Current Perspectives on Gastric Cancer

Application of da Vinci robot with the"3 + 2" mode in radical gastrectomy for gastric cancer

The aim of this study is to investigate the feasibility and advantages of the da Vinci robotic system with the "3 + 2" mode (3 robotic arms and 2 assistants) in radical gastrectomy for gastric cancer.The clinical data of 65 patients who underwent da Vinci robotic gastrectomy with the "3 + 2" mode from July 2016 to October 2019 were grouped into an observation group. An additional 65 patients who underwent robotic gastrectomy under the classic mode during the same period were grouped into a control group. The short-term surgical outcomes were compared between 2 different groups.Compared with the control group, the observation group had a significantly shorter operative time (176.18 ± 15.49 vs 203.85 ± 12.77 minutes, P < .001) and lower operation costs ($2761.19 ± $191.91 vs $3690.91 ± $162.82; P < .001). No statistical differences in other outcomes were observed (P > .05).We show that robotic gastrectomy with "3 + 2" mode is a safe and beneficial surgical procedure in new robotic surgery institutions.

Clinical significance and biological function of transcriptional repressor GATA binding 1 in gastric cancer: a study based on data mining, RT-qPCR, immunochemistry, and vitro experiment

Transcriptional repressor GATA binding 1 (TRPS1) is a newly discovered transcription factor, which has been reported in many tumors, except for gastric cancer (GC). In this study, we aimed to grope for clinical significance and biological function of TRPS1 in GC. TRPS1 expression in GC and its relationship with clinicopathological features were analyzed based on public databases, and verified by immunohistochemistry and RT-qPCR. Kaplan-Meier survival curve and Cox regression model were used to estimate the influence of TRPS1 on the univariate prognosis and multivariate survival risk factors of GC. The effects of TRPS1 on malignant biological behaviors of GC cells were studied by CCK8 cell proliferation, scratch test, and Transwell assay. The function of TRPS1 was further analyzed by signaling pathway analysis. TRPS1 mRNA expression in GC tissues was up-regulated and was of great significance in some prognostic factors. Protein expression of TRPS1 in tumor tissues was significantly higher than that in paracancerous tissues. Over-expression of TRPS1 was a poor prognostic indicator for GC patients. TRPS1 knockdown could inhibit the proliferation, migration, and invasion of GC cells. The important role of TRPS1 was in the extracellular matrix, and it was involved in actin binding and proteoglycan in cancer. The hub genes of TRPS1 (FN1, ITGB1) were defined. TRPS1 may be a tumor promoter and promote the development of GC by influencing the malignant biological behaviors of GC. TRPS1 is expected to be a key diagnostic and prognostic indicator for GC patients.

Identification of miR-135b as a novel regulator of TGFβ pathway in gastric cancer

Gastric cancer (GC) is a common malignant tumor worldwide, with a high incidence and low survival rate. The transforming growth factor-beta (TGFβ) signaling pathway usually plays a tumor-suppressive role and is normally quietened in GC. The downregulation of transforming growth factor-beta receptor II (TGFBR2) affects TGFβ signaling pathway, which exerts an immense effect on tumor cell proliferation and metastasis. Although the effect of the TGFβ signaling pathway on cancer cells is well studied, little is known about the mechanism by which TGFBR2 expression is downregulated. Here, we showed that TGFBR2 protein, but not TGFBR2 mRNA, was consistently downregulated in GC, suggesting that post-transcriptional mechanism is involved in the regulation of TGFBR2. Bioinformatics analysis and luciferase reporter analysis proved that miR-135b combines precisely with the 3'-UTR of TGFBR2 mRNA. EdU assays and cell migration assays respectively showed that miR-135b overexpression induced the growth and invasion of GC cells. However, the overexpression of TGFBR2 had the opposite effect. TGFBR2 acted as the direct target for miR-135b and was downregulated in gastric cancer cells. Therefore, miR-135b promotes proliferation and migration of GC cells by negatively regulating TGFBR2 expression, displaying an oncomiR effect. Altogether, this conclusive evidence supported that miR-135b mediates the progression of GC by targeting TGFBR2 and miR-135b/TGFBR2 axis can be used in future targeted therapy for GC.

Gastric carcinoma: Insights into risk factors, methods of diagnosis, possible lines of management, and the role of primary care

Gastric carcinoma represents the second most common type of malignancy that contributes to cancer-related mortality worldwide. However, the geographic incidence of gastric carcinoma had changed over the last few decades, possibly due to increased hygiene, increased awareness of the importance of healthy nutrition, and increased rates of eradication of Helicobacter pylori infection. Gastric carcinoma consists of two pathological variants, intestinal and diffuse. Early cases of gastric carcinoma may be asymptomatic. However, advanced cases may present with significant weight loss, dysphagia, abdominal pain, vomiting, and even severe upper gastrointestinal bleeding. Patients at high risk of developing gastric carcinoma should be adequately screened at primary healthcare centers for early detection and effective management. Lines of treatment vary according to the stage of the disease but surgical resection of the tumor with regional lymphadenectomy remains the gold standard of therapy. This review sheds light on gastric carcinoma given the recent trends regarding its prevalence, risk factors, types, clinical picture, methods of diagnosis, possible lines of management, and the role of primary care.

