Treatment strategies in gastric cancer

Lifestyle factors on the long-term survival of gastric cancer patients after radical resection: A cohort study

Background

This retrospective cohort study aimed to evaluate the effect of lifestyle factors (e.g., smoking, drinking, physical exercise, and sleep duration) on the long-term survival of gastric cancer (GC) patients after radical resection.

Materials and Methods

GC patients after radical resection were enrolled from January 2016 to December 2017. Their baseline clinical data, lifestyle factors, and prognosis were collected. The primary endpoint was all-cause death. The relationship between the variables and survival was examined using the Cox proportional hazards model.

Results

A total of 309 patients were enrolled and 296 patients were followed up for a median of 54.0 months, with 130 confirmed deaths. Older age (>60 years) (hazard ratio [HR]: 1.307, 95% confidence interval [CI]: 1.056-2.161, P = 0.006), advanced tumor, node, and metastasis stage (P < 0.05), poorly pathological differentiation (HR: 1.765, 95% CI: 1.080-2.884, P = 0.023), history of smoking (P < 0.001), never physical exercise (HR: 2.057, 95% CI: 1.170-3.617, P = 0.012), long sleep duration (≥8 h) (HR: 4.160, 95% CI: 1.501-11.533, P = 0.006), and short sleep duration (<6 h) (HR: 3.417, 95% CI: 1.312-8.900, P = 0.012) were independent indicators of a poor overall survival in GC patients after radical resection.

Conclusion

Smoking cessation, proper sleep duration, and regular physical exercise habits can improve the long-term survival of GC patients after radical resection.

The Bile Acid Membrane Receptor TGR5 in Cancer: Friend or Foe?

The G-protein-coupled bile acid receptor, Gpbar1 or TGR5, is characterized as a membrane receptor specifically activated by bile acids. A series of evidence shows that TGR5 induces protein kinase B (AKT), nuclear factor kappa-B (NF-κB), extracellular regulated protein kinases (ERK1/2), signal transducer and activator of transcription 3 (STAT3), cyclic adenosine monophosphate (cAMP), Ras homolog family member A (RhoA), exchange protein activated by cAMP (Epac), and transient receptor potential ankyrin subtype 1 protein (TRPA1) signaling pathways, thereby regulating proliferation, inflammation, adhesion, migration, insulin release, muscle relaxation, and cancer development. TGR5 is widely distributed in the brain, lung, heart, liver, spleen, pancreas, kidney, stomach, jejunum, ileum, colon, brown adipose tissue (BAT), white adipose tissue (WAT), and skeletal muscle. Several recent studies have demonstrated that TGR5 exerts inconsistent effects in different cancer cells upon activating via TGR5 agonists, such as INT-777, ursodeoxycholic acid (UDCA), and taurolithocholic acid (TLCA). In this review, we discuss both the ‘friend’ and ‘foe’ features of TGR5 by summarizing its tumor-suppressing and oncogenic functions and mechanisms.

Aberrant ARMCX1 Expression Is an Independent Predictor of Poor Prognosis in Gastric Cancer

ARMCX1 (Armadillo repeat containing X-linked 1) is identified to be the novel tumor suppressor gene related to multiple tumor types. Nonetheless, its effect on gastric cancer (GC) is still poorly understood. The present work determined ARMCX1 level within GC and the relation with clinicopathological characteristics. This work also collected relevant information in The Cancer Genome Atlas (TCGA) database for investigating associations of ARMCX1 with clinicopathologic variables and then validated in our GC cohort. Receiver operating characteristic (ROC) curves were plotted for assessing whether ARMCX1 expression was significant in diagnosing GC. Kaplan-Meier (KM) and Cox regression analyses were conducted for assessing clinicopathological characteristics associated with overall survival (OS) of GC cases. The data from the Human Protein Atlas (HPA) and Gene Expression Omnibus (GEO) databases was also analyzed for further validation, and biological processes (BPs) were identified by gene set enrichment analysis (GSEA). GC tissues showed markedly decreased ARMCX1 level relative to healthy counterparts (P < 0.001). Interestingly, ARMCX1 upregulation predicted low differentiation, poor OS, increased invasion, and late tumor stage. In addition, the area under ROC curve (AUC) and P value were 0.747 and <0.001, separately. Cases showing ARMCX1 upregulation showed significantly poor prognostic outcome compared with patients showing downregulation (P = 0.007). Furthermore, multivariate analysis showed that ARMCX1 upregulation independently predicted the risk of OS (P = 0.0017, hazard ratio, 1.089). GSEA analysis identified that several cancer-related pathways, such as focal adhesion, ECM receptor interaction, JAK/STAT, melanoma, WNT, and cancer, were enriched in GCs. We conclude that ARMCX1 serves as the possibly independent biomarker to diagnose and predict GC prognostic outcome.

