Gene deregulation in gastric cancer

The global prevalence of gastric cancer in Helicobacter pylori-infected individuals: a systematic review and meta-analysis

BACKGROUND

Helicobacter pylori is a gastrointestinal pathogen that infects around half of the world's population. H. pylori infection is the most severe known risk factor for gastric cancer (GC), which is the second highest cause of cancer-related deaths globally. We conducted a systematic review and meta-analysis to assess the global prevalence of GC in H. pylori-infected individuals.

METHODS

We performed a systematic search of the PubMed, Web of Science, and Embase databases for studies of the prevalence of GC in H. pylori-infected individuals published from 1 January 2011 to 20 April 2021. Metaprop package were used to calculate the pooled prevalence with 95% confidence interval. Random-effects model was applied to estimate the pooled prevalence. We also quantified it with the I2 index. Based on the Higgins classification approach, I2 values above 0.7 were determined as high heterogeneity.

RESULTS

Among 17,438 reports screened, we assessed 1053 full-text articles for eligibility; 149 were included in the final analysis, comprising data from 32 countries. The highest and lowest prevalence was observed in America (pooled prevalence: 18.06%; 95% CI: 16.48 - 19.63; I2: 98.84%) and Africa (pooled prevalence: 9.52%; 95% CI: 5.92 - 13.12; I2: 88.39%). Among individual countries, Japan had the highest pooled prevalence of GC in H. pylori positive patients (Prevalence: 90.90%:95% CI: 83.61-95.14), whereas Sweden had the lowest prevalence (Prevalence: 0.07%; 95% CI: 0.06-0.09). The highest and lowest prevalence was observed in prospective case series (pooled prevalence: 23.13%; 95% CI: 20.41 - 25.85; I2: 97.70%) and retrospective cohort (pooled prevalence: 1.17%; 95% CI: 0.55 - 1.78; I 2: 0.10%).

CONCLUSIONS

H. pylori infection in GC patients varied between regions in this systematic review and meta-analysis. We observed that large amounts of GCs in developed countries are associated with H. pylori. Using these data, regional initiatives can be taken to prevent and eradicate H. pylori worldwide, thus reducing its complications.

Current standards of surgical management of gastric cancer: an appraisal

PURPOSE

Gastric cancer (GC) is the fifth most common malignancy worldwide and portends a grim prognosis due to a lack of appreciable improvement in 5-year survival. We aimed to analyze the available literature and summarize the current standards of surgical care for curative and palliative intent treatment of GC.

METHODS

We conducted a systematic search on the PubMed database for studies on the management of GC.

RESULTS

Endoscopic resection is an acceptable treatment option for T1a tumors. The role of optimal resection margin for GC remains unclear. D2 lymph node dissection remains the standard of care with splenectomy needed selectively for splenic hilum involvement. A distal pancreatic resection should be avoided. The advantage of bursectomy and omentectomy in GC surgery is not clear. Multi-visceral resection may be considered for locally advanced GC in carefully selected patients. Minimally invasive approaches are non-inferior to open surgery. Surgery should be abandoned prior even in metastatic GC within the frame of multimodal therapy approach.

CONCLUSION

Various trials have conclusively shown improved patient outcomes when well-established surgical standards are followed.

Benzyl Isothiocyanate-Induced Cytotoxicity via the Inhibition of Autophagy and Lysosomal Function in AGS Cells

Gastric adenocarcinoma is among the top causes of cancer-related death and is one of the most commonly diagnosed carcinomas worldwide. Benzyl isothiocyanate (BITC) has been reported to inhibit the gastric cancer metastasis. In our previous study, BITC induced apoptosis in AGS cells. The purpose of the present study was to investigate the effect of BITC on autophagy mechanism in AGS cells. First, the AGS cells were treated with 5, 10, or 15 μM BITC for 24 h, followed by an analysis of the autophagy mechanism. The expression level of autophagy proteins involved in different steps of autophagy, such as LC3B, p62/SQSTM1, Atg5-Atg12, Beclin1, p-mTOR/mTOR ratio, and class III PI3K was measured in the BITC-treated cells. Lysosomal function was investigated using cathepsin activity and Bafilomycin A1, an autophagy degradation stage inhibitor. Methods including qPCR, western blotting, and immunocytochemistry were employed to detect the protein expression levels. Acridine orange staining and omnicathepsin assay were conducted to analyze the lysosomal function. siRNA transfection was performed to knock down the LC3B gene. BITC reduced the level of autophagy protein such as Beclin 1, class III PI3K, and Atg5-Atg12. BITC also induced lysosomal dysfunction which was shown as reducing cathepsin activity, protein level of cathepsin, and enlargement of acidic vesicle. Overall, the results showed that the BITC-induced AGS cell death mechanism also comprises the inhibition of the cytoprotective autophagy at both initiation and degradation steps.

Pretreatment serum albumin-to-alkaline phosphatase ratio is an independent prognosticator of survival in patients with metastatic gastric cancer

BACKGROUND

Previous studies have suggested that a low albumin-to-alkaline phosphatase ratio (AAPR) is associated with a lower survival rate in patients with various malignancies. However, the relationship between pretreatment AAPR and the prognosis of patients with gastric cancer (GC) remains unclear.

AIM

To investigate the prognostic value of AAPR in distant metastatic GC.

METHODS

A total of 191 patients with distant metastatic cancer from a single institute were enrolled in this study. Pretreatment clinical data, including serum albumin and alkaline phosphatase levels, were collected. A chi-square test or Fisher’s exact test was applied to evaluate the correlations between AAPR and various clinical parameters in GC patients. The Kaplan–Meier method and Cox proportional hazards regression model were used to evaluate the prognostic efficacy of AAPR in metastatic GC patients. A two-sided P value lower than 0.05 was considered statistically significant.

RESULTS

A receiver operating characteristic curve indicated that 0.48 was the optimal threshold value for AAPR. AAPR ≤ 0.48 was significantly associated with bone (P < 0.05) and liver metastasis (P < 0.05). Patients with high levels of AAPR had better survival in terms of overall survival (OS) and progression-free survival (PFS), regardless of the presence of liver/bone metastasis. Pretreatment AAPR was found to be a favorable predictor of OS and PFS based on a multivariate cox regression model. AAPR-M system, constructed based on AAPR and number of metastatic sites, showed superior predictive ability relative to the number of metastatic sites for predicting survival.

CONCLUSION

Pretreatment AAPR may serve as an independent prognostic factor for predicting PFS and OS in patients with metastatic GC. Furthermore, AAPR may assist clinicians with individualizing treatment.

Long noncoding RNA BBOX1-AS1 promotes the progression of gastric cancer by regulating the miR-361-3p/Mucin 13 signaling axis

Gastric cancer (GC) places a heavy burden on global health, and the information on the molecular mechanism of the progression of GC is still inadequate. Long noncoding RNA (LncRNA) has been confirmed to be widely involved in regulating the progression of GC. Our aim in this study was to explore the role and potential regulatory mechanism of lncRNA BBOX1-AS1 in GC. The expression levels of BBOX1-AS1, miR-361-3p, and MUC13 in GC tissues and cells were evaluated using quantitative real-time polymerase chain reaction and western blotting. The silencer of BBOX1 antisense RNA 1 (BBOX1-AS1) and mucin 13 (MUC13), the mimics and inhibitor of miR-361-3p, and their negative controls were used to alter the expression of these genes. Luciferase reporter, pull-down, and RNA immunoprecipitation assays were performed to verify the correlation between miR-361-3p, BBOX1-AS1, and MUC13. GC cell proliferation, invasion, and apoptosis were detected by cell counting kit-8, transwell, and flow cytometry assays, respectively. An in vivo functional experiment was performed to assess the effect of BBOX1-AS1 on GC. The results showed that BBOX1-AS1 was significantly upregulated in GC tissues. Silencing of BBOX1-AS1 inhibited GC cell proliferation and invasion and inhibited tumor growth in vivo, whereas it promoted apoptosis. MiR-361-3p was significantly downregulated in GC and counteracted the inhibitory effects of BBOX1-AS1 on GC progression. MUC13, which is targeted by miR-361-3p, is significantly upregulated in GC. MUC13 silencing inhibited GC progression was aborgated by miR-361-3p inhibitor. Collectively, BBOX1-AS1 silencing inhibits GC progression by regulating the miR-361-3p/MUC13 axis, providing a potential therapeutic biomarker for GC.