Total saponins from Lilium lancifolium: a promising alternative to inhibit the growth of gastric carcinoma cells

Bulbus Lilii, as a medicinal and edible plant, has anti-inflammatory, anti-oxidative and immunopotentiating pharmacological activities, which seems to be therapeutic on cancer prevention. The purpose of this study was to investigate the effects of total saponins from Lilium lancifolium (TSLL) on proliferation, apoptosis and migration of human gastric carcinoma cells lines SGC-7901 and HGC-27 and its underlying mechanism. The results showed that TSLL inhibited the proliferation of gastric carcinoma cells by suppressing the level of proliferating cell nuclear antigen (PCNA) and increased p21 level. TSLL induced cells apoptosis by up-regulating expression of pro-apoptotic protein Bax and down-regulating anti-apoptotic protein Bcl-2 expression. Meanwhile, TSLL remarkably inhibited cell migration and invasion, decreased matrix metalloproteinase-2 (MMP-2) expression and increased tissue inhibitor of metalloproteinases-1 (TIMP-1) expression. Notably, TSLL had stronger anti-cancer effect on undifferentiated HGC-27 cells than differentiated SGC-7901 cells. Accordingly, TSLL might be a promising candidate to prevent and suppress the growth of gastric carcinoma cells.

Redefinition of familial intestinal gastric cancer: clinical and genetic perspectives

BACKGROUND

Familial intestinal gastric cancer (FIGC) remains genetically unexplained and without testing/clinical criteria. Herein, we characterised the age of onset and disease spectrum of 50 FIGC families and searched for genetic causes potentially underlying a monogenic or an oligogenic/polygenic inheritance pattern.

METHODS

Normal and tumour DNA from 50 FIGC probands were sequenced using Illumina custom panels on MiSeq, and their respective germline and somatic landscapes were compared with corresponding landscapes from sporadic intestinal gastric cancer (SIGC) and hereditary diffuse gastric cancer cohorts.

RESULTS

The most prevalent phenotype in FIGC families was gastric cancer, detected in 138 of 208 patients (50 intestinal gastric cancer probands and 88 unknown gastric cancer histology relatives), followed by colorectal and breast cancers. After excluding benign and intronic variants lacking impact in splicing, 12 rare high-quality variants were found exclusively in 11 FIGC probands. Only two probands carried potentially deleterious variants, but lacked somatic second-hits, weakly supporting the monogenic hypothesis for FIGC. However, FIGC probands developed gastric cancer at least 10 years earlier and carried more TP53 germline common variants than SIGC (p=4.5E-03); FIGC and SIGC could be distinguished by specific germline and somatic variant profiles; there was an excess of FIGC tumours presenting microsatellite instability (38%); and FIGC tumours displayed significantly more somatic common variants than SIGC tumours (p=4.2E-06).

CONCLUSION

This study proposed the first data-driven testing criteria for FIGC families, and supported FIGC as a genetically determined, likely polygenic, gastric cancer-predisposing disease, with earlier onset and distinct from patients with SIGC at the germline and somatic levels.

Gastric cancer is associated with a high rate of microsatellite instability versus chronic gastritis: A retrospective study

Objective: Microsatellite instability (MSI) in gastric cancer contributes to genetic complexities of gastric cancer. In the current study, we employed a panel of mononucleotide and dinucleotide markers to detect MSI in 99 gastric cancer patients and 91 chronic gastritis patients and further analyzed the association of MSI with clinicopathologic variables of the study patients.

Methods: We retrospectively analyzed the clinicopathologic data of primary gastric cancer patients and chronic gastritis patients. MSI was analyzed using five microsatellite markers, including D2S12, D5S346, D17S799, BAT26, and D18S34. MSI was defined as either a band shift or the appearance of a novel band in DNA. Multivariate logistic regression analysis was used to predict risk of MSI.

Results: Seventeen (17.2%) gastric cancer patients and 7 (7.7%) chronic gastritis patients were positive for MSI (P=0.012). Multivariate analysis further showed that gastric cancer was associated with a significantly higher likelihood for MSI versus gastritis (OR 3.73; 95% CI 1.19, 11.72; P=0.024) while age, drinking or smoking was not associated with increased MSI.

Conclusion: Gastric cancer is associated with a high rate of MSI. MSI should be further explored in future studies with a larger sample size for its role in gastric cancer development and as a predictive biomarker.

Study on the mechanisms of compound Kushen injection for the treatment of gastric cancer based on network pharmacology

Background

As an effective prescription for gastric cancer (GC), Compound Kushen Injection (CKI) has been widely used even though few molecular mechanism analyses have been carried out.

Methods

In this study, we identified 16 active ingredients and 60 GC target proteins. Then, we established a compound-predicted target network and a GC target protein-protein interaction (PPI) network by Cytoscape 3.5.1 and systematically analyzed the potential targets of CKI for the treatment of GC. Finally, molecular docking was applied to verify the key targets. In addition, we analyzed the mechanism of action of the predicted targets by Kyoto Encyclopedia of Genes and Genomes (KEGG) and Gene Ontology (GO) analyses.

Results

The results showed that the potential targets, including CCND1, PIK3CA, AKT1, MAPK1, ERBB2, and MMP2, are the therapeutic targets of CKI for the treatment of GC. Functional enrichment analysis indicated that CKI has a therapeutic effect on GC by synergistically regulating some biological pathways, such as the cell cycle, pathways in cancer, the PI3K-AKT signaling pathway, the mTOR signaling pathway, and the FoxO signaling pathway. Moreover, molecular docking simulation indicated that the compounds had good binding activity to PIK3CA, AKT1, MAPK1, ERBB2, and MMP2 in vivo.

Conclusion

This research partially highlighted the molecular mechanism of CKI for the treatment of GC, which has great potential in the identification of the effective compounds in CKI and biomarkers to treat GC.

Inpatient burden of gastric cancer in the United States

Background

Gastric cancer is associated with significant morbidity and mortality. Over one-half of patients have advanced disease at the time of presentation, leading to a significant burden on the healthcare system. Limited epidemiological data exists on national inpatient hospitalization trends. The aim of this study is to determine the inpatient burden of gastric cancer in the United States.

Methods

We analyzed the Nationwide Inpatient Sample (NIS) database for all subjects with the diagnosis of malignant neoplasm of the stomach (ICD-9 code 151.x) as primary diagnosis during the period from 2001-2011. NIS is the largest all-payer inpatient care database in the U.S. Statistical significance of variation in the number of hospitalizations, patient demographics, and comorbidity measures was determined using Cochran-Armitage trend test.