Effects of an oral elemental nutritional supplement in gastric cancer patients with adjuvant S-1 chemotherapy after gastrectomy: A multicenter, open-label, single-arm, prospective phase II study (OGSG1108)

AIM

Post-surgical weight loss influences chemotherapy compliance and may be a risk factor for survival. Intake of an oral elemental nutritional supplement (OENS) can reduce weight loss after gastric cancer (GC) surgery. We assessed whether therapy completion levels would increase in patients receiving postoperative adjuvant chemotherapy in combination with an OENS.

METHODS

This was a multicenter, open-label, single-arm, phase II study in GC patients who underwent curative total or distal gastrectomy (TG/DG) and received adjuvant S-1 chemotherapy. The primary endpoint was the S-1 completion rate for 1 year with a relative performance (RP) value of ≥70%; secondary endpoints included factors affecting the completion rate of S-1, RP value after eight S-1 courses, S-1 and OENS persistence rates, nutritional index, OENS compliance, and safety.

RESULTS

In 71 efficacy-evaluable patients, the S-1 completion rate was 69.0% (TG, 68.0%; DG, 69.6%) and the RP value was 87.5 (TG, 89.1; DG, 87.5). Over eight treatment courses, median persistence rates were 89.0% for S-1 and 93.8% for the OENS. The mean OENS compliance was 81.8% at the fourth S-1 course and 52.9% at the eighth course. The incidence of Grade 3 or 4 adverse events was 27.2%, most commonly neutropenia (12.3%).

CONCLUSIONS

The completion rate of S-1 for 1 year in patients who could take the OENS exceeded the pre-defined threshold level. Randomized controlled trials are warranted to confirm the role of OENS in adjuvant chemotherapy.

Clinicopathological and prognostic significance of programmed death ligant-1 expression in gastric cancer: a meta-analysis

Background

Gastric cancer (GC) is a common malignant tumor with a high incidence in China. The use of immune checkpoint inhibitors has become the focus of tumor immunotherapy in recent years. This study was to investigate the clinicopathological and prognostic significance of programmed death ligant-1 (PD-L1) expression in GC.

Methods

We searched the PubMed, ScienceNet, EMbase, CNKI, and Wanfang databases for retrospective cohort studies on the clinicopathology and prognosis of PD-L1 expression in GC published between January 2010 and April 2020. The literature was first selected to extract data according to the inclusion and exclusion criteria, then a meta-analysis performed using Stata15.0 software. Publication bias and sensitivity analysis were carried out for the included studies.

Results

A total of 3,218 patients in 15 studies were included in the meta-analysis. The positive expression of PD-L1 was related to a decrease in the 3-year survival rate (HR =1.32, 95% CI: 1.02-1.49, P=0.028) and 5-year survival rate (HR =1.39, 95% CI: 1.14-1.69, P=0.001). The difference in PD-L1 expression was related to lymph node metastasis (OR =1.73, 95% CI: 1.18-2.54, P<0.001), but not to tumor stage (OR =1.28, 95% CI: 0.81-2.02, P=0.292).

Conclusions

The results show that PD-L1 is related to the prognosis of GC. Its high expression decreases the 3- and 5-year survival rates and promotes lymph node metastasis, but does not reflect tumor stage. The results may provide a theoretical basis for the choice of clinical immunotherapy in GC patients.

PD-L1 gene promoter methylation represents a potential diagnostic marker in advanced gastric cancer