The efficiency of D1(+) lymphadenectomy in signet ring cell carcinoma: comparison of postoperative early and late outcomes between standard lymphadenectomy and D1(+) lymphadenectomy

Signet ring cell carcinoma (SRCC) is a poorly cohesive subtype of gastric cancer. It is more aggressive than other types of gastric cancer. There is no special method for its treatment, but gastrectomy and lymphadenectomy is the standard approach. The aim of this study is to investigate postoperative outcomes of D1 lymphadenectomy and D1(+)lymphadenectomy in gastric SRCC.

A total of 358 cases whohad a gastrectomy performed forthe diagnosis of gastric cancer between 2013 and 2019 in Ankara University Medical Faculty, Surgical Oncology Department were retrospectively investigated. In all, 128 of the cases had SRCC in the final pathology. We separated the cases into two types,D1 lymphadenectomy and D1(+) lymphadenectomy. The 5-year survival, early mortality, hospital mortality and postoperative complication rates were evaluated.

There were 59 patients in the D1 group and 64 patients in the D1(+) group.Metastatic lymph node amount and therefore N stage was found to be significantly higher in the D1(+) group (p=0.00 and p=0.03, respectively). Postoperative chyle fistula was found to be significantly higher in the D1(+) group (p=0.003). There was no statistically significant difference between the groups with regard tomean survival (p=0.065);the 5-year mean survival was 21% in the D1 group and 7% in the D1(+) group. Present findings suggest that extended lymphadenectomy does not provide a benefit in cases of SRCC.

Development of a Novel Anti-HER2 Monoclonal Antibody H2Mab-181 for Gastric Cancer

Human epidermal growth factor receptor 2 (HER2) is a type I transmembrane 185 kDa protein. HER2 is expressed in a variety of normal tissue types and cancer cells. HER2 is associated with cell proliferation, differentiation, and migration. The overexpression of HER2 has been observed in a number of cancers, including breast and gastric cancers. Gastric cancer is one of the most common cancers worldwide, with an annual case rate of ∼1 million people diagnosed with the disease. Trastuzumab is a humanized anti-HER2 monoclonal antibody (mAb) that has been utilized in gastric cancer therapy. In this study, we have developed a novel anti-HER2 mAb, H₂Mab-181 (IgG₁, kappa), through the immunization of mice with a purified recombinant extracellular domain of HER2. H₂Mab-181 can specifically and sensitively detect HER2 in both flow cytometry and Western blot applications in gastric cancer cell lines and can also be utilized in immunohistochemical analyses of gastric cancer tissues. Together, H₂Mab-181 could be useful for the diagnosis and therapy in gastric cancers.

Helicobacter pylori Infection in Tripoli, North Lebanon: Assessment and Risk Factors

Helicobacter pylori (H. pylori) infection occurs among half of the general population worldwide, with high geographic variability. Even though H. pylori is the leading cause of several gastric diseases, ranging from gastritis and peptic ulcers to gastric malignancies, such as gastric cancer and mucosa-associated lymphoid tissue lymphoma, most of the infections remain asymptomatic. Early detection and eradication of H. pylori can definitely prevent severe long-term gastric diseases associated with H. pylori. In Lebanon, the prevalence of H. pylori is not well documented, especially in healthy subjects. The aim of this study is to assess H. pylori infections and the associated risk factors in Tripoli, North Lebanon. A cross-sectional study was conducted on 300 healthy Lebanese volunteers, including both children and adults. The H. pylori stool antigens were detected using the Premier Platinum HpSA test. The socio-demographic data, lifestyle characteristics, and gastrointestinal characteristics of all participants were analyzed. Out of the 300 tested volunteer subjects, 31% were found to be positive for H. pylori. A multivariate binary logistic regression analysis for factors associated with H. pylori infection revealed a significant association between H. pylori infection and gastrointestinal disturbances, the crowding index, and occupation. A significant statistical correlation was found between sheesha smoking (p = 0.001) and H. pylori infection. These findings highlight the need for the development of preventive approaches and strategic indications for the appropriate treatment of H. pylori infections in Tripoli, North Lebanon.

Roles of Nrf2 in Gastric Cancer: Targeting for Therapeutic Strategies

Nuclear Factor Erythroid 2-Related Factor 2 (Nrf2) is a specific transcription factor with potent effects on the regulation of antioxidant gene expression that modulates cell hemostasis under various conditions in tissues. However, the effects of Nrf2 on gastric cancer (GC) are not fully elucidated and understood. Evidence suggests that uncontrolled Nrf2 expression and activation has been observed more frequently in malignant tumors, including GC cells, which is then associated with increased antioxidant capacity, chemoresistance, and poor clinical prognosis. Moreover, Nrf2 inhibitors and the associated modulation of tumor cell redox balance have shown that Nrf2 also has beneficial effects on the therapy of various cancers, including GC. Based on previous findings on the important role of Nrf2 in GC therapy, it is of great interest to scientists in basic and clinical tumor research that Nrf2 can be active as both an oncogene and a tumor suppressor depending on different background situations.

Recent advances of miRNAs in the development and clinical application of gastric cancer

Gastric cancer (GC) is one of the most common malignant tumors. The mechanism of how GC develops is vague, and therapies are inefficient. The function of microRNAs (miRNAs) in tumorigenesis has attracted the attention from many scientists. During the development of GC, miRNAs function in the regulation of different phenotypes, such as proliferation, apoptosis, invasion and metastasis, drug sensitivity and resistance, and stem-cell-like properties. MiRNAs were evaluated for use in diagnostic and prognostic predictions and exhibited considerable accuracy. Although many problems exist for the application of therapy, current studies showed the antitumor effects of miRNAs. This paper reviews recent advances in miRNA mechanisms in the development of GC and the potential use of miRNAs in the diagnosis and treatment of GC.

Clinicopathological profile and its association with peritoneal disease among gastric cancer patients

BACKGROUND

There are no clinicopathological criteria or test to predict peritoneal metastasis either in primary or recurrent gastric cancer. The early prediction will help in altering or adding other adjuvant potential therapy modalities like HIPEC and maintenance chemotherapy.

METHODS

Paraffin based blocks of 110 gastric tumor specimens were subjected to IHC staining to assess VEGF, Her 2 neu, E cadherin, bcl 2 and p 53 expression and its association with peritoneal disease evaluated.

RESULTS

Her 2 neu uptake was present in 17.3%, bcl-2 expression in 19.1%, P53 expression in 40.9%, VEGF in 41.8% and E cadherin expression in 49.1% patients. On univariate analysis, a younger age(p = .029), female sex(p = .026), positive VEGF expression (p = .001) and p53 expression(p = .015) were significantly associated with peritoneal disease. A binomial logistic regression was performed to ascertain the effects of independent variables evaluated on univariate analysis. Of the 10 predictors variables, only three were statistically significant: tumor type, P53, and VEGF. Positive VEGF expression had 48.7, E cadherin 2.6 and Her2neu 1.5 times higher odds of exhibiting peritoneal disease.