Results

From 2001 to 2011, the number of hospitalizations with the diagnosis of malignant neoplasm of the stomach ranged between 22,430 and 25,371, however, the trend was not significant. Men were always more affected than women with no significant change in overall proportion (P<0.0001). Overall, in-hospital mortality decreased from 11.19% in 2001 to 6.47% in 2011 (P<0.0001). However, average cost of care per hospitalization increased from $21,710 in 2001 to $24,706 in 2011 (adjusted for inflation, P<0.0001).

Conclusions

The total number of hospitalizations remained relatively stable throughout the study period with higher proportion of men affected every year. Although in-hospital mortality in patients with the diagnosis of gastric cancer decreased over the study period, there was a significant rise in the cost of care.

Gastric cancer in autoimmune gastritis: A case-control study from the German centers of the staR project on gastric cancer research

Objectives

Patients with autoimmune gastritis (AIG) are reported to have an increased risk of developing gastric cancer (GC). In this study, we assess the characteristics and outcomes of GC patients with AIG in a multicenter case-control study.

Methods

Between April 2013 and May 2017, patients with GC, including cancers of the esophagogastric junction (EGJ) Siewert type II and III, were recruited. Patients with histological characteristics of AIG were identified and matched in a 1:2 fashion for age and gender to GC patients with no AIG. Presenting symptoms were documented using a self-administered questionnaire.

Results

Histological assessment of gastric mucosa was available for 572/759 GC patients. Overall, 28 (4.9%) of GC patients had AIG (67 ± 9 years, female-to-male ratio 1.3:1). In patients with AIG, GC was more likely to be localized in the proximal (i.e. EGJ, fundus, corpus) stomach (odds ratio (OR) 2.7, 95% confidence interval (CI) 1.0–7.1). In GC patients with AIG, pernicious anemia was the leading clinical sign (OR 22.0, 95% CI 2.6–187.2), and the most common indication for esophagogastroduodenoscopy (OR 29.0, 95% CI 7.2–116.4). GC patients with AIG were more likely to present without distant metastases (OR 6.2, 95% CI 1.3–28.8) and to be treated with curative intention (OR 3.0, 95% CI 1.0–9.0). The five-year survival rates with 95% CI in GC patients with and with no AIG were 84.7% (83.8–85.6) and 53.5% (50.9–56.1), respectively (OR 0.25, 95% CI 0.08–0.75, p = 0.001).

Conclusions

Pernicious anemia leads to earlier diagnosis of GC in AIG patients and contributes significantly to a better clinical outcome.

Index-based dietary patterns in relation to gastric cancer risk: a systematic review and meta-analysis

Dietary indices are widely used in diet quality measurement, and the index-based dietary patterns are related to gastric cancer risk. To evaluate the relationship between different kinds of index-based dietary patterns and gastric cancer risk, we systematically searched four English-language databases and four Chinese-language databases. The quality of studies was assessed by the Newcastle–Ottawa Scale. Meta-analyses were performed to estimate the association between gastric cancer incidence and different types of index-based dietary patterns. The OR and hazard ratios (HR) of gastric cancer incidence were calculated by regression models in case–control studies and prospective cohort studies, respectively. The studies were pooled in the random effects model to calculate the summarised risk estimate of the highest quantile interval of dietary indices, taking the lowest as the referent. The dietary indices included different versions of Mediterranean diet score (MDS) and dietary inflammatory index (DII), healthy eating index, Chinese Food Pagoda score and food index score. The meta-analysis was carried out for studies on MDS and DII. The combined OR of gastric cancer for the highest MDS v. the referent was 0·42 (95 % CI 0·2, 0·86), and the combined HR was 0·89 (95 % CI 0·68, 1·17). The combined OR for DII was 2·11 (95 % CI 1·41, 3·15). Higher Mediterranean dietary pattern consumption might reduce gastric cancer risk, while higher inflammatory diet pattern consumption might increase gastric cancer risk.

Adapting and Surviving: Intra and Extra-Cellular Remodeling in Drug-Resistant Gastric Cancer Cells

Despite the significant recent advances in clinical practice, gastric cancer (GC) represents a leading cause of cancer-related deaths in the world. In fact, occurrence of chemo-resistance still remains a daunting hindrance to effectiveness of the current approach to GC therapy. There is accumulating evidence that a plethora of cellular and molecular factors is implicated in drug-induced phenotypical switching of GC cells. Among them, epithelial-mesenchymal transition (EMT), autophagy, drug detoxification, DNA damage response and drug target alterations, have been reported as major determinants. Intriguingly, resistant GC phenotype may be the result of GC cell-induced tumor microenvironment (TME) remodeling, which is currently emerging as a key player in promoting drug resistance and overcoming cytotoxic effects of drugs. In this review, we discuss the possible mechanisms of drug resistance and their involvement in determining current GC therapies failure.

Utilizing gastric cancer organoids to assess tumor biology and personalize medicine

While the incidence and mortality of gastric cancer (GC) have declined due to public health programs, it remains the third deadliest cancer worldwide. For patients with early disease, innovative endoscopic and complex surgical techniques have improved survival. However, for patients with advanced disease, there are limited treatment options and survival remains poor. Therefore, there is an urgent need for more effective therapies. Since novel therapies require extensive preclinical testing prior to human trials, it is important to identify methods to expedite this process. Traditional cancer models are restricted by the inability to accurately recapitulate the primary human tumor, exorbitant costs, and the requirement for extended periods of development time. An emerging in vitro model to study human disease is the patient-derived organoid, which is a three-dimensional system created from fresh surgical or biopsy tissues of a patient’s gastric tumor. Organoids are cultured in plastic wells and suspended in a gelatinous matrix, providing a substrate for extension and growth in all dimensions. They are rapid-growing and highly representative of the molecular landscape, histology, and morphology of the various subtypes of GC. Organoids uniquely model tumor initiation and growth, including steps taken by normal stomach cells to transform into invasive, intestinal-type tumor cells. Additionally, they provide ample material for biobanking and screening novel therapies. Lastly, organoids are a promising model for personalized therapy and warrant further investigation in drug sensitivity studies for GC patients.