Gastric cancer is one of the most prevalent malignant tumors worldwide. Immunological checkpoint inhibitors of the programmed death 1 (PD-1)/programmed cell death-ligand 1 (PD-L1) signaling pathway are effective in the treatment of various malignant tumor types, but the potential of such immunotherapeutic techniques for the treatment of gastric cancer is yet to be elucidated. The purpose of the present study was to investigate the methylation of the PD-L1 gene promoter and its clinical significance in advanced gastric cancer, as this may suggest the use of PD-L1 promoter methylation as a novel biomarker for gastric cancer progression. In a total of 70 samples, the methylation rate of the PD-L1 gene promoter region was significantly higher in gastric cancer tissues compared with adjacent tissues. A high level of PD-L1 promoter methylation was associated with lymph node staging, and resulted in poorer prognoses in patients with advanced gastric cancer. A total of 26 patients exhibited highly methylated PD-L1; in this group, the median progression-free survival time of patients receiving platinum/fluorouracil chemotherapy was 4.2 months longer than those receiving paclitaxel/fluorouracil chemotherapy, and the risk of disease progression in patients receiving paclitaxel/fluorouracil chemotherapy was 5.009 times higher compared with patients who received platinum/fluorouracil chemotherapy. Additionally, PD-L1 promoter methylation was significantly correlated with PD-L1 expression, and the progression of advanced gastric cancer. In conclusion, high methylation levels of the PD-L1 promoter region may be a faciliatory mechanism enabling gastric cancer tumorigenesis, and may also represent an independent prognostic factor for chemotherapeutic efficacy in patients with advanced gastric cancer.

The Role of the Small Bowel in Unintentional Weight Loss after Treatment of Upper Gastrointestinal Cancers

Upper gastrointestinal (GI) cancers are responsible for significant mortality and morbidity worldwide. To date, most of the studies focused on the treatments’ efficacy and post-treatment survival rate. As treatments improve, more patients survive long term, and thus the accompanying complications including unintentional weight loss are becoming more important. Unintentional weight loss is defined as >5% of body weight loss within 6–12 months. Malignancies, particularly GI cancers, are diagnosed in approximately 25% of patients who present with unintentional weight loss. Whereas some recent studies discuss pathophysiological mechanisms and new promising therapies of cancer cachexia, there is a lack of studies regarding the underlying mechanism of unintentional weight loss in patients who are tumor free and where cancer cachexia has been excluded. The small bowel is a central hub in metabolic regulation, energy homeostasis, and body weight control throughout the microbiota-gut-brain axis. In this narrative review article, the authors discussed the impacts of upper GI cancers’ treatment modalities on the small bowel which may lead to unintentional weight loss and some new promising therapeutic agents to treat unintentional weight loss in long term survivors after upper GI operations with curative intent.

ANXA2 Silencing Inhibits Proliferation, Invasion, and Migration in Gastric Cancer Cells

Annexin A2 (ANXA2) has been well known to associate with the progress of malignant tumor. However, the biological behavior of ANXA2 in gastric cancer (GC) remains unclear. We made a hypothesis in transcriptome level from TCGA datasets. Then, we used immunohistochemical staining to quantify the expression level of ANXA2 protein in GC tissues compared with adjacent tissues. Quantitative real-time PCR and western blot were used for analyzing ANXA2 expression in human GC (SGC-7901, MKN-45, BGC-823, and AGS) cell lines. We investigated the effect of a lentivirus-mediated knock-down of ANXA2 on the proliferation, invasion and migration of gastric cancer AGS cells. Cell proliferation was examined by MTT and colony formation tests. Cell apoptosis and cycle were measured by flow cytometry. Migration and invasion were detected by transwell assay. We found that high expression of ANXA2 can increase the mobility of cancer cells from TCGA datasets. ANXA2 was upregulated in GC tissues compared with adjacent tissues. AGS cell line displayed significantly higher expression of ANXA2 among the four GC cell lines. In addition, ANXA2 silencing led to a weakened ability of proliferation, invasion, and migration in GC cells; targeting of ANXA2 may be a potential therapeutic strategy for GC patients.

Downregulation of microRNA-142-3p and its tumor suppressor role in gastric cancer

An increasing number of studies indicate that microRNAs (miRNAs) may exert an oncogenic or tumor suppressive role in diverse types of cancer. MicroRNA (miR)-142-3p has been detected to be downregulated in a number of cancer types, and it may function as a tumor suppressor. However, the expression profile and potential role of miR-142-3p in gastric cancer remain unknown. In the present study, the expression of miR-142-3p in numerous gastric cancer samples was investigated. It was observed that miR-142-3p was markedly downregulated in cancer tissues compared with normal tissues. Furthermore, a low expression level of miR-142-3p was associated with higher tumor stages. The overexpression of miR-142-3p was able to inhibit the proliferation, invasion and migration of gastric cancer cells. A further investigation into the mechanism underlying the effect of miR-142-3p identified cyclin T2 (CCNT2) as a target of miR-142-3p in gastric cancers. miR-142-3p may exert its tumor suppressor role partially by downregulating CCNT2. These results suggested that the abnormal downregulation of miR-142-3p and the subsequent increase in CCNT2 expression may have an important role in gastric cancer carcinogenesis.