CONCLUSION

A younger age, female sex, distal 2/3rd, diffuse variant, VEGF staining in >10% cells and decrease p53 expression were associated with peritoneal disease.

Upregulation of miR-1307-3p and its function in the clinical prognosis and progression of gastric cancer

Gastric cancer is one of the major causes of cancer-associated mortality worldwide. miR-1307-3p has been demonstrated to serve multiple roles in the development of various types of cancer. The present study aimed to evaluate the expression and functional role of miR-1307-3p in the progression of gastric cancer. The expression of miR-1307-3p in gastric cancer tissues and cell lines was detected by reverse transcription quantitative PCR. Furthermore, the correlation between miR-1307-3p expression and the clinicopathological characteristics and prognosis of patients was evaluated. Cell Counting Kit-8 and Transwell assays were performed to analyze the effects of miR-1307-3p on the proliferation and the migratory and invasive abilities of gastric cancer cells, respectively. Dual-luciferase reporter assay was conducted to reveal the potential underlying mechanism of miR-1307-3p. In gastric cancer tissues and cells, miR-1307-3p expression was significantly upregulated compared with the normal tissues and cell lines. In addition, the expression of miR-1307-3p was associated with the Tumor-Node Metastasis stage of patients. The results from Cox regression analysis demonstrated that miR-1307-3p may serve as an independent predictor for the prognosis of patients with gastric cancer. Furthermore, the upregulation of miR-1307-3p in gastric cancer cell lines significantly promoted the cell proliferation and migratory and invasive abilities by targeting DAB2 interacting protein. In conclusion, the findings from the present study suggested that miR-1307-3p may serve as a tumor promoter of gastric cancer and that miR-1307-3p expression in tumor tissues may be used as a prognostic indicator for patients with gastric cancer.

miR-4636 inhibits tumor cell proliferation, migration and invasion, and serves as a candidate clinical biomarker for gastric cancer

Gastric cancer (GC) is one of the most common malignancies with a high worldwide incidence rate. The association between microRNAs (miRs) and malignancy has been widely studied in recent years. The aim of the present study was to assess the clinical value of miR-4636 in patients with GC and its effect on the proliferation, migration and invasion of GC cells. Reverse transcription-quantitative PCR was used to detect the expression of miR-4636. Receiver operating characteristics curve, Kaplan-Meier survival curve and Cox regression analyses were used to evaluate the diagnostic and prognostic value of miR-4636. Transwell migration and MTT assays were used to assess the regulatory effects of miR-4636 expression on the biological function of GC. The results demonstrated that the expression of miR-4636 was significantly downregulated in GC serum and tissue samples, as well as in GC cell lines. The aberrant miR-4636 expression was closely associated with lymph node metastasis and TNM stage, and had considerable diagnostic and prognostic significance in patients with GC. Cellular experiments revealed that the overexpression of miR-4636 inhibited GC cell proliferation, migration and invasion, while the knockdown of miR-4636 led to opposite effects on the biological function of GC. In summary, decreased miR-4636 expression may serve as a biomarker for the diagnosis and prognosis of GC. Furthermore, miR-4636 overexpression significantly inhibited GC cell proliferation, migration and invasion, indicating the potential of miR-4636 as a therapeutic target for GC treatment.

Efficacy of Chronomodulated Chemotherapy for Palliation of Hematemesis in Inoperable Gastric Cancer: A Single-Institutional Retrospective Study

Context:

Aside abdominal discomfort and pain, upper gastrointestinal bleeding (UGIB) significantly disgraces the quality of life (QoL), especially in inoperable gastric cancer patients. Although, in early stages, it is infrequent and often ignored, but in advanced stages, its aggressiveness often deteriorates patient's hemoglobin (Hb) level and performing status.

Aim:

The aim of this study is to correlate the change in (1) the frequency of episodes of UGIB, (2) its severity in terms of Common Terminology Criteria for Adverse Events (CTCAE) grade for UGIB, and (3) Hb level with the successful completion of successive cycles of palliative chemotherapy where it becomes invariably the only modality to palliate the cancer disease.

Setting and Design:

This single-institutional retrospective observational study included seventy gastric carcinoma patients with a chief complaint of frequent hematemesis. They were divided according to the cause behind inoperability or irresectability: (1) Metastatic disease, (2) locally advanced irresectable disease, (3) uncontrolled comorbidities, (4) poor GC (PGC), and (5) refused to give surgical consent.

Subjects and Methods:

Following baseline evaluation and prechemotherapy workups, patients were subjected to three-weekly chronomodulated modified EOX regimen. Relevant parameters, i.e., (1) average episodes per-week (AEP) score, (2) Hb, and (3) average CTCAE grade value for UGIB were recorded after every cycle.

Results:

At 12-week follow-up, there was a significant decrease in mean AEP score from baseline (from 2.6691 ± 0.7047 to 1.5033 ± 0.6272) for the entire cohort (P < 0.001). Maximum benefit in terms of mean Hb (increase by 1.0737% above baseline) took place for PGC group (P < 0.001). Mean CTCAE grade value for the entire cohort decreased from baseline by 0.6428, which was statistically significant with a P < 0.001.

Conclusions:

PGC group was maximally benefited considering all three parameters. Though surgery defines the mainstay of treatment for gastric carcinoma, yet in inoperable cases, only chronomodulated chemotherapy significantly affects the severity of UGIB and thus may improve QoL.

Effect of a psychological nursing intervention on quality of life and cognitive function in patients with gastric carcinoma: A randomised controlled trial

AIM

We aimed to evaluate the effect of a psychological nursing intervention on quality of life (QoL) and cognitive function in patients with gastric carcinoma (GC) and proposed that the intervention might improve the QoL and cognitive function of GC patients.

METHODS

Gastric carcinoma patients were randomly assigned into two groups: (a) intervention group: receiving proper psychological nursing intervention; (b) control group: receiving conventional care.

RESULTS

The QoL and Montreal Cognitive Assessment (MoCA) scores at each dimensionality between the intervention group and the control group at baseline showed no significant differences (p > .05). However, after the 6-month psychological nursing intervention, 5 of 10 dimensionalities in QoL and 5 of 6 dimensionalities in MoCA showed statistically differences between the intervention group and the control group (p < .05). In comparison with the scores at baseline, the QoL scores measured after the 6-month psychological nursing intervention showed remarkable improvement in multiple dimensionalities in the intervention group, but only appetite loss improved in the control group. MoCA scores in multiple dimensionalities in the intervention group also exhibited obvious improvement compared with those in control group.

CONCLUSION

A psychological nursing intervention benefits the QoL and cognitive function in GC patients, indicating the importance of a psychological nursing intervention.

Fluoxetine Simultaneously Induces Both Apoptosis and Autophagy in Human Gastric Adenocarcinoma Cells

Fluoxetine is used widely as an antidepressant for the treatment of cancer-related depression, but has been reported to also have anti-cancer activity. In this study, we investigated the cytotoxicity of fluoxetine to human gastric adenocarcinoma cells; as shown by the MTT assay, fluoxetine induced cell death. Subsequently, cells were treated with 10 or 20 µM fluoxetine for 24 h and analyzed. Apoptosis was confirmed by the increased number of early apoptotic cells, shown by Annexin V- propidium iodide staining. Nuclear condensation was visualized by DAPI staining. A significant increase in the expression of cleaved PARP was observed by western blotting. The pan-caspase inhibitor Z-VAD-FMK was used to detect the extent of caspase-dependent cell death. The induction of autophagy was determined by the formation of acidic vesicular organelles (AVOs), which was visualized by acridine orange staining, and the increased expression of autophagy markers, such as LC3B, Beclin 1, and p62/SQSTM 1, observed by western blotting. The expression of upstream proteins, such as p-Akt and p-mTOR, were decreased. Autophagic degradation was evaluated by using bafilomycin, an inhibitor of late-stage autophagy. Bafilomycin did not significantly enhance LC3B expression induced by fluoxetine, which suggested autophagic degradation was impaired. In addition, the co-administration of the autophagy inhibitor 3-methyladenine and fluoxetine significantly increased fluoxetine-induced apoptosis, with decreased p-Akt and markedly increased death receptor 4 and 5 expression. Our results suggested that fluoxetine simultaneously induced both protective autophagy and apoptosis and that the inhibition of autophagy enhanced fluoxetine-induced apoptosis through increased death receptor expression.

