various studies have demonstrated that microRNA (miRNA) serves an important role in the development of gastric cancer. However, the expression level, clinical significance and the biological function of miRNA in gastric cancer remain largely unknown. The present study investigated the exact roles of miR-671-5p in gastric cancer, confirmed its target and explored its mechanism. Initially, the low expression levels of miR-671-5p in gastric cancer cells were confirmed by reverse transcription-quantitative polymerase chain reaction. TargetScan and MiRanda databases were utilized to forecast the target genes of miR-671-5p, and the prediction was verified by dual-luciferase reporter assay and western blot analysis. Cell Counting Kit-8 was used for cell proliferation detection. An annexin V-fluorescein isothiocyanate kit was used for cell apoptosis determination. Western blot analysis was adopted to measure the protein expression levels in different groups. The results of the present study revealed that there were lower expression levels of miR-671-5p in gastric cancer cells than in normal gastric cells. Upregulator of cell proliferation (URGCP) is a direct target of miR-671-5p and it may be negatively regulated by miR-671-5p. miR-671-5p mimics induced reduction of MKN28 cell proliferation. miR-671-5p mimics caused upregulation of MKN28 cell apoptosis. In addition, western blotting results indicated that the ratio of B-cell lymphoma 2 (Bcl-2)/Bcl-2-associated X protein was significantly decreased in the miR-671-5p mimic group compared with the negative control group (P<0.01). These results suggested that miR-671-5p had a protective role in gastric cancer through inhibiting gastric cancer cell proliferation and promoting cell apoptosis by targeting URGCP. Therefore, miR-671-5p may be an effective therapeutic target for gastric cancer.

MicroRNA-370 inhibits the proliferation, invasion and EMT of gastric cancer cells by directly targeting PAQR4

It has been reported that PAQR4 (Progestin and AdipoQ Receptor 4) expression is closely associated with progression of many cancers and microRNA (miRNA) processing. However, the effects and its precise mechanisms of PAQR4 in gastric cancer (GC) have not been well clarified. Our study aimed to explore the interaction between PAQR4 and miR-370 in GC. In our study, we found that the miR-370 level was significantly down-regulated in GC tissues and cell lines, and the expression of PAQR4 was dramatically increased. Interestingly, the low miR-370 level was closely associated with up-regulated PAQR4 expression in GC tissues. Moreover, introduction of miR-370 dramatically suppressed proliferation, invasion and EMT of GC cells. Whereas, miR-370 knockdown increased the proliferation, invasion and EMT in GC cells. We demonstrated that miR-370 could directly target PAQR4 by using both bioinformatics analysis and luciferase reporter assay. In addition, PAQR4 silencing had the similar effects with miR-370 overexpression on GC cells. Overexpression of PAQR4 in GC cells partially reversed the inhibitory effects of miR-370 mimic. miR-370 inhibited cell proliferation, invasion and EMT of GC cells by directly down-regulating PAQR4 expression, and miR-370 targeting PAQR4 was responsible for inhibition of the proliferation, invasion and EMT of GC cells.

Down-regulation of lncRNA ADAMTS9-AS2 contributes to gastric cancer development via activation of PI3K/Akt pathway

OBJECTIVE

We aimed to investigate the role and regulatory mechanism of lncRNA ADAMTS9-AS2 in the development of gastric cancer.

MATERIALS AND METHODS

The expression of lncRNA ADAMTS9-AS2 in gastric cancer tissues and cells was detected. According to the expression level of ADAMTS9-AS2, survival analysis for patients with gastric cancer was performed. In addition, SGC-7901 cells were transfected with pc-ADAMTS9-AS2, si-ADAMTS9-AS2 and scramble RNA (control) to investigate the effects of ADAMTS9-AS2 on cell proliferation, migration, invasion and apoptosis. Besides, the expression levels of key molecules involved in PI3K/Akt pathway were detected.

RESULTS

Results showed that lncRNA ADAMTS9-AS2 was significantly down-regulated in gastric cancer tissues and cells. Decreased expression of lncRNA ADAMTS9-AS2 was associated with poor prognosis in patients with gastric cancer. In comparison with control group, the SGC-7901 cell viability and the number of colony, migrated or invaded SGC-7901 cells of pc-ADAMTS9-AS2 group were significantly decreased while markedly increased in si-ADAMTS9-AS2 group. The percentage of apoptotic SGC-7901 cells in pc-ADAMTS9-AS2 group was significantly increased, while significantly decreased in si-ADAMTS9-AS2 group. Additionally, the expressions of p-PI3K and p-Akt were significantly down-regulated in pc-ADAMTS9-AS2 group compared with control group, while up-regulated in si-ADAMTS9-AS2 group. Furthermore, compared with si-ADAMTS9-AS2 group, treatment of an PI3K inhibitor LY294002 markedly reversed the effects of suppression of ADAMTS9-AS2 alone on SGC-7901 cells by inhibiting cell viability, colony-forming ability, migration, invasion, and increasing apoptosis.