Polish Consensus on Treatment of Gastric Cancer; update 2017

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

MicroRNA-154 inhibits the growth and metastasis of gastric cancer cells by directly targeting MTDH

MicroRNAs (miRNAs) are a group of non-protein-coding, highly conserved single-stranded RNA molecules. The abnormal expression of miRNAs has been demonstrated to have an important function in the carcinogenesis and progression of gastric cancer. microRNA-154 (miR-154) has been reported to be downregulated in non-small cell lung, colorectal and prostate cancer. However, the expression and roles of miR-154 in gastric cancer remain to be established. The present study measured the expression levels of miR-154 in gastric cancer tissues and cell lines. miR-154 was found to be significantly downregulated in gastric cancer tissues and cell lines. In addition, functional studies indicated that the overexpression of miR-154 inhibited the proliferation, migration and invasion of gastric cancer cells. Using TargetScan, a dual luciferase reporter assay, reverse transcription-quantitative polymerase chain reaction and western blot analysis, metadherin (MTDH) was revealed as a novel miR-154 target. In addition, knocking down MTDH lead to a similar effect as overexpressing-154 in gastric cells. The present findings indicate that miR-154 was downregulated in gastric cancer, and inhibited tumor behaviors of gastric cancer cells partially through the downregulation of MTDH. Therefore, the miR-154/MTDH axis may be a novel therapeutic to treat patients with gastric cancer.

Gastric cancer-derived heat shock protein-gp96 peptide complex enhances dendritic cell activation

AIM

To investigate the role of heat shock protein (HSP)-glycoprotein (gp)96 in dendritic cells (DCs) and lymphocytes induction in gastric cancer (GC).

METHODS

Human GC cell lines KATOIII, MKN-28 and SGC-7901 were infected with adenovirus gp96 at a multiplicity of infection of 100. gp96-GC antigen peptide complexes were purified. MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay, lactate dehydrogenase (LDH) release assay and enzyme-linked immunosorbent assay were used to determine allo-reactive T cell stimulation, natural killer (NK) cell activity and expression of cytokines (such as interleukin (IL)-10, IL-12, interferon (IFN)-γ and tumor necrosis factor (TNF)-α), respectively. Effect of cytotoxic T lymphocyte (CTL) on DCs incubated with HSP-gp96 was also evaluated by LDH release. All assays were performed in triplicate and the average values were reported. Comparison between groups was conducted using Student’s t test.

RESULTS

T cells incubated with HSP-gp96 exhibited a marked increase in proliferation in a dose-dependent manner (P < 0.05). NK cell activity after gp96-GC peptide complex treatment was significantly higher than that after antigen peptide treatment (P < 0.05). The activity of CTLs incubated with DCs from three GC cells lines was obviously higher than that stimulated by GC antigen at ratios of 50: 1, 25: 1, 10: 1, and 5: 1 (P < 0.05). Furthermore, the secretion of TNF-α, IL-10, IL-12 (P70) and IFN-γ markedly increased after incubation with HSP-gp96 (P < 0.05).

CONCLUSION

HSP-gp96 promotes T cell response, enhances DC antigen presentation and induces cytokine secretion, as well. HSP-gp96 has potential as immunotherapy for elimination of residual GC cells.

MiR-133b inhibits growth of human gastric cancer cells by silencing pyruvate kinase muscle-splicer polypyrimidine tract-binding protein 1

The metabolism in tumor cells shifts from oxidative phosphorylation to glycolysis even in an aerobic environment. This phenomenon is known as the Warburg effect. This effect is regulated mainly by polypyrimidine tract‐binding protein 1 (PTBP1), which is a splicer of the mRNA for the rate‐limiting enzymes of glycolysis, pyruvate kinase muscle 1 and 2 (PKM1 and PKM2). In the present study, we demonstrated that miR‐133b reduced PTBP1 expression at translational level and that the expression levels of miR‐133b were significantly downregulated in gastric cancer clinical samples and human cell lines, whereas the protein expression level of PTBP1 was upregulated in 80% of the 20 clinical samples of gastric cancer examined. Ectopic expression of miR‐133b and knockdown of PTBP1 in gastric cancer cells inhibited cell proliferation through the induction of autophagy by the switching of PKM isoform expression from PKM2‐dominant to PKM1‐dominant. The growth inhibition was partially canceled by an autophagy inhibitor 3‐MA or a reactive oxygen species scavenger N‐acetylcysteine. These findings indicated that miR‐133b acted as a tumor‐suppressor through negative regulation of the Warburg effect in gastric cancer cells.