Expression of GCRG213p, LINE-1 endonuclease variant, significantly different in gastric complete and incomplete intestinal metaplasia

Background

Intestinal metaplasia (IM) of the gastric mucosa is classified as complete (Type I) and incomplete IM (Type II and III) subtypes, which showed significantly different risk for developing to gastric adenocarcinoma (GAC). GCRG213, a variant of L1-endonuclease (L1-EN), first identified in our lab, was upregulated in GAC tissue. However, the relationship between GCRG213 and IM subtypes is not clear. Our study explored the association of GCRG213 protein (GCRG213p) with IM subtypes.

Methods

Gastric cancer and/or para-tumor tissue samples were collected from 123 patients who underwent gastrectomy for intestinal type gastric adenocarcinoma. The subtypes of IM were characterized with Alcian blue-periodic acid-Schiff and High Iron Diamine-Alcian blue staining methods. Immunohistochemistry of GCRG213p was performed, and its expression in gastric adenocarcinoma and para-tumor tissue including dysplasia, IM, and normal mucosa were analyzed.

Results

GCRG213p was expressed in 48.94% IM, 57.14% dysplasia and 55.32% GAC, respectively. GCRG213p expression was higher in well and moderately differentiated adenocarcinoma (P = 0.037). In IM glands, GCRG213p expressed mainly in the cytoplasm of absorptive enterocytes with defined brush borders, but not in goblet cells. The expression of GCRG213p in type I IM (90.00%) was significantly higher than that in type II (36.36%) and type III (25.00%) (P < 0.001). In normal gastric mucosa, GCRG213p was exclusively positive in the cytoplasm of gastric chief cells.

Conclusions

The expression of GCRG213p in complete IM was significantly higher than in incomplete IM, which implies that GCRG213p may play a role on the developing of IM to adenocarcinoma. GCRG213p was exclusively expressed in chief cells, suggesting that it might be involved in cell differentiation from the chief cells to IM.

The effect of using simethicone with or without N-acetylcysteine before gastroscopy: A meta-analysis and systemic review

BACKGROUND/AIM

To assess the efficacy and safety of simethicone with or without N-acetylcysteine (NAC) as premedications before gastroscopy.

MATERIALS AND METHODS

We searched EMBASE, PubMed, Cochrane library and Web of Science database for randomized clinical controlled trials regarding simethicone ± NAC as oral drinking agents before gastroscopy. Statistical software RevMan5.3 was used for statistical analysis.

RESULTS

Ten randomized clinical trials that fulfilled the inclusion criteria were further pooled into a meta-analysis, which included 5,750 patients. The rate of positive findings in simethicone plus NAC group was higher than that in water group (risk ratio [RR] =1.31, 95%CI: 1.12-1.53, P = 0.0006) with high level of evidence. There was no significant difference on the rate of positive findings when comparing simethicone with simethicone plus NAC (RR = 1.02, 95%CI: 0.90-1.16, P = 0.71) and with water (RR = 1.13, 95%CI: 0.82-1.55, P = 0.46), respectively. Simethicone plus NAC showed better total mucosal visibility score than simethicone alone (MD = -0.14 (-0.25, -0.03), P = 0.01) without obvious heterogeneity. Both simethicone plus NAC and simethicone alone offer more benefit than water. The procedure time in simethicone group was shorter than that in water group (MD = -1.23 (-1.51, -0.96), P < 0.00001). Regarding adverse events, there was no significant difference in simethicone and water group (RR = 0.45, 95%CI: 0.2-1.0, P = 0.05, I² = 0%).

CONCLUSIONS

As premedication of gastroscopy, simethicone plus NAC offers more benefit on positive findings and total mucosal visibility score.

Interaction of H. pylori with toll-like receptor 2-196 to -174 ins/del polymorphism is associated with gastric cancer susceptibility in southern China

BACKGROUND

Genetic polymorphisms of Toll-like receptors play important roles in gastric carcinogenesis. The aim of this study was to determine the role of TLR2-196 to -174 ins/del polymorphism in gastric cancer susceptibility and prognosis.

METHODS

This study included 520 people from southern China. Samples were genotyped by the allele-specific polymerase chain reaction, among which 10% were randomly selected for sequencing. The serological method was used to determine Helicobacter pylori.

RESULTS

The TLR2 genotype was not associated with the risk of H. pylori infection. The del/del genotype exhibited significantly higher gastric cancer risk (adjusted OR 2.59, 95% CI 1.33‒5.07) than that of the ins/ins genotype. Further stratification analyses demonstrated that the del/del genotype was associated with a risk of intestinal gastric cancer (adjusted OR 2.62, 95% CI 1.34-5.14). In addition, the presence of the del/del genotype and the H. pylori infection conferred a synergistic effect (OR 3.04, 95% CI 1.33‒6.98) for the development of gastric cancer. The del/del genotype was not associated with a poor prognosis in gastric cancer patients.

CONCLUSION

The del/del genotype is associated with an increased gastric cancer risk in the southern Chinese population. However, TLR2 polymorphism is neither associated with H. pylori infection, nor with a poor prognosis.