CONCLUSIONS

Our results indicate that overexpression of ADAMTS9-AS2 may inhibit gastric cancer cell proliferation, suppress cancer cell migration and invasion, and induce cell apoptosis. Activation of PI3K/Akt pathway may be a key regulatory mechanism of ADAMTS9-AS2 in gastric cancer.

Overexpression of MYC binding protein promotes invasion and migration in gastric cancer

Gastric cancer (GC) is the second leading cause of cancer-associated mortality worldwide. Although the mortality rate of patients with GC has improved, it remains a significant health issue. The MYC proto-oncogene protein serves key roles in cellular proliferation, differentiation, transformation and apoptosis. Previous studies have identified the abnormal expression of MYC-binding protein (MYCBP) during tumorigenesis in multiple types of cancer. Furthermore, evidence demonstrates that the abnormal expression of MYCBP contributes to the invasion and migration of human cancer types, including colon cancer and glioma; however, its influence on GC remains unclear. In the present study, the expression of MYCBP in GC cells and tissues was analyzed by reverse transcription-quantitative polymerase chain reaction. Additionally, GC cell lines were transfected with small interfering RNAs against MYCBP or lymphoid enhancer-binding factor 1 (LEF-1) and assessed by in vitro transwell migration and invasion assays. The results indicated that the expression of MYCBP in GC cells and tissues was markedly increased compared with a normal gastric epithelial cell line and adjacent normal gastric mucosal tissues, respectively. Furthermore, MYCBP downregulation notably inhibited the metastatic capacity of GC cells, and LEF-1 knockdown was found to downregulate the expression of MYCBP. On the basis of the findings of the present study, MYCBP may be a direct target of the β-catenin/LEF-1 pathway via binding LEF-1, and could potentially be used as a biomarker for the diagnosis and prognosis of GC.

Keratin17 Promotes Tumor Growth and is Associated with Poor Prognosis in Gastric Cancer

Krt17 is a 48kDa protein member of keratin family. Previous literatures have demonstrated Krt17 may play a promotive role in the progression of various malignancies. However, the exact function of Krt17 in the carcinogenesis and the progression of gastric cancer (GC) remains unknown. In the present study, the expression of Krt17 in 20 fresh GC and matched normal tissues were detected and Krt17 was found to be significantly increased in GC tissues compared to normal tissues. And then the immunochemistry was performed to investigate the Krt17 expression in 569 GC tissue specimens, we found that the expression of Krt17 was remarkably positively correlated with the tumor size (P < 0.01), depth of invasion (T) (P < 0.001), lymph node metastasis (N) (P < 0.001), tumor node metastasis (TNM) stage (P < 0.001) and vascular invasion (P < 0.05). High expression of Krt17 predicted a poor prognosis of GC patients. In addition, we showed silencing of Krt17 inhibited GC cell proliferation, migration and invasion, and induced cell apoptosis by altering Bcl2 family protein expression and cleaved caspase3 upregulation. Moreover, silencing of Krt17 led to cell cycle arrest at G1/S stage by decreasing cyclin E1 and cyclin D expression. In conclusion, our findings revealed Krt17 can be used as a novel predictive biomarker, thus providing a novel therapeutic target for GC patients.

Expression of miR-195 is associated with chemotherapy sensitivity of cisplatin and clinical prognosis in gastric cancer

Gastric cancer has higher morbidity and mortality than other cancers for the low diagnosis rate and few therapies. MiR-195 has been reported to be involved in the occurrence, development and prognosis of various cancers. However, the function of miR-195 in gastric cancer remains largely unknown. Herein, the aims of this study were to probe the functional mechanism of miR-195 and its chemotherapy sensitivity as well as clinical prognosis in gastric cancer. We screened out low-expressed miR-195 through microarray analysis and further confirmed miR-195 was widely down-regulated in gastric cancer cells. Subsequently, AKT3 was identified as the direct target gene of miR-195 by target gene prediction software, dual luciferase reporter assay and western blot. Functional assays indicated that miR-195 acted as a tumor suppressor through regulating the proliferative, migrated and invasive properties of gastric cancer cells in vitro, and intratumoral delivery of miR-195 significantly suppressed tumor growth in vivo. Additionally, we also found miR-195 overexpression could enhance the chemotherapy sensitivity of cisplatin in gastric cancer cells and prolong the overall survival and progression free survival of gastric cancer patients. Collectively, our findings demonstrate miR-195 may be of great significance on early diagnosis of gastric cancer, providing the theoretical basis for prognosis and recurrence risk.

NFATc3 mediates the sensitivity of gastric cancer cells to arsenic sulfide

Arsenic sulfide (As4S4) is the main component of Realgar which is widely used in traditional Chinese medicine. Previously we showed that As4S4 inhibited the proliferation of colon cancer cells through regulating nuclear factor of activated T cells (NFAT) pathway. Here we explore the role of NFAT in gastric cancer. We showed that As4S4 inhibited the expression of NFATc1, NFATc3, and NFATc4, and modulated the expression of NFATc2 accompanying with p53. The baseline expression of NFATc3 varied distinctly in gastric cancer cell lines (AGS, MGC803, MKN28, MKN45, and SGC7901) and the sensitivity of these cells to As4S4 was dissimilar, with AGS and MGC803 cells showing higher sensitivity while the SGC7901 cells relatively resistant. Interestingly, the sensitivity to As4S4 was correlated with the level of expression of NFATc3, and the cells relatively sensitivity just showing higher expression of NFATc3. Furthermore, NFATc3 expression was significantly higher in gastric cancer tissues compared with the adjacent normal tissues. Our data also showed that, NFATc3 promoted the proliferation of gastric cancer cells by regulating c-Myc. In conclusion, As4S4 inhibited the proliferation of gastric cancer cells through NFATc3/c-Myc pathway and the diverse sensitivity among different cell lines correlated with the expression level of NFATc3 indicating that NFATc3 may be a potential therapeutic target in gastric cancer.