Association of FokⅠ polymorphism in vitamin D receptor gene with risk of gastric cancer in a Xinjiang Uygur population

AIM: To investigate whether the FokⅠ polymorphism in the vitamin D receptor gene is associated with risk of gastric cancer.

METHODS: A total of 147 Uygur patients with gastric cancer (group A) were randomly selected from March 2013 to May 2015 in the Tumor Hospital of Xinjiang Medical University, and 151 healthy Uygur people (group B) were used as controls. The FokⅠ polymorphism in the vitamin D receptor gene was determined by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method, followed by an intergroup comparison. By PCR-RFLP test, all the patients with gastric cancer were divided into an FF group (a) and an Ff + ff group (b) according to whether the patient carried the allele f. The D-dimer level of the two groups was then compared.

RESULTS: The frequency of the allele f in gastric cancer patients was higher than that in the control group (57.8% vs 47.4%, P < 0.05). Multivariate logistic regression analysis showed that the study subjects carrying the allele f (Ff + ff) had a higher gastric cancer risk than those without (FF) (OR = 2.85). The D-dimer level in the Ff + ff group was significantly elevated compared with the FF group (2.79 ± 1.21 vs 1.09 ± 0.65, P < 0.05). As the differentiation of gastric cancer worsened, the percentage of patients only carrying the allele F (FF) decreased gradually (P < 0.05).

CONCLUSION: The FokⅠ polymorphism in the vitamin D receptor gene is associated with susceptibility to gastric cancer. The allele f may be one of the risk factors for gastric cancer, whereas the allele F may be a protective factor. Moreover, the levels of D-dimer in patients with gastric cancer carrying the allele f (Ff, ff) are significantly higher than those only carrying the allele F (FF), suggesting that the allele f may be a regulator of D-dimer and thus influences the onset or prognosis of gastric cancer in Uygur people.

Gastric cancer: Current status of lymph node dissection

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

Comparison of Prognostic MicroRNA Biomarkers in Blood and Tissues for Gastric Cancer

Gastric cancer (GC) still keeps up high mortality worldwide with poor prognosis. Efficient and non-invasive prognostic biomarkers are urgently needed. MicroRNAs are non-coding RNAs playing roles in post-transcriptional gene regulation, which contribute to various biological processes such as development, differentiation and carcinogenesis. MicroRNA expression profiles have been associated with the prognosis and outcome in GC. MicroRNA prognostic biomarkers have been identified from blood or tissues samples, but with different prognostic features. Understanding the various roles of microRNAs in different sample sources of GC will provide deep insights into GC progression. In this review, we highlight the distinct prognostic roles of microRNAs biomarkers in blood and tissue according to their relationships with prognostic parameters, survival rates and target pathways. This will be useful for non-invasive biomarker development and selection in prognosis of GC.

Lower expression of PH domain leucine-rich repeat protein phosphatase 1 (PHLPP1) association with poor prognosis of gastric cancer

BACKGROUND

The aim of this study was to investigate the expression of PH domain leucine-rich repeat protein phosphatase 1 (PHLPP1) in gastric cancer (GC), and its potential influence on the prognosis of GC patients.

METHODS

At present study, we examined the immunohistochemical expression of PHLPP1 on tissue microarrays (TMAs) containing 135 gastric adenocarcinoma tissues and 135 matched adjacent non-tumor tissues. In addition, both semi-quantitative reverse transcription polymerase chain reaction (RT-PCR) and western blotting analysis (WB) were adopted to detect of the expression of PHLPP1 in the GC cell lines (AGS, SUN-1, KATO-III, BGC-823, MGC-803, SGC-7901, and HGC-27) and the normal gastric cell line GES-1. Survival analysis was used to investigate the efficiency of the prognostic evaluation of PHLPP1 expression in GC patients.

RESULTS

Positive expression rate of PHLPP1 in the primary GC tissues was significantly lower than that in adjacent non-tumor tissues (55.6% vs. 87.4%, P<0.001). Both gene transcription (mRNA) and Protein expression of PHLPP1 in the GC cell lines were significantly lower than those in the GES-1 cell line, respectively. The Kaplan-Meier analysis showed that patients presented PHLPP1 negative expression in the GC tissues had significantly lower overall survival rate than those presented PHLPP1 positive expression in the GC tissues (P=0.008). With the multivariate survival analysis (Cox regression), PHLPP1 expression in the GC tissue was identified as an independent predictor of the survival of patients.