APC gene is modulated by hsa-miR-135b-5p in both diffuse and intestinal gastric cancer subtypes

Background

Several genetic and epigenetic alterations are related to the development and progression of Gastric Cancer (GC), one of those being the deregulated microRNA (miRNA) expression profile. miRNAs are small noncoding RNAs that negatively regulate the expression of thousands of genes, including oncogenes and tumor suppressor genes. Our group identified, in previous studies, some miRNAs that are differentially expressed in GC when compared to the gastric mucosa without cancer, including hsa-miR-29c and hsa-miR-135b. The aim of the study was to modulate the expression of the miRNAs hsa-miR-29c-5p and hsa-miR-135b-5p and evaluate the expression of their target genes in 2D and 3D cell cultures.

Methods

hsa-miR-29c-5p and hsa-miR-135b-5p expression profiles were modulated by transfecting mimics and antimiRs, respectively, in 2D and 3D cell cultures. The expression of the proteins coded by the genes CDC42, DNMT3A (target genes of hsa-miR-29c-5p) and APC (target gene of hsa-miR-135b-5p) were measured by Western Blot.

Results

Results showed that mimics and antimiRs transfection significantly altered the expression of both miRNAs, increasing the expression of hsa-miR-29c-5p and reducing the expression of hsa-miR-135b-5p, especially in the 3D culture of the cell lines. When analyzing the proteins expression, we observed that AGP01 and AGP03 cell lines transfected with mimics had a reduction in the levels of CDC42 and DNMT3A and all three cell lines transfected with antimiRs had an increase in the expression of the protein APC.

Conclusion

We concluded that three-dimensional culture can be a more representative in vitro model that resembles better the in vivo reality. Our results also showed that hsa-miR-29c-5p is an important regulator of CDC42 and DNMT3A genes in the intestinal subtype gastric cancer and hsa-miR-135b-5p regulates the APC gene in both intestinal and diffuse subtypes of GC. Dysregulation in their expression, and consequently in their respectively signaling pathways, shows how these miRNAs can influence the carcinogenesis of different histological subtypes of gastric cancer.

Electronic supplementary material

The online version of this article (10.1186/s12885-018-4980-7) contains supplementary material, which is available to authorized users.

The SOX2OT/miR-194-5p axis regulates cell proliferation and mobility of gastric cancer through suppressing epithelial-mesenchymal transition

Recent studies reported that long noncoding RNAs (LncRNAs) were involved in tumorigenesis of various human cancer types, including gastric cancer (GC) through targeting microRNAs (miRNAs/miRs). The present study investigated the biological functions of LncRNA SOX2 overlapping transcript (SOX2OT)/miR-194-5p axis and its underlying mechanism in the tumor progression of GC. The results showed that relative expression of LncRNA SOX2OT was highly upregulated while the expression of miR-194-5p was down-regulated in GC tissues and cell lines (MGC-803, SGC-7901, MKN-74). Knockdown of SOX2OT inhibited cell proliferation, invasion and migration of GC cells (MGC803, MKN-74) through reducing epithelial-mesenchymal transition (EMT). Moreover, miR-194-5p was predicted to be one of the targets of SOX2OT through bioinformatics analysis and was verified by luciferase reporter assay. miR-194-5p expression was negatively regulated by SOX2OT expression in GC cells and miR-194-5p inhibitor was found to counteract the inhibitory effects of SOX2OT short hairpin (sh)RNA on cell proliferation and mobility through enhancing EMT in GC cells. Taken together, the in vitro experiments revealed that knockdown of SOX2OT inhibited cell proliferation and mobility through suppressing EMT via targeting miR-194-5p in GC. In addition, results from in vivo experiments showed that knockdown of SOX2OT suppressed GC tumor growth and matrix metalloproteinase (MMP)-2 and MMP-9 expression through inhibiting EMT. Besides that, relative expression of miR-194-5p was increased in sh-SOX2OT group compared with sh-NC group. In summary, our study elucidated that the SOX2OT/miR-194-5p axis participated in the tumor progression of GC through regulation of EMT both in vitro and in vivo. Hence, targeting the SOX2OT/miR-194-5p axis may aid in establishing novel strategies for therapy of GC.

The clinical significance of miR-335, miR-124, miR-218 and miR-484 downregulation in gastric cancer

Gastric cancer (GC) is one of the leading types of malignancy worldwide, particularly in Asian populations. Although the exact molecular mechanism of GC development remains unknown, microRNA (miRNA) has recently been shown to be involved. The current study aims to investigate the expression levels of bioinformatically ranked miRNAs in gastric tissues. Using bioinformatics tools, we prioritized miRNAs thought to be implicated in GC. Furthermore, polyA-qPCR was used to validate bioinformatics findings in 40 GC, 31 normal gastric tissue (NG) and 45 gastric dysplasia (GD) samples. As identified by bioinformatics analysis, miR-335 was shown to be the top-ranked miRNA implicated in GC. Moreover, a significant downregulation of miR-335, miR-124, miR-218 and miR-484 was found in GC and GD compared to NG samples. We found bioinformatics to be an efficient approach to finding candidate miRNAs relevant to GC development. Finally, the findings show that downregulation of miRNAs such as miR-124 and miR-218 in gastric tissue can be a significant indicator for neoplastic transformation.

Diagnostic and prognostic value of circulating lncRNA H19 in gastric cancer

Gastric cancer (GC) is among the most frequent malignant diseases. Despite advances in treatment, the clinical outcome of patients with GC remains poor. The establishment of novel biomarkers is urgently required for early detection, treatment evaluation and prognostic assessment. Non-coding RNAs (ncRNAs) are a key topic of intensive research due to their potential applications in the field of oncology. The long ncRNA H19 has been frequently reported as overexpressed in many cancers including GC. In the present study, the diagnostic and prognostic value of circulating H19 in GC was assessed. Higher levels of circulating H19 were identified in GC patients (n=40) compared with a control group consisting of endoscopy-verified GC-free individuals (n=42; median levels relative to GAPDH, 58.4 vs. 29.9; P=0.027). Patients with smaller tumor sizes (<5 cm) exhibited higher H19 in their circulation compared with those with larger tumors (≥5 cm; P=0.04). Plasma levels of H19 declined significantly upon surgical removal of gastric tumors as documented in a subset of patients [n=20; relative median levels, 146.0 vs. 15.0 (pre-surgery); P=0.003]. However, it was identified that H19 had no prognostic role in GC by the Kaplan-Meier method. In conclusion, the present findings identify H19 as potential diagnostic marker in GC.