Comparison of gastric-cancer radiotherapy performed with volumetric modulated arc therapy or single-field uniform-dose proton therapy

BACKGROUND

Proton-beam therapy of large abdominal cancers has been questioned due to the large variations in tissue density in the abdomen. The aim of this study was to evaluate the importance of these variations for the dose distributions produced in adjuvant radiotherapy of gastric cancer (GC), implemented with photon-based volumetric modulated arc therapy (VMAT) or with proton-beam single-field uniform-dose (SFUD) method.

MATERIAL AND METHODS

Eight GC patients were included in this study. For each patient, a VMAT- and an SFUD-plan were created. The prescription dose was 45 Gy (IsoE) given in 25 fractions. The plans were prepared on the original CT studies and the doses were thereafter recalculated on two modified CT studies (one with extra water filling and the other with expanded abdominal air-cavity volumes).

RESULTS

Compared to the original VMAT plans, the SFUD plans resulted in reduced median values for the V18 of the left kidney (26%), the liver mean dose (14.8 Gy (IsoE)) and the maximum dose given to the spinal cord (26.6 Gy (IsoE)). However, the PTV coverage decreased when the SFUD plans were recalculated on CT sets with extra air- (86%) and water-filling (87%). The added water filling only led to minor dosimetric changes for the OARs, but the extra air caused significant increases of the median values of V18 for the right and left kidneys (10% and 12%, respectively) and of V10 for the liver (12%). The density changes influenced the dose distributions in the VMAT plans to a minor extent.

CONCLUSIONS

SFUD was found to be superior to VMAT for the plans prepared on the original CT sets. However, SFUD was inferior to VMAT for the modified CT sets.

MicroRNA-940 promotes tumor cell invasion and metastasis by downregulating ZNF24 in gastric cancer

Growing evidence indicates that microRNA (miRNA) plays a vital role in progression and metastasis of gastric cancer (GC). However, the underlying mechanism of miRNA-mediated metastasis has not been fully understood. Recently, miRNA-940 (miR-940) was found to be overexpressed in GC, which correlated with malignant progression and poor survival. Mechanistically, we found that miR-940 promoted GC cell migration, invasion, and metastasis in vivo by directly and functionally repressing the expression of Zinc Finger Transcription Factor 24 (ZNF24). Importantly, upregulation of ZNF24 could re-inhibit miR-940-induced migration and invasion. Hence, we demonstrated the oncogenic role of miR-940 in GC, finding that miR-940 promoted GC progression by directly downregulating ZNF24 expression, and targeting miR-940 could serve as a novel strategy for future GC therapy.

MicroRNA-125b promotes invasion and metastasis of gastric cancer by targeting STARD13 and NEU1

MicroRNAs have been documented playing key roles in cancer development and progression. Here, we investigate the role of miR-125b in gastric cancer metastasis. We found that the expression of miR-125b was up-regulated in gastric cancer tissue specimens compared with their corresponding nontumorous tissues, and the up-regulated miR-125b level was significantly associated with TNM stage and lymph node-metastasis. Overexpression of miR-125b promoted gastric cancer cell migration and invasion in vitro and metastasis in vivo. STARD13 and NEU1 were identified as direct target genes of miR-125b by luciferase assays, and they were involved in the cell migration and invasion regulated by miR-125b in gastric cancer. Taken together, miR-125b functions as an oncogene in gastric cancer and represents a new potential therapeutic target for gastric cancer.

Gastric cancer: Current status of lymph node dissection

D2 procedure has been accepted in Far East as the standard treatment for both early (EGC) and advanced gastric cancer (AGC) for many decades. Recently EGC has been successfully treated with endoscopy by endoscopic mucosal resection or endoscopic submucosal dissection, when restricted or extended Gotoda's criteria can be applied and D1+ surgery is offered only to patients not fitted for less invasive treatment. Furthermore, two randomised controlled trials (RCTs) have been demonstrating the non inferiority of minimally invasive technique as compared to standard open surgery for the treatment of early cases and recently the feasibility of adequate D1+ dissection has been demonstrated also for the robot assisted technique. In case of AGC the debate on the extent of nodal dissection has been open for many decades. While D2 gastrectomy was performed as the standard procedure in eastern countries, mostly based on observational and retrospective studies, in the west the Medical Research Council (MRC), Dutch and Italian RCTs have been conducted to show a survival benefit of D2 over D1 with evidence based medicine. Unfortunately both the MRC and the Dutch trials failed to show a survival benefit after the D2 procedure, mostly due to the significant increase of postoperative morbidity and mortality, which was referred to splenopancreatectomy. Only 15 years after the conclusion of its accrual, the Dutch trial could report a significant decrease of recurrence after D2 procedure. Recently the long term survival analysis of the Italian RCT could demonstrate a benefit for patients with positive nodes treated with D2 gastrectomy without splenopancreatectomy. As nowadays also in western countries D2 procedure can be done safely with pancreas preserving technique and without preventive splenectomy, it has been suggested in several national guidelines as the recommended procedure for patients with AGC.