WGCNA Co-Expression Network Analysis Reveals ILF3-AS1 Functions as a CeRNA to Regulate PTBP1 Expression by Sponging miR-29a in Gastric Cancer

Gastric cancer (GC) is one of the most common types of human cancers worldwide. However, the detail mechanisms underlying GC progression remained to be investigated. The present study identified 2823 differently expressed mRNAs and 441 differently expressed lncRNAs in GC. WGCNA was conducted to identify highly correlated lncRNAs and mRNAs. Bioinformatics analysis observed that these dysregulated lncRNAs were significantly associated with the regulation of angiogenesis, cell division, cell-cell adhesion, blood vessel development, adaptive immune response, gastric acid secretion, immune response. Co-expression analysis identified ILF3-AS1 was a key lncRNA involved in regulating GC progression. Loss of function assays showed that knockdown of ILF3-AS1 significantly suppressed GC cell proliferation and metastasis. Mechanically, the results indicate that ILF3-AS1 could enhance PTBP3 expression as an miR-29a sponge, thereby promoting the proliferation and metastasis of GC cells. Our work suggests that the ILF3-AS1/miR-29a/PTBP3 axis may be a potential target for the clinical diagnosis and treatment of GC.

Update on gastric cancer treatments and gene therapies

Gastric cancer is an active topic of clinical and basic research due to high morbidity and mortality. To date, gastrectomy and chemotherapy are the only therapeutic options for gastric cancer patients, but drug resistance, either acquired or primary, is the main cause for treatment failure. Differences in development and response to cancer treatments have been observed among ethnically diverse GC patient populations. In spite of major incidence, GC Asian patients have a significantly better prognosis and response to treatments than Caucasian ones due to genetic discordances between the two populations. Gene therapy could be an alternative strategy to overcome such issues and especially CRISPR/Cas9 represents one of the most intriguing gene-editing system. Thus, in this review article, we want to provide an update on the currently used therapies for the treatment of advanced GC. Graphical abstract.

RP11-81H3.2 promotes gastric cancer progression through miR-339-HNRNPA1 interaction network

Recent studies have demonstrated that various long non-coding RNAs (lncRNAs) participate in the gastric cancer (GC) development and metastasis. Some lncRNAs exert their regulatory function by interacting with microRNAs. Here we identified a novel lncRNA RP11-81H3.2 that was highly expressed in the GC tissue and cell lines. RP11-81H3.2 knockdown significantly inhibited the proliferation, migration, and invasion of GC cells. Mechanistically, we demonstrated that RP11-81H3.2 directly interacted with miR-339 while miR-339 regulated the HNRNPA1 expression by targeting HRRNPA1 3'-UTR. RP11-81H3.2-miR-339-HNRNPA1 interaction network regulated the GC cell proliferation, migration, and invasion. Moreover, our results confirmed that RP11-81H3.2 knockdown suppressed the tumor growth of GC in a xenograft model in vivo. In summary, the results suggest that RP11-81H3.2 functions as an oncogene in GC and could be utilized as a promising diagnosis and therapeutic marker for GC treatment.

LncRNA IGFL2-AS1 functions as a ceRNA in regulating ARPP19 through competitive binding to miR-802 in gastric cancer

Gastric cancer (GC) is one of the most common malignancies of the digestive system worldwide. Multiple long noncoding RNAs (lncRNAs) participate in the regulation of GC development and metastasis. In this study, we aimed to elucidate the expression and function of lncRNA IGFL2-AS1 in GC. We found that IGFL2-AS1 was highly expressed in GC tissues and cell lines. Knockdown of IGFL2-AS1 suppressed GC cell proliferation, migration, and invasion in vitro. Furthermore, we identified that IGFL2-AS1 exerted its function as a molecular sponge of miR-802. MiR-802 was demonstrated to be a tumor suppressor, and overexpression of miR-802 suppressed GC cell growth, migration, and invasion. Mechanistically, we revealed that the cAMP-regulated phosphoprotein 19 (ARPP19) was a direct target of miR-802 and could reverse the inhibitory function of miR-802. Moreover, our results confirmed that knockdown of IGFL2-AS1 inhibited GC tumor development in an in vivo GC tumor xenograft model. In summary, our data suggest that the IGFL2-AS1/miR-802/ARPP19 axis plays a critical role in the progression and metastasis of GC. Therapies targeting the IGFL2-AS1/miR-802/ARPP19 axis can potentially improve GC treatment.

High Expression of TRIM15 Is Associated with Tumor Invasion and Predicts Poor Prognosis in Patients with Gastric Cancer

BACKGROUND

Gastric cancer is the third leading cause of cancer-related mortality worldwide. Most tripartite motif (TRIM) family proteins are known as E3 ubiquitin ligases and considerable previous research has revealed the involvement of TRIM proteins in carcinogenesis. TRIM15 is a protein from the TRIM family and the aim of this study is to investigate the role of TRIM15 in gastric cancer.

METHODS

We conducted immunohistochemical staining to examine TRIM15 expression using samples from Zhongshan Hospital of Fudan University. We also conducted transwell assay as well as western blot by using gastric cancer cells.

RESULTS

The expression of TRIM15 in gastric cancer tissues was higher than normal tissues. Present data demonstrated that high TRIM15 staining intensity had a positive relation to tumor invasion depth (P = 0.007), lymph node metastasis (P = 0.013), distant metastasis (P = 0.031), the tumor-node-metastasis (TNM) staging system (P = 0.002) and shorter overall survival (OS) in gastric cancer patients (P < 0.001). It was also worthwhile mentioning that TRIM15 was an adverse prognostic variable for OS. To gain more insight, we incorporated TRIM15 expression into the tumor-node-metastasis (TNM) staging system and thus established a nomogram. Data derived from the nomogram suggested that fitting TRIM15 expression into the prognostic model exhibited better efficiency for predicting OS in gastric cancer patients. Furthermore, TRIM15 promoted migration, invasion and epithelial-mesenchymal transition of gastric cancer cells.

CONCLUSIONS

Together, TRIM15 expression was found as a specific and independent adverse predictor in gastric cancer patients and the nomogram may contribute to better clinical management.

Study of Survival in Gastric Cancer with Emphasis on Lymph Node Status as an Independent Prognostic Factor

Background: Lymph node status in gastric cancer is known as an independent prognostic factor that guides the surgical and oncological treatment and independently influences long-term survival. Several studies suggest that the lymph node ratio has a greater importance in survival than the number of metastatic lymph nodes.

Aim: The aim of this study was to evaluate the clinical and morphological factors that can influence the survival of gastric cancer patients, with an emphasis on nodal status and the lymph node ratio.

Material and methods: We conducted a retrospective study in which 303 patients with gastric cancer admitted to the Department of Surgery of the Mureș County Hospital between 2008 and 2018 were screened for study enrolment. Data were obtained from the records of the department and from the histopathological reports. The examined variables included: age, gender, tumor localization, T stage, histological type, grade of differentiation, surgical procedure, lympho-vascular invasion, excised lymph nodes, metastatic lymph nodes, lymph node ratio. After screening, the study included a total number of 100 patients, for which follow-up data was available.