Pathogenic roles of alterations in vitamin D and vitamin D receptor in gastric tumorigenesis

Gastric cancer is currently the second leading cause of cancer-related death worldwide, especially in Japan, Korea and China, and the 5-year survival rate of gastric cancer is less than 30%. Thus, it is important to shed more lights on novel agents to prevent gastric cancer or to improve survival rate of the patients. Vitamin D not only maintains calcium and bone homeostasis, but also mostly inhibits tumor genesis, invasion, and metastasis through activation of vitamin D receptor. Although epidemiological results are not consistent, accumulating evidence from gastric cancer cells, animal models, and clinical trials suggest that vitamin D deficiency may increase the risk and mortality of gastric cancer, but vitamin D supplement might be a safe and economical way to prevent or treat gastric cancer. Here, we reviewed the current studies on vitamin D and its receptor and focused on the pathogenic roles of their alterations in gastric tumorigenesis.

Distinct molecular subtypes of gastric cancer: from Laurén to molecular pathology

In Western countries the majority of gastric cancers (GC) are usually diagnosed in advanced stages reporting a 5-year survival rate of only 26%. The Laurén classification of GC was most widely used in clinical practice since it reflects GC morphology, epidemiology, tumor biology, clinical management and outcome. Despite the initial promise of individualizing antitumor treatment, the management of GC still remains relatively broad and general. Apart from clinical staging, molecular profiling enables targeting of the identified underlying alterations, rather than histology. In contrast to breast carcinoma, molecular classification of GC does not yet imply treatment modality. Molecular classifications of GC and their therapeutic implications are therefore extensively studied. The current proposed molecular divisions of GC come from three different parts of the world where different standard treatment modalities for advanced GC are recommended. Wider use of GC molecular subtyping may solve problems, such as susceptibility to novel systemic therapy regimens or selection of patients for aggressive surgery and targeted adjuvant/conversion therapy. In any case, the rapid entry of novel molecular targeted therapies into routine oncology practice clearly underscores the urgent need for clinicians to be aware of these new possibilities.

Diagnosis and treatment of early gastric cancer: experience of one center

Introduction

Gastric cancer is one of the most common malignant neoplasms in the world. Currently it constitutes the third cause of death among all malignancies. New endoscopic techniques have a potential to improve treatment results due to more frequent detection of early gastric cancer.

Aim

To summarize our experience in diagnosis and treatment of early gastric cancer patients.

Material and methods

We analyzed the results of endoscopic examination, histopathological findings and treatment methods in 16 patients who were diagnosed with early gastric cancer in the Endoscopy Unit of the Oncology Center in Bydgoszcz between 2014 and 2016.

Results

Between 2014 and 2016 sixteen patients, 12 (75.0%) male and 4 (25.0%) female, were diagnosed with early gastric cancer. The average age of patients was 65.5 years. Surgery qualification concerned mainly G2 and G3 adenocarcinomas. In 12 (75.0%) patients total gastrectomy was performed, and 1 patient underwent wedge resection of the prepyloric part of the stomach. In 3 cases endoscopic submucosal dissection (ESD) was performed. Histopathological examination of both biopsy and postoperative material indicated 8 (50.0%) cases of intestinal-type adenocarcinoma, 7 (43.75%) cases of diffuse-type adenocarcinoma and 1 (6.25%) case of mixed-type adenocarcinoma. During the follow-up after treatment, none of the patients was diagnosed with local or distant recurrence.

Conclusions

Accurate examination technique allows for detection of early gastric cancer. Selected cases of early gastric cancer may be treated with advanced endoscopic techniques.

Changing Trends in Stomach Cancer Throughout the World

PURPOSE OF REVIEW

The paper aims to discuss the global trends in gastric cancer incidence in relation to important factors involved in the pathogenesis of gastric cancer.

RECENT FINDINGS

Despite a significant worldwide decline, gastric cancer remains a common cause of cancer death. The decline has been multifactorial and preceded the fall in Helicobacter pylori prevalence. The initial decline was associated with changes in food preservation and availability, especially of fresh fruits and vegetables, followed by a decline in the primary etiologic factor, H. pylori. Gastric cancer incidence remains high in East Asia, intermediate in Latin America, and low in developed countries. Significant racial/ethnic variability exists. The rapid decline in incidence in East Asia will continue as primary and secondary prevention strategies are implemented. The incidence in Latin America is unlikely to decline significantly over the next few decades given high H. pylori prevalence in the young. Ultimately, global H. pylori eradication will be needed to largely eliminate gastric cancer.

Biomarkers in Tumor Microenvironment? Upregulation of Fibroblast Activation Protein-α Correlates with Gastric Cancer Progression and Poor Prognosis

Gastric cancer is the third leading cause of cancer-related mortality worldwide. Recent evidence points to importance of cross talk between cancer cells and the surrounding stroma on gastric cancer progression. Tumor microenvironment biomarkers thus represent a new opportunity for diagnostics innovation. Reactive stromal fibroblasts selectively express the fibroblast activation protein alpha (FAP-α), a homodimeric integral membrane gelatinase that belongs to the serine protease family. We report here that FAP-α expression is significantly elevated in gastric cancer samples by more than fivefold (p < 0.05), using transcriptome data from The Cancer Genome Atlas. Notably, the greatest FAP-α upregulation was observed in the poorly differentiated group (p < 0.001). Moreover, elevated FAP-α expression levels correlated with adverse clinical-pathological characteristics, such as diffuse histological subtype (p < 0.001), advanced pathological stage (p < 0.01) and poor survival. Functional annotation analysis demonstrated that FAP-α upregulation was associated with activation of biological processes implicated in tumor progression, including cell migration and angiogenesis pathways. These observations underscore the possible prognostic significance of FAP-α in gastric cancer and its potential as a novel biomarker for personalized medicine. We caution, however, that further multiomics, biochemical, and animal studies are necessary to ascertain the role of FAP-α as a causative and mechanistic biomarker. Based on pathway analyses, we hypothesize that gastric cancer patients exhibiting FAP-α upregulation might presumably benefit from antiangiogenic drugs in addition to standard therapeutic regimens. We call for future research focusing on the tumor microenvironment biomarkers in clinical oncology.