The cross talk between long, non-coding RNAs and microRNAs in gastric cancer

Gastric cancer is one of the most common malignant diseases and remains the second leading cause of cancer-related mortality worldwide. Although great effort has been made during the past decades to facilitate the early detection and treatment of gastric cancer, the prognosis is not yet satisfactory and the underlying molecular mechanisms of gastric cancer pathogenesis are not fully understood. Meanwhile, non-coding RNAs have been established as key players in regulating various biological and pathological processes, such as cell-cycle progression, chromatin remodeling, gene transcription, and posttranscriptional processing. Furthermore, numerous studies have also revealed a complicated interplay among different species of non-coding RNAs; therefore, the cross-regulation between long non-coding RNAs (lncRNAs) and microRNAs (miRNAs) has begun to emerge. This lncRNA-miRNA cross talk, which has attracted increasing attention in recent years, is involved in a great number of human diseases including gastric cancer. In this review, we summarize the latest research progress of the interactions between lncRNAs and miRNAs, highlighting their influences on the development and progression of gastric cancer to provide novel approaches for cancer diagnosis and treatment.

HOTAIR Promotes Proliferation, Migration, and Invasion of Ovarian Cancer SKOV3 Cells Through Regulating PIK3R3

BACKGROUND

The aim of this study was to determine the effect on proliferation, migration, and invasion after silencing HOTAIR in ovarian cancer SKOV3 cells, and to elucidate the potential mechanism.

MATERIAL/METHODS

We analyzed the mRNA expression level of HOTAIR and PIK3R3 in ovarian cancer SKOV3, OVCAR3, and A2780 cell lines. We analyzed the mRNA expression level of HOTAIR and PIK3R3 in ovarian SKOV3 after transection with miR-214 or miR-217. We analyzed the mRNA and protein expression level of PIK3R3 when silencing HOTAIR. We analyzed the expression of HOTAIR when silencing PIK3R3. We analyzed the proliferation, migration and invasion in ovarian cancer SKOV3 after silencing HOTAIR or PIK3R3.

RESULTS

The expression of HOTAIR and PIK3R3 in ovarian SKOV3 and OVCAR3 was increased compared with A2780 cells (P<0.05). The mRNA level of HOTAIR and PIK3R3 in ovarian cancer SKOV3 cells was decreased when transected with miR-214 or miR-217 compared to negative control (p<0.05). The mRNA and protein level of PIK3R3 was decreased when HOTAIR was silenced and the mRNA level of HOTAIR was decreased when PIK3R3 was silenced (p<0.05). The proliferation, migration and invasion was decreased in ovarian SKOV3 when HOTAIR or PIK3R3 was silenced (p<0.05).

CONCLUSIONS

HOTAIR can promote proliferation, migration, and invasion in ovarian SKOV3 cells as a competing endogenous RNA.

Frequent amplification of PTP1B is associated with poor survival of gastric cancer patients

The protein tyrosine phosphatase 1B (PTP1B), a non-transmembrane protein tyrosine phosphatase, has been implicated in gastric pathogenesis. Several lines of recent evidences have shown that PTP1B is highly amplified in breast and prostate cancers. The aim of this study was to investigate PTP1B amplification in gastric cancer and its association with poor prognosis of gastric cancer patients, and further determine the role of PTP1B in gastric tumorigenesis. Our data demonstrated that PTP1B was significantly up-regulated in gastric cancer tissues as compared with matched normal gastric tissues by using quantitative RT-PCR (qRT-PCR) assay. In addition, copy number analysis showed that PTP1B was amplified in 68/131 (51.9%) gastric cancer cases, whereas no amplification was found in the control subjects. Notably, PTP1B amplification was positively associated with its protein expression, and was significantly related to poor survival of gastric cancer patients. Knocking down PTP1B expression in gastric cancer cells significantly inhibited cell proliferation, colony formation, migration and invasion, and induced cell cycle arrested and apoptosis. Mechanically, PTP1B promotes gastric cancer cell proliferation, survival and invasiveness through modulating Src-related signaling pathways, such as Src/Ras/MAPK and Src/phosphatidylinositol-3-kinase (PI3K)/Akt pathways. Collectively, our data demonstrated frequent overexpression and amplification PTP1B in gastric cancer, and further determined the oncogenic role of PTP1B in gastric carcinogenesis. Importantly, PTP1B amplification predicts poor survival of gastric cancer patients.

The diagnosis value of promoter methylation of UCHL1 in the serum for progression of gastric cancer

BACKGROUND

Aberrant promoter methylation has been considered as a potential molecular marker for gastric cancer (GC). However, the role of methylation of FLNC, THBS1, and UCHL1 in the development and progression of GC has not been explored.