Results: The mean age of the study population was 66.43 ± 10 years, and 71% were males. The average survival period was 21.42 months. Statistical analysis showed that the localization of the tumor (p = 0.021), vascular invasion (p ---lt---0.001), T (p = 0.004) and N (p ---lt---0.001) stages, type of surgery (partial gastrectomy 59% vs. total gastrectomy 41%, p = 0.005), as well as the lymph node ratio (p ---lt---0.001) were prognostic factors for survival in patients with gastric cancer undergoing surgical therapy.

Conclusions: The survival of gastric cancer patients is significantly influenced by tumor localization, T stage, vascular invasion, type of surgery, N stage and the lymph node ratio based on univariate analysis. Also, the lymph node ratio proved to be an independent prognostic factor for survival.

The effects of serum levels, and alterations in the genes of binding protein and receptor of vitamin D on gastric cancer

Due to many biological cell functions of vitamin D including regulation of cell survival, proliferation and differentiation, the metabolism of itself gains importance in the development of several types of cancer. This case-control study was designed to evaluate the risk of gastric cancer development in terms of VDR rs2228570 & rs731236, and VDBP rs7041 polymorphisms, and serum levels of vitamin D. The study consists of 77 gastric cancer patients and 84 healthy individuals. VDR and VDBP gene polymorphisms and vitamin D levels were determined by using PCR-RFLP and HPLC methods. The distribution of VDR or VDBP gene variants were not different in study groups. The serum level of 25-hydroxyvitamin D was significantly lower in gastric cancer patients versus controls (16 ± 6 → 11 ± 6 ng/ml) in which male patients have higher levels than females. Although the whole study population lacks normal levels of 25-hydroxyvitamin D, it was found that the risk of the development of gastric cancer was approximately fourfold higher in cases with severe vitamin D (< 10 ng/ml) deficiency. Our results indicate that VDR rs731236 & rs2228570 or VDBP rs7041 polymorphisms were not risk factors for the development of gastric cancer individually, however, lower serum levels of vitamin D may be a contributory risk for both predisposition and development of gastric cancer.

Hedgehog signaling induces PD-L1 expression and tumor cell proliferation in gastric cancer

Tumor cells expressing programmed cell death ligand 1 (PD-L1) interact with PD-1 on CD8+ cytotoxic T lymphocytes (CTLs) to inhibit CTL effector function. In gastric cancer, the mechanism regulating PD-L1 is unclear. The Hedgehog (Hh) signaling pathway is reactivated in various cancers including gastric. Here we tested the hypothesis that Hh-induced PD-L1 inactivates effector T cell function and allows gastric cancer cell proliferation. Mouse organoids were generated from tumors of a triple-transgenic mouse model engineered to express an activated GLI2 allele, GLI2A, in Lgr5-expressing stem cells, (mTGOs) or normal mouse stomachs (mGOs). Bone marrow-derived dendritic cells (DCs) were pulsed with conditioned media collected from normal (mGOCM) or cancer (mTGOCM) organoids. Pulsed DCs and CTLs were then co-cultured with either mGOs or mTGOs in the presence of PD-L1 neutralizing antibody (PD-L1Ab). Human-derived gastric cancer organoids (huTGOs) were used in drug and xenograft assays. Hh/Gli inhibitor, GANT-61 significantly reduced the expression of PD-L1 and tumor cell proliferation both in vivo and in vitro. PD-L1Ab treatment induced tumor cell apoptosis in mTGO/immune cell co-cultures. GANT-61 treatment sensitized huTGOs to standard-of-care chemotherapeutic drugs both in vivo and in vitro. Thus, Hh signaling mediates PD-L1 expression in gastric cancer cells and subsequently promotes tumor proliferation.

Pathological bases and clinical impact of long noncoding RNAs in prostate cancer: a new budding star

Long non-coding RNAs (lncRNAs) are functional RNAs longer than 200 nucleotides. Recent advances in the non-protein coding part of human genome analysis have discovered extensive transcription of large RNA transcripts that lack coding protein function, termed non-coding RNA (ncRNA). It is becoming evident that lncRNAs may be an important class of pervasive genes involved in carcinogenesis and metastasis. However, the biological and molecular mechanisms of lncRNAs in diverse diseases are not yet fully understood. Thus, it is anticipated that more efforts should be made to clarify the lncRNA world. Moreover, accumulating evidence has demonstrated that many lncRNAs are dysregulated in prostate cancer (PC) and closely related to tumorigenesis, metastasis, and prognosis or diagnosis. In this review, we will briefly outline the regulation and functional role of lncRNAs in PC. Finally, we discussed the potential of lncRNAs as prospective novel targets in PC treatment and biomarkers for PC diagnosis.

Up-Regulation of miR-21, miR-25, miR-93, and miR-106b in Gastric Cancer

Background:

Differential expression profile of microRNAs (miRNAs) could be a diagnosis signature for monitoring gastric cancer (GC) progression. In this study, we focus on the comparison of expression levels of miR-21, miR-25, miR-93, miR-106b, and miR-375 during the sequential pattern of GC development, including normal gastric, gastric dysplasia, and GC sample.

Methods:

We used SYBR Green-based quantitative-PCR to quantify miRNAs expression.

Results:

Our analysis revealed the increased expression levels of miR-21 (p = 0.034), miR-25 (p = 0.0003), miR-93 (p = 0.0406), and miR-106b (p = 0.023) in GC samples. In addition, GC patients with positive lymph node metastasis showed the up-regulation of miR-25, miR-93, and miR-106b (p < 0.05).

Conclusion:

Our findings suggested that the expression of miR-21, miR-25, miR-93, and miR-106b altered in GC, and some of them may be further investigated as biomarkers for GC early detection and prognosis prediction.

MiR-152-5p as a microRNA passenger strand special functions in human gastric cancer cells

Gastric cancer (GC) is one of the most common malignancies with high mortality rate. MiR-152 may exert the function of tumor suppressor by regulating its target gene, including PIK3CA. Nevertheless, all of the described functions are referred explicitly to miR-152-3p, while miR-152-5p as a passenger strand is poorly realized and entirely ignored. We previously selected miR-152-5p as a candidate using cell migration inhibition screening for GC cells and predicted that miR-152-5p might also target PIK3CA. In this study, we found an abnormal proportion of miR-152-3p / miR-152-5p in GC (gastric cancer) tissues and cells and demonstrated that miR-152-5p had poorer stability in GC cells, revealing the possibility that miR-152-5p is abnormally "suppressed" in gastric cancer. We also investigated and confirmed the role of miR-152-5p in GC by a series of experiments, and found that miR-152-5p modulated cell viability, migration, invasion, and cell-cycle progression of human GC cells, and also inhibited tumor growth and metastasis in vivo partially by targeting PIK3CA. More interestingly, it was proved that miR-152-3p and miR-152-5p had synergistic effects on the inhibition of PIK3CA in GC cells. The results of this study suggest that miR-152-5p may act as a tumor suppressor in SGC-7901 gastric cancer cells via targeting PIK3CA. Further, the study provides a novel insight into the roles of miRNA* during carcinogenesis.

Gastric cancer: epidemiology, prevention, classification, and treatment

Gastric cancer is the second most common cause of cancer-related deaths in the world, the epidemiology of which has changed within last decades. A trend of steady decline in gastric cancer incidence rates is the effect of the increased standards of hygiene, conscious nutrition, and Helicobacter pylori eradication, which together constitute primary prevention. Avoidance of gastric cancer remains a priority. However, patients with higher risk should be screened for early detection and chemoprevention. Surgical resection enhanced by standardized lymphadenectomy remains the gold standard in gastric cancer therapy. This review briefly summarizes the most important aspects of gastric cancers, which include epidemiology, risk factors, classification, diagnosis, prevention, and treatment. The paper is mostly addressed to physicians who are interested in updating the state of art concerning gastric carcinoma from easily accessible and credible source.