CONCLUSIONS

This study indicated that aberrant PHLPP1 expression was observed in GC tissues, which was significantly associated with the poor prognostic outcomes of GC patients.

Methylation status of TRAF2 is associated with the diagnosis and prognosis of gastric cancer

The purpose was to investigate whether the expression level of TRAF2 gene was regulated by DNA methylation and explore the role of TRAF2 methylation in the diagnosis and prognosis of gastric cancer (GC). Firstly, we detected the expression of TRAF2 both at mRNA level and protein level. And the up-regulated of TRAF2 expression at two different levels were both found (P<0.001). Then we measured the methylated status of TRAF2 by MSP and got a result of that TRAF2 was hypomethylated in GC patients compared with healthy controls (P<0.001). Meanwhile, the relationship between TRAF2 methylation and clinicopathologic characteristics was estimated through chi-square. The outcome proved that TRAF2 methylation was impacted by age (P=0.024), lymph node metastasis (P=0.046), TNM stage (P=0.021), distant metastasis (P=0.002) and depth of invasion (P=0.002). The AUC of 0.795 accompanying a sensitivity of 66.7% and a specificity of 94.7% were obtained from Receiver Operating Characteristic (ROC) curve which indicated the diagnostic value of TRAF2 methylation was high. At last, we researched the prognostic value of TRAF2 methylation. Kaplan-Meier showed that patients with TRAF2 hypomethylation had lived much shorter than those with TRAF2 hypermethylation (log rank test, P<0.001). Cox regression analysis revealed TRAF2 hypomethylation (HR=18.827, 95% CI=3.103-114.222, P=0.001), lymph node metastasis (HR=0.154, 95% CI=0.047-0.512, P=0.002), distant metastasis (HR=3.032, 95% CI=1.116-8.237, P=0.030), as well as differentiation (HR=0.287, 95% CI=0.113-0.731, P=0.009) were all vital prognostic factors in GC. Taken together, TRAF2 expression was increased in GC patients by DNA hypomethylation and this methylation could be an independent diagnostic and prognostic indicator in GC.

Overexpression of FGFR2 contributes to inherent resistance to MET inhibitors in MET-amplified patient-derived gastric cancer xenografts

Gastric cancer is one of the most malignant diseases and one of the leading causes of cancer-associated mortality worldwide. Although advances have been made in surgical techniques, perioperative management and the combined use of surgery with chemotherapy and/or radiotherapy, patients with advanced stage gastric cancer continue to face poor outcomes. Furthermore, it was reported that MET gene amplification and overexpression predicted the sensitivity to MET inhibitors in gastric cancer. However, the identification of drug-resistant tumors has encouraged the pre-emptive elucidation of the possible mechanisms of clinical resistance. The current study assessed a number of patient-derived gastric cancer models with MET amplification and overexpression, including CNGAS028. The tumor tissues were subjected to microarray analysis (using single nucleotide polymorphism 6.0 and human genome U133 arrays) followed by western blotting. The results demonstrated that CNGAS028 xenograft tumors did not respond to treatment with a selective MET inhibitor. Additional analysis indicated that FGFR2 overexpression contributed to the resistance to MET inhibitors. Furthermore, treatment with a combination of fibroblast growth factor receptor 2 and MET inhibitors inhibited the growth of CNGAS028 xenograft tumors in vivo. In conclusion, the current results aid in understanding the mechanism of inherent resistance to selective MET inhibitors as well as provide important information for patient selection and clinical treatment strategies.

Applicability of the methylated CpG sites of paired box 5 (PAX5) promoter for prediction the prognosis of gastric cancer

Paired box gene 5 (PAX5), a member of the paired box gene family, is involved in control of organ development and tissue differentiation. In previous study, PAX5 promoter methylation was found in gastric cancer (GC) cells and tissues. At present study, we found that the inconsistently methylated levels of PAX5 promoter were identified in the different GC tissues. The methylated CpG site count and the methylated statuses of four CpG sites (-236, -183, -162, and -152) were significantly associated with the survival of 460 GC patients, respectively. Ultimately, the methylated CpG -236 was the optimal prognostic predictor of patients identified by using the Cox regression with AIC value calculation. These findings indicated that the methylated CpG -236 of PAX5 promoter has the potential applicability for clinical evaluation the prognosis of GC.