METHODS

The promoter methylation status of UCHL1, FLNC, THBS1, and DLEC1 was assessed by quantitative methylation-specific PCR (QMSP) in the serum of 82 GC patients, 46 chronic atrophic gastritis (CAG) subjects, and 40 healthy controls.

RESULTS

All four genes had significantly higher methylation levels in GC patients than in CAG and control subjects. However, only UCHL1 methylation was significantly correlated with the tumor stage and lymph node metastasis. While THBS1 methylation was altered in an age-dependent manner, FLNC methylation was correlated with differentiation and Helicobacter pylori infection. DLEC1 methylation was only associated with tumor size. Moreover, methylated UCHL1 with or without THBS1 in the serum was found to be significantly associated with a poor prognosis.

CONCLUSION

The promoter methylation degree of FLNC, THBS1, UCHL1, and DLEC1 in serum could tell the existence of GC and only UCHL1 in the serum was also associated with poor prognosis of GC.

Roles of DPY30 in the Proliferation and Motility of Gastric Cancer Cells

Various types of histone methylation have been associated with cancer progression. Depending on the methylation site in histone proteins, its effects on transcription are different. DPY30 is a common member of SET1/MLL histone H3K4 methyltransferase complexes. However, its expression and roles in gastric cancer have been poorly characterized. To determine whether DPY30 has pathophysiological roles in gastric cancer, its expression and roles were examined. Immunohistochemistry and real time PCR showed up-regulation of DPY30 expression in some gastric cancer cell lines and patients’ tissues. Its knockdown by siRNA decreased the proliferation, migration, and invasion of gastric cancer cells, whereas its overexpression showed the opposite effects. These results indicate that DPY30 has critical roles in the proliferation, migration, and invasion of gastric cancer cells, and suggest DPY30 might be a therapeutic target in gastric cancer.

HOTAIR Interacting with MAPK1 Regulates Ovarian Cancer skov3 Cell Proliferation, Migration, and Invasion

Background

The aim of this study was to evaluate the effect of when silencing HOTAIR in ovarian cancer skov3 cells on proliferation, migration, and invasion, and to elucidate the mechanism by which this occurs.

Material/Methods

We detected the mRNA level of HOTAIR (HOX antisense intergenic RNA) and MAPK1 (mitogen-activated protein kinase 1) in ovarian cancer SKOV3, ES-2, OVCAR3, A2780, and COC1 cell lines. We detected the mRNA level of HOTAIR and MAPK1 in ovarian SKOV3 when transected with miR-1, miR-214-3p, or miR-330-5p. We detected the mRNA and protein level of MAPK1 when silencing HOTAIR. We detected the expression of HOTAIR when silencing MAPK1. Then we detected the proliferation, migration, and invasion in ovarian cancer skov3 after silencing HOTAIR or MAPK1.

Results

The expression of HOTAIR and MAPK1 in ovarian SKOV3, ES-2, and OVCAR3 increased compared with A2780 and COC1 cells (P<0.05). The mRNA level of HOTAIR and MAPK1 in ovarian SKOV3 decreased when transected with miR-1, miR-214-3p, or miR-330-5p compared to negative control (p<0.05). The mRNA and protein level of MAPK1 was decreased when silencing HOTAIR and the mRNA level of HOTAIR was decreased when silencing MAPK1 (p<0.05). The proliferation, migration, and invasion was inhibited in ovarian SKOV3 after silencing HOTAIR or MAPK1 (p<0.05).

Conclusions

HOTAIR can promote proliferation, migration, and invasion in ovarian SKOV3 cells as a competing endogenous RNA.

Increased expression of MMP14 correlates with the poor prognosis of Chinese patients with gastric cancer

The role of matrix metalloproteinase 14 (MMP14) has been identified to involve tumor progression and prognosis. The purpose of this study is to investigate the role of MMP14 in tumor progression and prognosis of gastric cancer. This study indicated that MMP14 mRNA and protein were overexpressed in gastric cancer tissue (P<0.001 and P=0.037, respectively) and significantly associated with clinical stage (P=0.005), lymph node metastasis (P=0.003), and distant metastasis (P=0.017). Moreover, we found that the overexpression of MMP14 was a significant predictor of poor prognosis for gastric cancer patients (P<0.001). Furthermore, we performed a meta-analysis which included 594 cases from 3 studies and showed that MMP14 overexpression was a significantly poor prognostic factor in Chinese patients with gastric cancer and HR (95% CI) was 2.17 (1.64-2.86). In conclusion, MMP14 plays an important role on gastric cancer progression and prognosis and acts as a convictive biomarker for prognostic prediction for Chinese patients with gastric cancer.