Identification of miR-758-3p as Potential Modulator of CBX5 Expression in Gastric Cancer

Gastric cancer is one of the most frequently diagnosed cancer types in China and also the leading causes of cancer-related death. Previous study showed chromobox 5 expression was elevated in gastric cancer, but little is known regarding the precise molecular mechanisms by which chromobox 5 expression was modulated. In this study, we revealed that chromobox 5 could promote gastric cancer cell proliferation, migration, and invasion in vitro. We screened and identified microRNA-758-3p, whose expression was downregulated in gastric cancer tissues and cell lines, which was a potential upstream molecule of chromobox 5. Upregulation of microRNA-758-3p could markedly downregulate the expression of chromobox 5. Additionally, expression of microRNA-758-3p and chromobox 5 was inversely correlated in gastric cancer tissues. Moreover, microRNA-758-3p overexpression suppressed gastric cancer cell proliferation, migration, and invasion, but these effects can be partially reversed by chromobox 5 overexpression. Collectively, our results indicate that microRNA-758-3p serves as a tumor suppressor and plays a crucial role in inhibiting the proliferation, migration, and invasion of gastric cancer via targeting chromobox 5 and implicate its potential application in cancer therapy.

High expression of eIF3d is associated with poor prognosis in patients with gastric cancer

Background

Eukaryotic initiation factor 3 subunit d (eIF3d) is the largest subunit of eIF3, which is shown to promote protein synthesis in cancer cells. Increased expression of eIF3d has been shown in some types of cancers, but has not been previously studied in gastric cancer (GC). Thus, the aim of this study was to analyze eIF3d expression in GC.

Patients and methods

Expression of eIF3d was detected by immunohistochemistry in GC tissues and adjacent noncancerous (ANC) tissues. Samples were obtained from 210 patients with GC who had received curative gastrectomy. Clinicopathological features and survival rate were also analyzed.

Results

Expression rates of eIF3d in GC and ANC were 45.2% and 21.0%, respectively. High expression of eIF3d protein was significantly related to tumor stage, as determined by lymph node metastasis and depth of invasion (p<0.05). The Kaplan–Meier survival curves showed that patients with high eIF3d expression had a significantly poor overall survival (p=0.005). Multivariate Cox regression analyses showed that the level of eIF3d was an independent predictive factor of poor prognosis for GC (p=0.017).

Conclusion

Expression of eIF3d was upregulated in GC. High expression of eIF3d was determined as an independent poor prognostic factor in GC. It is suggested that eIF3d could be a good biomarker in GC.

High Intratumoral Expression of Tetranectin Associates with Poor Prognosis of Patients with Gastric Cancer after Gastrectomy

Tetranectin, encoded by the clec3b gene, is a plasminogen kringle-4 binding protein that can be detected in the plasma and the extracellular matrix. In malignancies, tetranectin is thought to enhance proteolytic processes enabling tumor cells to invade and metastasize. Nevertheless, the prognostic value of tetranectin in gastric cancer remains elusive. In this study, we found the expression of tetranectin was decreased in gastric cancer. High intratumoral tetranectin level was positively associated with tumor invasion (P = 0.013), lymph node metastasis (P = 0.005), advanced TNM stage (P = 0.003) and shorter overall survival (OS) (P < 0.001) for patients with gastric cancer. Tetranectin expression was identified as an independent prognostic factor for poor OS, and combining tetranectin expression with other independent prognostic factors generated a predictive nomogram, which showed better prognostic efficiency for OS in patients with gastric cancer. In summary, our study suggests that intratumoral tetranectin is a potential independent unfavorable prognostic biomarker for OS of patients with gastric cancer after gastrectomy.

MiR-646 inhibited cell proliferation and EMT-induced metastasis by targeting FOXK1 in gastric cancer

Background:

MiR-646 has been reported to be aberrantly expressed in human cancers. However, the underlying molecular mechanisms of action of miR-646 in gastric cancer (GC) have not yet been investigated.

Methods:

In vitro function of miR-646 in GC was evaluated using EdU assay, plate colony formation assay, and matrigel invasion assay. Real-time PCR or western blotting was performed to detect miR-646 and FOXK1 expressions. In vivo tumour growth and metastasis were conducted in nude mice.

Results:

MiR-646 expression was downregulated in GC tissues compared with adjacent normal tissues. Low miR-646 expression is associated with malignant progression. Transient transfection of GC cells with miR-646 inhibited their growth and migration. Moreover, miR-646 influenced the expression of epithelial–mesenchymal transition (EMT)-associated proteins. TGF-β1 treatment significantly suppressed the expression of miR-646 and overexpression of this microRNA counteracted the influence of the TGF-β1-induced EMT phenotype. In terms of the underlying mechanism, miR-646 directly targeted FOXK1. In vivo, it inhibited the FOXK1-mediated proliferation and EMT-induced metastasis. Consistently, inverse correlations were also observed between the expression of miR-646 and FOXK1 in human GC tissue samples. Furthermore, miR-646 regulated Akt/mTOR signalling after FOXK1.

Conclusions:

miR-646 inhibited GC cell proliferation and the EMT progression in GC cells by targeting FOXK1.

A Downmodulated MicroRNA Profiling in Patients with Gastric Cancer

Objective. Here, we aim to investigate the microRNA (miR) profiling in human gastric cancer (GC). Methods. Tumoral and matched peritumoral gastric specimens were collected from 12 GC patients who underwent routine surgery. A high-throughput miR sequencing method was applied to detect the aberrantly expressed miRs in a subset of 6 paired samples. The stem-loop quantitative real-time polymerase chain reaction (qRT-PCR) assay was subsequently performed to confirm the sequencing results in the remaining 6 paired samples. The profiling results were also validated in vitro in three human GC cell lines (BGC-823, MGC-803, and GTL-16) and a normal gastric epithelial cell line (GES-1). Results. The miR sequencing approach detected 5 differentially expressed miRs, hsa-miR-132-3p, hsa-miR-155-5p, hsa-miR-19b-3p, hsa-miR-204-5p, and hsa-miR-30a-3p, which were significantly downmodulated between the tumoral and peritumoral GC tissues. Most of the results were further confirmed by qRT-PCR, while no change was observed for hsa-miR-30a-3p. The in vitro finding also agreed with the results of both miR sequencing and qRT-PCR for hsa-miR-204-5p, hsa-miR-155-5p, and hsa-miR-132-3p. Conclusion. Together, our findings may serve to identify new molecular alterations as well as to enrich the miR profiling in human GC.

Elevated Expression of Calpain-4 Predicts Poor Prognosis in Patients with Gastric Cancer after Gastrectomy

Calpain-4 belongs to the calpain family of calcium-dependent cysteine proteases, and functions as a small regulatory subunit of the calpains. Recent evidence indicates that calpain-4 plays critical roles in tumor migration and invasion. However, the roles of calpain-4 in gastric tumorigenesis remain poorly understood. Herein, we examined calpain-4 expression by immunohistochemical staining on tissue microarrays containing tumor samples of 174 gastric cancer patients between 2004 and 2008 at a single center. The Kaplan-Meier method was used to compare survival curves, and expression levels were correlated to clinicopathological factors and overall survival. Our data demonstrated that calpain-4 was generally increased in gastric cancer cell lines and primary tumor tissues. High expression of calpain-4 was positively associated with vessel invasion, lymph node metastasis, and advanced TNM (Tumor Node Metastasis) stage. Multivariate analysis identified calpain-4 as an independent prognostic factor for poor prognosis. A predictive nomogram integrating calpain-4 expression with other independent prognosticators was constructed, which generated a better prognostic value for overall survival of gastric cancer patients than a TNM staging system. In conclusion, calpain-4 could be regarded as a potential prognosis indicator for clinical outcomes in gastric cancer.