miR-205 regulation of ICT1 has an oncogenic potential via promoting the migration and invasion of gastric cancer cells

Immature colon carcinoma transcript-1 (ICT1) is a newly identified oncogene, which regulates mobility, apoptosis, cell cycle progression and proliferation of cancer cells. Nevertheless, the role of ICT1 and its clinical significance in gastric cancer (GC) is largely uncovered. Here, we found that ICT1 displayed higher expression in GC tissues compared to corresponding tumor-adjacent tissues. Further investigation confirmed ICT1 overexpression in GC cell lines. Clinical data disclosed that high ICT1 expression correlated with distant metastasis and advanced tumor-node-metastasis (TNM) stage. The Cancer Genome Atlas (TCGA) data further demonstrated that GC tissues with metastasis showed a significant higher level of ICT1 compared to those without metastasis. Furthermore, ICT1 overexpression notably predicted poor prognosis of GC patients. Functionally, we demonstrated that ICT1 knockdown suppressed invasion and migration of MGC-803 and BGC-823 cells in vitro. ICT1 overexpression promoted the mobility of SGC-7901 cells. Mechanistically, microRNA-205 (miR-205) was recognized as a direct down-regulator and inversely modulated ICT1 abundance in GC cells. miR-205 expression was down-regulated and negatively associated with ICT1 level in GC tissues. Underexpression of miR-205 indicated an obvious shorter survival of GC patients. miR-205 overexpression inhibited migration and invasion of MGC-803 cells, while these inhibitory effects were reversed by ICT1 restoration. Taken together, we have the earliest evidence that miR-205 regulation of ICT1 functions as an oncogene and prognostic biomarker in GC.

MicroRNA-216a inhibits the metastasis of gastric cancer cells by targeting JAK2/STAT3-mediated EMT process

MicroRNAs (miRNAs), a group of small, non-protein coding, endogenous RNAs, play critical roles in the tumorigenesis and progression of human cancer. miR-216a has recently been reported to play an oncogenic role in human cancer. While, the expression of miR-216a, its biological function and underlying molecular mechanisms in gastric cancer (GC) are largely unknown. In this study, we revealed that miR-216a was underexpressed in GC tissues compared to matched noncancerous tissues. Decreased levels of miR-216a were confirmed in GC cell lines compared with a normal gastric epithelium cell line. miR-216a underexpression was associated with malignant prognostic features including lymph node metastasis, venous infiltration, invasive depth and advanced TNM stage. GC patients with low miR-216a level showed an obvious shorter overall survival. miR-216a overexpression restrained migration and invasion of MGC-803 cells, while its knockdown exerted opposite effects on metastatic behaviors of SGC-7901 cells. In vivo experiments found that miR-216a restoration reduced metastatic nodes of GC cells in nude mice liver. miR-216a notably suppressed epithelial-mesenchymal transition (EMT) of GC cells. Janus kinase 2 (JAK2) was recognized as a direct target and downstream mediator of miR-216a in GC cells. Interestingly, JAK2/signal transducer and activator of transcription 3 (STAT3) pathway was prominently inactivated by miR-216a and probably mediated the role of miR-216a in the regulation of migration, invasion and EMT process of GC cells. In conclusion, these data suggest that miR-216a functions as a tumor suppressive miRNA in the development of GC possibly by targeting JAK2/STAT3-mediated EMT.

Age-specific impact on the survival of gastric cancer patients with distant metastasis: an analysis of SEER database

The age-specific impact on the survival of gastric cancer patients with distant metastasis is still unclear. In this study, we identified 11, 299 gastric cancer patients with distant metastasis between 2004 and 2013 from Surveillance, Epidemiology, and End Results population-based dataset. Patients were divided into young (≤60) and elderly groups (>60). Kaplan-Meier methods and multivariable Cox regression were used for the analysis of long-term survival outcomes and risk factors. There were significant differences between the two groups in terms of race, primary site, grade, histologic type, surgery, marital status and clinical T stage (P<0.05). The 1- and 3-year cancer specific survival rates were 29.0% and 6.2% in young group and 22.8% and 4.8% in elderly group in both univariate (X²=116.430, P<0.001) and multivariate analysis (P<0.001). Young patients had significantly better 1- and 3-year cancer specific survival than elderly patients in each T stage. Age was further validated as an independent survival factor in all T stages (T1, T2, T3, T4 and T_X, P<0.05). In conclusion, age was an independent prognostic factor for gastric cancer patients with distant metastasis.