HOTAIR Long Noncoding RNA Promotes Gastric Cancer Metastasis through Suppression of Poly r(C)-Binding Protein (PCBP) 1

The objective of this study was to evaluate the role of HOTAIR long noncoding RNA in gastric cancer metastasis. We analyzed HOTAIR expression levels by real-time reverse transcription PCR and Northern blot analysis in 100 gastric tissues (50 gastric cancer tissues and 50 adjacent normal mucosa), and in four gastric cancer cell lines. Transient RNAi-mediated knockdown and pcDNA-mediated overexpression of HOTAIR were performed. Stable shRNA-mediated knockdown and lentiviral-mediated overexpression of HOTAIR were to study the role of HOTAIR on in vivo tumorigenicity and metastatic burden in the context of xenograft assays. Proteomic profiling was performed to decipher differential protein expression in cells with different HOTAIR expression levels. One of the differentially regulated proteins, Poly r(C)-binding protein (PCBP) 1, was subsequently validated and its function evaluated through xenograft assays. Expression of HOTAIR was significantly higher in cancerous tissues than in adjacent normal mucosa. HOTAIR expression levels dictated in vitro and in vivo tumorigenicity and metastatic potential in these cells. PCBP1 and HOTAIR have an inverse relationship, both at expression level and in function. A direct interaction between the two was confirmed through RNA immunoprecipitation coupled with quantitative real-time PCR. PCBP1 was confirmed to be an inhibitor of gastric cancer pathogenesis and as functionally opposite to HOTAIR long noncoding RNA. In conclusion, HOTAIR expression may serve as a potentially important disease biomarker for the identification of high-risk gastric cancer patients. Moreover, our findings provide mechanistic evidence for HOTAIR overexpression and PCBP1 downregulation and the ensuing malignant phenotype in both cultured and xenograft gastric cancer cells.

Pathogenetic mechanisms in gastric cancer

Gastric cancer (GC) is a major public health issue as the fourth most common cancer and the second leading cause of cancer-related death. Recent advances have improved our understanding of its molecular pathogenesis, as best exemplified by elucidating the fundamental role of several major signaling pathways and related molecular derangements. Central to these mechanisms are the genetic and epigenetic alterations in these signaling pathways, such as gene mutations, copy number variants, aberrant gene methylation and histone modification, nucleosome positioning, and microRNAs. Some of these genetic/epigenetic alterations represent effective diagnostic and prognostic biomarkers and therapeutic targets for GC. This information has now opened unprecedented opportunities for better understanding of the molecular mechanisms of gastric carcinogenesis and the development of novel therapeutic strategies for this cancer. The pathogenetic mechanisms of GC are the focus of this review.

Problems faced by evidence-based medicine in evaluating lymphadenectomy for gastric cancer

Gastric cancer surgical management differs between Eastern Asia and Western countries. Extended lymphadenectomy (D2) is the standard of care in Japan and South Korea since decades, while the majority of United States patients receive at most a limited lymphadenectomy (D1). United States and Northern Europe are considered the scientific leaders in medicine and evidence-based procedures are the cornerstone of their clinical practice. However, surgeons in Eastern Asia are more experienced, as there are more new cases of gastric cancer in Japan (107898 in 2012) than in the entire European Union (81592), or in South Korea (31269) than in the entire United States (21155). For quite a long time evidence-based medicine (EBM) did not solve the question whether D2 improves long-term prognosis with respect to D1. Indeed, eastern surgeons were reluctant to perform D1 even in the frame of a clinical trial, as their patients had a very good prognosis after D2. Evidence-based surgical indications provided by Western trials were questioned, as surgical procedures could not be properly standardized. In the present study we analyzed indications about the optimal extension of lymphadenectomy in gastric cancer according to current scientific literature (2008-2012) and surgical guidelines. We searched PubMed for papers using the key words “lymphadenectomy or D1 or D2” AND “gastric cancer” from 2008 to 2012. Moreover, we reviewed national guidelines for gastric cancer management. The support to D2 lymphadenectomy increased progressively from 2008 to 2012: since 2010 papers supporting D2 have achieved a higher overall impact factor than the other papers. Till 2011, D2 was the procedure of choice according to experts’ opinion, while three meta-analyses found no survival advantage after D2 with respect to D1. In 2012-2013, however, two meta-analyses reported that D2 improves prognosis with respect to D1. D2 lymphadenectomy was proposed as the standard of care for advanced gastric cancer by Japanese National Guidelines since 1981 and was adopted as the standard procedure by the Italian Research Group for Gastric Cancer since the Nineties. D2 is now indicated as the standard of surgical treatment with curative intent by the German, British and ESMO-ESSO-ESTRO guidelines. At variance American NCCN guidelines recommend a D1⁺ or a modified D2 lymph node dissection. In conclusion, D2 lymphadenectomy, originally developed by Eastern surgeons, is now becoming the procedure of choice also in the West. In gastric cancer surgery EBM is lagging behind national guidelines, rather than preceding and orienting them. To eliminate this lag, EBM should value to a larger extent Eastern Asian literature and should evaluate not only the quality of the study design but also the quality of surgical procedures.

Meta-analysis of pylorus-preserving gastrectomy for middle-third early gastric cancer

BACKGROUND

Pylorus-preserving gastrectomy (PPG) has been performed to reduce postprandial symptoms for some early gastric cancer (EGC) cases. The aim of this study was to evaluate the possible advantages after PPG for middle-third EGC in comparison with distal gastrectomy.