Overexpression of p42.3 promotes cell proliferation, migration, and invasion in human gastric cancer cells

As a newly discovered tumor-specific gene, p42.3 is overexpressed in most of human gastric cancers (GC). However, the role of p42.3 in GC progression remains unclear. To assess the role of p42.3 in gastric cancers, immunohistochemistry and western blot were performed to detect the p42.3 expression in human GC tissues and cells. We also investigated the role of p42.3 in GC cell proliferation, migration, and invasion. Our results showed that the p42.3 expression was increased dramatically in human GC tissue and cells. In addition, we found that overexpression of p42.3 promotes GC cell proliferation, migration, and invasion abilities. Furthermore, p42.3 expression suppressed the E-cadherin protein level and promoted the β-catenin and p-ERK protein level. Taken together, overexpressed p42.3 is correlated with gastric cancer cell proliferation, migration, and invasion, suggesting its use as a biological marker in gastric cancer.

Molecular classification of gastric cancer: Towards a pathway-driven targeted therapy

Gastric cancer (GC) is the third leading cause of cancer mortality worldwide. Although surgical resection is a potentially curative approach for localized cases of GC, most cases of GC are diagnosed in an advanced, non-curable stage and the response to traditional chemotherapy is limited. Fortunately, recent advances in our understanding of the molecular mechanisms that mediate GC hold great promise for the development of more effective treatment strategies. In this review, an overview of the morphological classification, current treatment approaches, and molecular alterations that have been characterized for GC are provided. In particular, the most recent molecular classification of GC and alterations identified in relevant signaling pathways, including ErbB, VEGF, PI3K/AKT/mTOR, and HGF/MET signaling pathways, are described, as well as inhibitors of these pathways. An overview of the completed and active clinical trials related to these signaling pathways are also summarized. Finally, insights regarding emerging stem cell pathways are described, and may provide additional novel markers for the development of therapeutic agents against GC. The development of more effective agents and the identification of biomarkers that can be used for the diagnosis, prognosis, and individualized therapy for GC patients, have the potential to improve the efficacy, safety, and cost-effectiveness for GC treatments.

Decreased expression of Calpain-9 predicts unfavorable prognosis in patients with gastric cancer

Calpain-8 and calpain-9 belong to the family of calcium-dependent cysteine proteases, which are highly expressed in the stomach. However, the roles of calpain-8 and calpain-9 in gastric tumorigenesis remain little understood. Herein, we demonstrated that calpain-9 was generally decreased in gastric cancer cell lines and primary tumor tissues, while calpain-8 expression was not significantly altered. Calpain-9, but not calpain-8, induced cell cycle arrest in the G1 phase and cellular apoptosis in vitro, and it attenuated the growth of subcutaneous tumor xenografts in vivo. Low expression of calpain-9 was positively associated with male sex, late T stage, lymph node metastasis, and advanced TNM stage. Further analysis identified calpain-9 as an independent prognostic factor for poor prognosis, and combining calpain-9 with TNM stage generated a better predictive model for patient outcomes. In conclusion, calpain-9 is a tumor suppressor that can be regarded as a potential prognosis indicator for clinical outcomes in gastric cancer.

Mouse models for gastric cancer: Matching models to biological questions

Gastric cancer is the third leading cause of cancer-related mortality worldwide. This is in part due to the asymptomatic nature of the disease, which often results in late-stage diagnosis, at which point there are limited treatment options. Even when treated successfully, gastric cancer patients have a high risk of tumor recurrence and acquired drug resistance. It is vital to gain a better understanding of the molecular mechanisms underlying gastric cancer pathogenesis to facilitate the design of new-targeted therapies that may improve patient survival. A number of chemically and genetically engineered mouse models of gastric cancer have provided significant insight into the contribution of genetic and environmental factors to disease onset and progression. This review outlines the strengths and limitations of current mouse models of gastric cancer and their relevance to the pre-clinical development of new therapeutics.

Endogenous molecular network reveals two mechanisms of heterogeneity within gastric cancer

Intratumor heterogeneity is a common phenomenon and impedes cancer therapy and research. Gastric cancer (GC) cells have generally been classified into two heterogeneous cellular phenotypes, the gastric and intestinal types, yet the mechanisms of maintaining two phenotypes and controlling phenotypic transition are largely unknown. A qualitative systematic framework, the endogenous molecular network hypothesis, has recently been proposed to understand cancer genesis and progression. Here, a minimal network corresponding to such framework was found for GC and was quantified via a stochastic nonlinear dynamical system. We then further extended the framework to address the important question of intratumor heterogeneity quantitatively. The working network characterized main known features of normal gastric epithelial and GC cell phenotypes. Our results demonstrated that four positive feedback loops in the network are critical for GC cell phenotypes. Moreover, two mechanisms that contribute to GC cell heterogeneity were identified: particular positive feedback loops are responsible for the maintenance of intestinal and gastric phenotypes; GC cell progression routes that were revealed by the dynamical behaviors of individual key components are heterogeneous. In this work, we constructed an endogenous molecular network of GC that can be expanded in the future and would broaden the known mechanisms of intratumor heterogeneity.

Decreased expression of Siglec-8 associates with poor prognosis in patients with gastric cancer after surgical resection

The expression of sialic acid-binding Ig-like lectin (Siglec) family has been detected in many malignant tumors and correlated with patient outcomes. The present study aims to investigate the prognostic value of Siglec-8 expression and refine current risk stratification system in patients with gastric cancer. Two independent sets of patients (n = 78; n = 356, respectively) with gastric cancer from Zhongshan Hospital were enrolled into this study. The expression of Siglec-8 was detected by immunohistochemistry. Cox regression analysis was used to assess the prognostic value of Siglec-8 expression and clinical outcomes. A novel molecular prognostic stratification system combining intratumoral Siglec-8 expression with TNM stage was determined by means of receiver operating characteristic analysis. Multivariate Cox regression analysis identified that intratumoral Siglec-8 low expression was an independent prognostic factor for dismal overall survival of patients with gastric cancer. Incorporating intratumoral Siglec-8 expression into the current TNM staging system showed more accuracy for predicting prognosis of patients with gastric cancer. Our study suggested that intratumoral Siglec-8 expression was an independent prognostic factor for overall survival of patients with gastric cancer. Incorporating Siglec-8 expression level into current TNM staging system might add more comprehensive prognostic information for patients with gastric cancer and lead to a more precise risk stratification system for predicting clinical outcomes.

Upregulated long intergenic noncoding RNA KRT18P55 acts as a novel biomarker for the progression of intestinal-type gastric cancer

Background

Long noncoding RNAs (lncRNAs) with dysregulated expression levels have been investigated in numerous types of different cancer. Whether lncRNAs can predict the progression of gastric cancer (GC) still remains largely unclear. The aim of our study was to investigate whether KRT18P55, a novel intergenic lncRNA, can be a predictive biomarker for GC.

Methods

To determine the expression levels of KRT18P55 in GC, we evaluated it in five GC cell lines (SGC-7901, MGC-803, BGC-823, AGS, and HG27) and 97 GC tissue samples in comparison with a normal control by quantitative polymerase chain reaction. In addition, the association with patient clinicopathological characteristics was analyzed to identify the clinical significance of KRT18P55. We also used publicly accessible data from The Cancer Genome Atlas (TCGA) to further verify the expression levels and clinical significance of KRT18P55. Furthermore, a receiver operating characteristic curve was also conducted to evaluate the diagnostic value of KRT18P55 for GC.