The survival decrease in gastric cancer is associated with the methylation of B-cell CLL/lymphoma 6 member B promoter

The methylation of B-cell CLL/lymphoma 6 member B (BCL6B) DNA promoter was detected in several malignancies. Here, we quantitatively detect the methylated status of CpG sites of BCL6B DNA promoter of 459 patients with gastric cancer (GC) by using bisulfite gene sequencing. We show that patients with three or more methylated CpG sites in the BCL6B promoter were significantly associated with poor survival. Furthermore, by using the Akaike information criterion value calculation, we show that the methylated count of BCL6B promoter was identified to be the optimal prognostic predictor of GC patients.

Methylation of CpG sites in RNF180 DNA promoter prediction poor survival of gastric cancer

RNF 180, a novel tumor suppressor, has been implicated in the carcinogenesis and progress of gastric cancer. At present study, we found that lower expression of RNA180 was specific in gastric cancer tissues, and the inconsistently methylated levels of RNF180 promoter were identified in the gastric cancer tissues. Importantly, we demonstrated that the methylated CpG site count and four hypermethylated CpG sites (-116, -80, +97, and +102) were significantly associated with the survival of 400 gastric cancer patients, respectively. With multivariate survival analyses, we demonstrated that both the methylation of combined CpG (-116, -80, +97, and +102) sites and N stage were the independent indictor of prognosis of gastric cancer patients. Eventually, the methylation of combined CpG (-116, -80, +97, and +102) sites was identified to have smaller AIC value than N stage by mean of AIC calculation with the Cox proportional hazards model. These findings indicated that the quantitative detection of RNF180 promoter methylation had the intensive feasibility for evaluation the prognosis of gastric cancer patients in clinic.

Cost-effectiveness analysis of adjuvant chemotherapies in patients presenting with gastric cancer after D2 gastrectomy

Background

To analyze and compare the economic outcomes of adjuvant chemotherapy with capecitabine plus oxaliplatin (referred to as the XELOX strategy) and of S-1 (the S-1 strategy) for gastric cancer patients after D2 gastrectomy.

Methods

A Markov model was developed to simulate the lifetime disease course associated with stage II or III gastric cancer after D2 gastrectomy. The lifetime quality-adjusted life years (QALYs), associated costs, and incremental cost-effectiveness ratios (ICERs) were estimated. The clinical data were derived from the results of pilot studies. Direct costs were estimated from the perspective of the Chinese healthcare system, and the utility data were measured from end-point observations of Chinese patients. Sensitivity analyses were used to explore the impact of uncertainty on the model’s outcomes.

Results

The combined adjuvant chemotherapy strategy with XELOX yielded the greatest increase in QALYs over the course of the disease (8.1 QALYs compared with 7.8 QALYs for the S-1 strategy and 6.2 for surgery alone). The incremental cost per QALY gained using the XELOX strategy was significantly lower than that for the S-1 strategy ($3,502 vs. $6,837, respectively). The results were sensitive to the costs of oxaliplatin and the hazard ratio of relapse-free survival.

Conclusion

The observations reported herein suggest that adjuvant therapy with capecitabine plus oxaliplatin is a highly cost-effective strategy and more favorable treatment option than the S-1 strategy in patients with stage II or III gastric cancer who have undergone D2 gastrectomy.

The role of microRNA-133b and its target gene FSCN1 in gastric cancer

Background

Increasing evidences have documented that microRNAs (miRNAs) act as oncogenes or tumor suppressors in gastric cancer (GC). In this study, we aimed to investigate the expression of miR-133b in a large number of GC samples and elucidate its role in GC carcinogenesis and the detailed mechanism.

Methods

We used Taqman probe stem-loop real-time PCR to accurately measure the levels of miR-133b in 100 pairs of gastric cancer tissues and the adjacent non-neoplastic tissues. miR-133b mimics were overexpressed in GC cell lines, miR-133b inhibitors were also introduced in GES cells to investigate its role on regulating cell proliferation, cell migration and cell invasion. The target of miR-133b was identified by luciferase reporter assay and western blot. Fascin actin-bundling protein 1 (FSCN1) siRNA was used to achieve the knockdown of FSCN1 in GC cells and to investigate its role on modulating GC cell proliferation and invasion.

Results

miR-133b was significantly down-regulated in GC cell lines and in GC tissues compared with adjacent normal tissues. Moreover, lower-level of miR-133b was also associated with venous invasion and a more aggressive tumor phenotype. Re-introduction of miR-133b in GC cells can inhibit cell proliferation, cell migration and invasion. In contrary, knockdown of miR-133b in GES cells can promote cell proliferation and invasion. Further investigation indicated that miR-133b targeted FSCN1 in GC cells and knockdown of FSCN1 can also inhibit GC cell growth and invasion.