MATERIALS AND METHODS

We searched Medline, Embase, and Science Citation Index Expanded for relevant studies. Statistical analyses were conducted to calculate the summary weighted mean differences (WMDs) and odds ratios (ORs) with corresponding 95% confidence intervals (95% CIs) using random-effects models.

RESULTS

We identified 15 nonrandomized controlled trials (16 studies) with 1774 patients, which consisted of 11 studies for conventional PPG (CPPG) versus conventional distal gastrectomy (CDG) and 5 studies for laparoscopy-assisted PPG (LAPPG) versus laparoscopy-assisted distal gastrectomy (LADG). Meta-analysis of CPPG versus CDG revealed that CPPG had the advantage of prevention of early dumping syndrome (OR=0.18; 95% CI 0.12, 0.27), gastritis (OR=0.19; 95% CI 0.07, 0.53), duodenal juice reflux (OR=0.20; 95% CI 0.06, 0.66), and regaining of weight (WMD=3.53; 95% CI 2.34, 4.72). However, the incidence of gastric stasis was higher in the CPPG group than in the CDG group (OR=1.70; 95% CI 1.13, 2.57). Meta-analysis of LAPPG versus LADG revealed that LAPPG shortened the operation time (WMD=-21.12; 95% CI -31.33, -10.90) and did not increase the occurrence of postoperative complication (OR=0.72; 95% CI 0.41, 1.27).

CONCLUSIONS

With the benefits of prevention of early dumping syndrome, duodenal juice reflux, gastritis, and regaining of weight, PPG can be an excellent option for middle-third EGC.

The role of miR-148a in gastric cancer

PURPOSE

Gastric cancer is one of the most common malignant diseases worldwide, although much progress has been achieved in recent years, the early diagnosis and treatment for gastric cancer are not yet satisfactory and, thus the prognosis is still poor. MicroRNAs (miRNAs) can regulate a variety of physiological and developmental processes, it has been revealed that many miRNAs contribute the initiation and progression of various cancers. MiR-148a is one of the most important miRNAs in gastric cancer, and the aim of this paper is to provide an overview of various roles of miR-148a in gastric cancer.

METHODS AND RESULTS

We searched studies in electronic databases. MiR-148a was down-regulated in gastric cancer tissues and cell lines, which was resulted from the hypermethylation in its promoter region. Furthermore, miR-148a could regulate several different target genes and pathways involving tumor proliferation, invasion and metastasis.

CONCLUSION

MiR-148a may serve as a novel biomarker for the diagnosis and as a new therapeutic target in gastric cancer.

Detection of aberrant promoter methylation of RNF180, DAPK1 and SFRP2 in plasma DNA of patients with gastric cancer

Gastric cancer (GC) is one of the most frequently diagnosed malignancies in East Asia, particularly in China, and remains the second leading cause of cancer-associated mortality worldwide. However, no effective plasma biomarkers have been identified for the diagnosis of patients with GC. The aim of this study was to investigate the DNA methylation status of the ring finger protein 180 (RNF180), secreted frizzled-related protein 2 (SFRP2) and death-associated protein kinase 1 (DAPK1) genes in the plasma samples of 57 GC patients and 42 control individuals with no malignant disease, and to evaluate the clinical utility of these makers. A significantly higher level of methylation was observed in the plasma DNA of GC patients when compared with that of controls for the three genes investigated (RNF180, 57.89% vs. 23.81%; DAPK1, 49.12% vs. 28.57%; and SFRP2, 71.93% vs. 42.86%). No association was identified between the DAPK1 or SFRP2 methylation level in the plasma DNA and the clinicopathological parameters of patients. Notably, RNF180 methylation was found to positively correlate with tumor size (P=0.018), histological type (P=0.025), TNM stage (P=0.002), lymph node metastasis (P=0.008) and distant metastasis (P=0.018). Overall, 50 cancer patients (87.72%) exhibited methylation of at least one of the three markers, while 26 normal subjects presented methylation in plasma DNA [specificity, 38.1%; odds ratio (OR), 4.4]. The combined use of RNF180 and SFRP2 as methylation markers appeared to be the most preferable predictor with regard to predictive power and cost-performance (OR, 5.57; P=0.0002). The results of the present study indicate that aberrant promoter methylation of genes in the plasma may be detected in a substantial proportion of GC patients and thus, these genes must be evaluated in the screening and surveillance of GC.

miR-19a promotes cell growth and tumorigenesis through targeting SOCS1 in gastric cancer

Accumulating evidence has shown that microRNAs are involved in cancer development and progression. However, it remains unknown about the potential role of miR-19a in the pathogenesis of gastric cancer. Here, we report that suppressor of cytokine signaling 1 (SOCS1) is a novel target of miR-19a in gastric cancer cells and that miR-19a expression is inversely correlated with SOCS1 expression in gastric cancer cells and a subset of gastric cancer tissues. Ectopic expression of miR-19a dramatically promoted proliferation and tumorigenicity of gastric cancer cells both in vitro and in vivo. Moreover, we showed that silencing of SOCS1 promoted cell growth and colony formation resembling that of miR-19a overexpression, whereas re-introduction of SOCS1 (without the 3'-UTR) attenuated the pro-tumorigenic functions. Taken together, our findings suggest that the SOCS1 gene is a direct target of miR-19a, which functions as an oncogenic miRNA in gastric cancer by repressing the expression of tumor suppressor SOCS1.