Results

A significant upregulation was observed in GC cell lines (P<0.01) and tissue samples (P<0.01). This finding was consistent with the results of 29 pairs of GC tissue samples from TCGA (P<0.01). Additionally, we indicated that the increased expression of KRT18P55 was related to the progression of intestinal type (P=0.032), which was also supported by results of independent GC cohorts from TCGA (P<0.01). However, we did not find significant difference in prognosis between patients with high and low expression of KRT18P55 (P>0.05). Finally, KRT18P55 showed potential diagnostic value for GC with an area under the receiver operating characteristic curve of 0.733 (P<0.01).

Conclusion

Upregulated KRT18P55 was a novel biomarker for the progression of GC, especially for the intestinal type.

The prognostic value of CXC-chemokine receptor 2 (CXCR2) in gastric cancer patients

Background

CXC chemokine receptor 2 (CXCR2) has been reported to play an important role in the proliferation and invasion of gastric cancer cells. The present study aims to investigate the impact of CXCR2 expression on the overall survival (OS) of gastric cancer patients after radical resection.

Methods

Intratumoral CXCR2 expression was evaluated with immunohistochemistry on tissue microarrays containing tumor samples of 357 gastric cancer patients from a single center. CXCR2 expression levels were correlated to clinicopathological variables and OS.

Results

CXCR2 expression was mainly located in the cytoplasm of gastric carcinoma cells. High CXCR2 expression was associated with poor tumor differentiation (p = 0.021), increased tumor depth (p < 0.001), lymph node metastasis (p < 0.001), advanced TNM stage (p < 0.001) and short OS (p = 0.001). CXCR2 expression was an independent prognostic factor for OS (p = 0.001) in multivariate analysis, and could be combined with TNM stage to generate a predictive nomogram for clinical outcome in patients with gastric cancer.

Conclusion

Intratumoral CXCR2 expression is a novel independent predictor for survival in gastric cancer patients. CXCR2 might be a promising therapeutic target of postoperative adjuvant treatment.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-015-1793-9) contains supplementary material, which is available to authorized users.

Roles of competing endogenous RNAs in gastric cancer

Long noncoding RNA (lncRNA) is >200 nucleotides long and lacks coding ability. LncRNA was regarded as transcript noise, until emerging results showed its roles in development, homeostasis and carcinogenesis. LncRNAs containing microRNA (miRNA) response elements could compete with the miRNA target gene and regulate its expression through decreasing free functional miRNA. Such lncRNA is called competing endogenous RNA (ceRNA), and the 'lncRNA-miRNA' interaction appreciably enriches the world of RNA-RNA regulation. Gastric cancer involves dysregulation of both protein-coding genes and noncoding genes, and the ceRNA regulatory mechanism may participate in this pathogenic process. In this review, we discuss recent findings on the roles of ceRNAs in gastric carcinogenesis.

Liver receptor homolog-1 (LRH-1): a potential therapeutic target for cancer

Liver receptor homolog-1 (LRH-1) is a nuclear receptor involved in various biological processes. This nuclear receptor has critical functions in embryonic development as well as in adult homeostasis. Although the physiological functions of LRH-1 in normal breast, pancreas, and intestine have been widely investigated, the dysregulation that occurs during pathological conditions is not well understood. LRH-1 has been implicated in pancreatic, breast, and gastrointestinal cancer, where it exerts its effect of initiation and progression by promoting cell proliferation and metastasis. In addition to mechanistic studies, LRH-1 agonists and antagonists are being explored. Identification and development of endogenous and synthetic ligands has been pursued using computational-based structural analysis. Through ligand identification and a thorough understanding of the pathological roles of LRH-1, new therapeutic avenues for cancer treatment based upon LRH-1 may be a desirable focus for further research.

Diagnostic and prognostic significance of glypican 5 and glypican 6 gene expression levels in gastric adenocarcinoma

Gastric Cancer is one of the most common malignancies worldwide and the second most common cause of cancer-related mortality. Previous studies revealed several genetic alterations specific to gastric cancer. In this study, we aimed to investigate the diagnostic and prognostic significance of the expression levels of the glypican 5 and glypican 6 genes (GPC5 and GPC6, respectively) in gastric cancer. For this purpose, GPC5 and GPC6 expression was quantitatively determined by quantitative polymerase chain reaction method in normal gastric mucosa and intestinal type gastric adenocarcinoma samples from 35 patients. The expression levels of GPC5 and GPC6 were compared between normal and tumor tissues. Additionally, the association of the expression levels in tumor tissues with several clinicopathological parameters was evaluated. Although GPC5 was not expressed in any of the samples, the expression of GPC6, which was detected in both groups, was found to be significantly higher in tumor tissues compared to that in normal samples (P=0.039). However, there was no statistically significant association between GPC6 expression and any of the clinicopathological parameters investigated (P>0.05). Our findings suggested that an increase in GPC6 expression levels may be implicated in gastric cancer development, but not in cancer progression.

Long noncoding RNAs: novel insights into gastric cancer

Long non-coding RNAs (lncRNAs) are functional RNAs longer than 200 nucleotides. Recent advances in the non-protein coding part of human genome analysis have discovered extensive transcription of large RNA transcripts that lack coding protein function, termed non-coding RNA (ncRNA). It is becoming evident that lncRNAs may be an important class of pervasive genes involved in carcinogenesis and metastasis. However, the biological and molecular mechanisms of lncRNAs in diverse diseases are not yet fully understood. Thus, it is anticipated that more efforts should be made to clarify the lncRNA world. Moreover, accumulating evidence has demonstrated that many lncRNAs are dysregulated in gastric cancer (GC) and closely related to tumorigenesis, metastasis, and prognosis or diagnosis. In this review, we will briefly outline the regulation and functional role of lncRNAs in GC. Finally, we discussed the potential of lncRNAs as prospective novel targets in GC treatment and biomarkers for GC diagnosis.

Prognostic value of stromal cell-derived factor 1 expression in patients with gastric cancer after surgical resection

Aberrant chemokine stromal cell-derived factor 1 (SDF-1) expression has been shown to be involved in the development and progression of various malignancies. Our present study aims to investigate the clinical and prognostic value of SDF-1 expression and improve risk stratification in patients with gastric cancer. Peritumoral and intratumoral SDF-1 levels were assessed in 220 retrospectively enrolled gastric cancer patients, and their relations with clinicopathological features and clinical outcomes were evaluated. A predictive nomogram was created to refine risk stratification for overall survival of gastric cancer patients. Compared with peritumor tissues, tumor tissues showed decreased SDF-1 expression levels according to TNM stage progression in gastric cancer specimens. Peritumoral SDF-1 expression correlated positively with tumor invasion depth and lymph node metastasis, whereas intratumoral SDF-1 expression associated negatively with tumor size, tumor differentiation, tumor invasion depth, lymph node metastasis, and clinical TNM stage. Moreover, both low peritumoral SDF-1 expression and high intratumoral SDF-1 expression indicated favorable overall survival, and SDF-1 risk derived from the peritumoral/intratumoral SDF-1 expression signature could stratify prognosis of patients with gastric cancer. After backward elimination, SDF-1 risk was identified as an independent prognostic factor for survival. Finally, a predictive nomogram was generated with identified independent prognosticators to assess patient survival at 3 and 5 years following surgery. Conclusively, SDF-1 risk, an identified independent prognostic factor, could be developed into a nomogram with tumor invasion depth, lymph node involvement, and distant metastasis to refine predictive accuracy for survival in patients with gastric cancer after surgical resection.