SMURF1 promotes the proliferation, migration and invasion of gastric cancer cells

Smad ubiquitin regulatory factor 1 (SMURF1), a well-known E3 ubiquitin ligase, targets substrate proteins for ubiquitination and proteasomal degradation. Accumulating studies have shown that SMURF1 acts as an oncogenic factor in human malignancies. However, the clinical significance of SMURF1 and its role in gastric cancer (GC) remain unclear. The expression of SMURF1 was detected in 68 cases of GC and corresponding tumor-adjacent specimens. Our results revealed that SMURF1 was prominently overexpressed in GC specimens compared to corresponding tumor-adjacent tissues. Furthermore, increased levels of SMURF1 mRNA were also observed in GC cell lines. Clinicopathological detection ascertained that SMURF1-positive expression was associated with large tumor size, more lymph nodes and distant metastasis as well as advanced tumor-node-metastasis (TNM) stage of GC. Notably, GC patients with SMURF1 positive‑expressing tumors exhibited a significant decreased survival. Further experiments illustrated that SMURF1 knockdown significantly inhibited proliferation, migration and invasion of MGC-803 cells, while SMURF1 overexpression prominently promoted these behaviors in SGC-7901 cells. In vivo studies revealed that SMURF1 knockdown markedly inhibited tumor growth and liver metastasis of GC. Mechanically, SMURF1 inversely regulated the expression of DOC-2/DAB2 interactive protein (DAB2IP) in GC tissues and cells. Furthermore, DAB2IP restoration revealed similar effects to SMURF1 knockdown on MGC-803 cells with decreased proliferation, migration and invasion. In addition, the PI3K/Akt pathway and its downstream targets including c-Myc and ZEB1 were potentially involved in the oncogenic role of the SMURF1/DABIP axis. Collectively, the present study revealed the first evidence that SMURF1 can be potentially used as a clinical biomarker and target for novel treatment of human GC.

miR-944 inhibits metastasis of gastric cancer by preventing the epithelial-mesenchymal transition via MACC1/Met/AKT signaling

MicroRNAs (miRNAs) are reported to play vital roles in tumor progression. Recently, miR-944 was reported to play either an oncogenic or tumor suppressive role in human cancers. However, the expression of miR-944 and its exact role in gastric cancer (GC) remain unknown. This study aimed to evaluate whether loss of miR-944 could promote the epithelial-mesenchymal transition (EMT) of GC. Reduced expression of miR-944 was identified in 40 pairs of human GC and matched normal tissues by qRT-PCR. Reduced expression of mi-944 was also observed in GC cell lines. Restoration of miR-944 inhibited cell migration and invasion in MGC-803 cells, while its loss facilitated metastasis of SGC-7901 and BGC-823 cells. Notably, miR-944 overexpression prohibited EMT of GC cells in vitro, while miR-944 knockdown had the opposite effect. Bioinformatics software predicted that MACC1 was a direct target of miR-944. We observed negative regulation of miR-944 on MACC1 expression, and direct binding between miR-944 and MACC1 was verified by dual-luciferase assays in HEK293T cells. Restoration of MACC1 resulted in promoted EMT and metastasis in miR-944-overexpressing MGC-803 cells. Loss of MACC1 abrogated the effects of miR-944 knockdown on EMT and metastasis of SGC-7901 cells. We also found that the Met-AKT pathway might be involved in MACC1-mediated EMT. In conclusion, miR-944 acts as an inhibitor of EMT and metastasis of GC by targeting MACC1. This study highlights the potential effects of miR-944 in the prognosis and treatment of GC.

The novel long noncoding RNA RP11-357H14.17 acts as an oncogene by promoting cell proliferation and invasion in diffuse-type gastric cancer

Current evidence indicates that long noncoding RNAs (lncRNAs) play pivotal roles in human cancers. The present study aims to assess differentially expressed lncRNAs related to diffuse-type gastric carcinoma (DGC). Next-generation RNA sequencing was carried out to detect aberrantly expressed lncRNAs in DGC. Real-time polymerase chain reaction (RT-PCR) was performed to evaluate RP11–357H14.17 gene expression levels in DGC cell lines/tissues comparatively with normal gastric epithelial cell lines and adjacent normal tissues. The associations of RP11–357H14.17 expression levels with the clinicopathological features were also analyzed. The regulatory effects of RP11–357H14.17 on the biological behaviors of DGC cells were evaluated by MTT, colony formation assays, flow cytometry for apoptosis, wound healing assay, and transwell migration and invasion assays. RP11–357H14.17 expression was remarkably increased in DGC tissues and cell lines compared with normal gastric epithelial cells and adjacent normal tissues. High levels of RP11–357H14.17 were associated with increased tumor size, deeper depth of invasion, lymphatic metastasis, and advanced pathological stage. Further experiments demonstrated that the DGC cells MGC-803 transfected with si-RP11–357H14.17 showed reduced cell proliferation, migration, invasion, enhanced G1 phase arrest and cell apoptosis. These findings suggest that the novel lncRNA RP11–357H14.17 is associated with poor prognosis, and may serve as a potential prognostic biomarker and target for new antineoplastic therapies in human DGC.

Past and current trends in endoscopic diagnosis for early stage gastric cancer in Japan

Methodology for the diagnosis and staging of early gastric cancer (EGC) has improved in Japan since the development of the gastro-camera and determination of a definition of EGC. Imaging technology has been steadily evolving in the endoscopy field. Improvements in the resolution of standard endoscopy images used in screening and surveillance provide greater opportunities to find gastric cancer earlier. Image enhancement endoscopy (IEE), such as narrow band imaging (NBI), highlights mucosal structures and vascularity. In particular, when NBI is used with magnifying endoscopy, it reveals fine details of subtle superficial abnormalities of EGC that are difficult to recognize using standard white light endoscopy. IEE-assisted magnifying endoscopy has improved the accuracy of the differentiation of superficial gastric cancer as well as delineation of the diseased mucosa. The advanced imaging technology enables precise assessment of the risk of lymph node metastasis of EGC and is widely used to determine indications for endoscopic treatment. It is not an overstatement to say that this has become the basis for the current development and dissemination of endoscopic treatments. Moreover, the resolution of endoscopic imaging has been upgraded to the microscopy level by the development of endomicroscopy, including endocytoscopy and confocal laser endomicroscopy. Endomicroscopy allows real-time histological analysis of living tissue during routine endoscopy and may reduce the number of biopsies needed to reach the correct diagnosis, minimizing the risk of sampling errors.