Lnc RNA HOTAIR functions as a competing endogenous RNA to regulate HER2 expression by sponging miR-331-3p in gastric cancer

BACKGROUND

Accumulating evidence indicates that the long non-coding RNA HOTAIR plays a critical role in cancer progression and metastasis. However, the overall biological role and clinical significance of HOTAIR in gastric carcinogenesis remains largely unknown.

METHODS

HOTAIR expression was measured in 78 paired cancerous and noncancerous tissue samples by real-time PCR. The effects of HOTAIR on gastric cancer cells were studied by overexpression and RNA interference approaches in vitro and in vivo. Insights of the mechanism of competitive endogenous RNAs (ceRNAs) were gained from bioinformatic analysis, luciferase assays and RNA binding protein immunoprecipitation (RIP). The positive HOTAIR/HER2 interaction was identified and verified by immunohistochemistry assay and bivariate correlation analysis.

RESULTS

HOTAIR upregulation was associated with larger tumor size, advanced pathological stage and extensive metastasis, and also correlated with shorter overall survival of gastric cancer patients. Furthermore, HOTAIR overexpression promoted the proliferation, migration and invasion of gastric carcinoma cells, while HOTAIR depletion inhibited both cell invasion and cell viability, and induced growth arrest in vitro and in vivo. In particular, HOTAIR may act as a ceRNA, effectively becoming a sink for miR-331-3p, thereby modulating the derepression of HER2 and imposing an additional level of post-transcriptional regulation. Finally, the positive HOTAIR/HER2 correlation was significantly associated with advanced gastric cancers.

CONCLUSIONS

HOTAIR overexpression represents a biomarker of poor prognosis in gastric cancer, and may confer malignant phenotype to tumor cells. The ceRNA regulatory network involving HOTAIR and the positive interaction between HOTAIR and HER2 may contribute to a better understanding of gastric cancer pathogenesis and facilitate the development of lncRNA-directed diagnostics and therapeutics against this disease.

Preoperative S-1 and docetaxel combination chemotherapy in patients with locally advanced gastric cancer

PURPOSE

The combination of docetaxel and S-1 (DS) therapy is effective in patients with unresectable gastric cancer and is expected to be a regimen in neoadjuvant setting for advanced gastric cancer. This study was held to evaluate the efficacy and safety of DS followed by surgery.

METHODS

Patients with resectable gastric cancer received 2 courses of docetaxel 40 mg/m(2) on days 1, 15 and S-1 40 mg/m(2) bid orally on days 1-7, 15-21 every 4 weeks, followed by standard radical gastrectomy. Primary end point was the pathological response rate: rate of tumors in which one-third or more parts were affected.

RESULTS

Fourteen patients were enrolled. Thirteen (92.8 %) patients completed two courses of chemotherapy. Grade 3 adverse events were neutropenia in 3 (21.4 %) patients, anemia in 1 (6.2 %) patient and diarrhea in 1 (6.2 %) patient. There were no grade 4 adverse event and febrile neutropenia. All patients underwent R0 resection, and pathological response was found in 50.0 % of patients. There were no major surgical complications and no treatment-related mortality.

CONCLUSIONS

The neoadjuvant chemotherapy with DS was effective for patients with locally advanced gastric cancer with manageable toxicities. Further study to confirm the usefulness of this regimen is needed.

Post-surgical chemotherapy versus surgery alone for resectable gastric cancer

BACKGROUND

For gastric cancer surgery is the mainstay treatment. Chemotherapy seems to improve the survival results. But chemotherapy is not a complication-free therapy and its role has been questioned by some trials.

OBJECTIVES

To determine whether post-surgical chemotherapy should be used routinely in resectable gastric cancer.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) in The Cochrane Library, MEDLINE, EMBASE, and Science Citation Index Expanded (July 2013).

SELECTION CRITERIA

Randomised controlled trials (RCT) comparing post-surgical chemotherapy versus surgery alone for resectable gastric cancer.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed trials for inclusion and independently extracted the data. We analysed the data with both the fixed-effect and the random-effects models using the RevMan analysis software. We calculated the hazard ratio (HR) with 95% confidence interval (CI) based on intention-to-treat or available case analysis.

MAIN RESULTS

The authors identified 34 studies (7824 patients) reporting overall survival (OS) and only 15 reporting disease free survival (DFS) as well. Post-surgical chemotherapy showed an improvement in OS (HR 0.85; 95% CI 0.80 to 0.90) and an improvement in DFS (HR 0.79; 95% CI 0.72 to 0.87), although all the trials had a high risk of bias.The planned analysis of quality of life, return to work, and number of hospital admissions was impossible to complete as the outcome data for the analysis were not available from any trials.

AUTHORS' CONCLUSIONS

Post-surgical chemotherapy should be used routinely for resectable gastric cancer where possible. Further RCTs are needed to determine the role at each stage of disease.