Conclusion

Our findings demonstrated that miR-133b was significantly down-regulated in GC tissues and exerted its tumor suppressor role in GC cells. The investigation of the detailed mechanism showed that miR-133b directly targeted FSCN1 which functioned as an oncogenic gene in GC cells. These results suggested that miR-133b can be developed as a new diagnostic marker or therapeutic target for GC.

13-acetoxysarcocrassolide induces apoptosis on human gastric carcinoma cells through mitochondria-related apoptotic pathways: p38/JNK activation and PI3K/AKT suppression

13-acetoxysarcocrassolide (13-AC), an active compound isolated from cultured Formosa soft coral Sarcophyton crassocaule, was found to possess anti-proliferative and apoptosis-inducing activities against AGS (human gastric adenocarcinoma cells) gastric carcinoma cells. The anti-tumor effects of 13-AC were determined by MTT assay, colony formation assessment, cell wound-healing assay, TUNEL/4,6-Diamidino-2-phenylindole (DAPI) staining, Annexin V-fluorescein isothiocyanate/propidium iodide (PI) staining and flow cytometry. 13-AC inhibited the growth and migration of gastric carcinoma cells in a dose-dependent manner and induced both early and late apoptosis as assessed by flow cytometer analysis. 13-AC-induced apoptosis was confirmed through observation of a change in ΔΨm, up-regulated expression levels of Bax and Bad proteins, down-regulated expression levels of Bcl-2, Bcl-xl and Mcl-1 proteins, and the activation of caspase-3, caspase-9, p38 and JNK. Furthermore, inhibition of p38 and JNK activity by pretreatment with SB03580 (a p38-specific inhibitor) and SP600125 (a JNK-specific inhibitor) led to rescue of the cell cytotoxicity of 13-AC-treated AGS cells, indicating that the p38 and the JNK pathways are also involved in the 13-AC-induced cell apoptosis. Together, these results suggest that 13-AC induces cell apoptosis against gastric cancer cells through triggering of the mitochondrial-dependent apoptotic pathway as well as activation of the p38 and JNK pathways.

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

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

Methylated CpG site count of dapper homolog 1 (DACT1) promoter prediction the poor survival of gastric cancer

OBJECTIVE

To elucidate the clinical significance of the methylated status of CpG sites of dapper homolog 1 (DACT1) promoter in the survival prediction in gastric cancer (GC).

METHODS

The large scale GC patients (n=459) were analyzed for the quantitatively methylated status of CpG sites of DACT1 DNA promoter with the bisulphite sequencing PCR (BSP). With gene sequencing analysis, the methylated statuses of 12 cytosine-phosphate-guanine (CpG) sites in DACT1 promoter were detected to supply detailed information for the precisely prognostic prediction. Associations between molecular, clinicopathologic, and survival data were analyzed.

RESULTS

With the MSP detection, different methylated levels of DACT1 promoter were identified in the 25 GC tissues, while none of 25 normal gastric mucosal tissues were found to be methylated. DACT1 promoter methylation was found in 28.32% in 459 patients. GC patients with 4 or more methylated CpG sites of DACT1 promoter was significantly associated with the poorer survival (P=0.19). The methylated statuses of CpG -515, CpG -435, and CpG -430 sites were also identified to provide the elaborate survival discrimination for 459 GC patients, respectively (P=0.049, =0.006, and =0.037). In addition, we demonstrated that the methylated CpG site count had smallest AIC and BIC values than other three methylated status of CpG sites for prediction the survival of 459 GC patients.

CONCLUSIONS

The methylated CpG site count of DACT1 promoter had the significant applicability for clinical evaluation the prognosis of GC.

Increased expression of phospho-acetyl-CoA carboxylase protein is an independent prognostic factor for human gastric cancer without lymph node metastasis

Upregulation of acetyl-CoA carboxylase (ACC), as a rate-limiting enzyme of fatty acid synthesis,has been recognized in multiple human cancers, implicating a critical role in cancer development and progression; yet, its role in gastric cancer still remains unclear. In the present study, we detected ACC and phosphorylated form of ACC (pACC) expression in gastric cancers and explored its clinical significance. Tissue microarray blocks containing primary gastric cancer and adjacent normal mucosa specimens obtained from 1,072 Chinese patients were used for the detection of ACC and pACC expression by immunohistochemistry. Gastric cancer cell lines were treated by metformin, and pACC was measured by Western blotting. ACC overexpression was observed in all the tumor specimens. High expression of pACC was found in 630 (58.8 %) of the 1,072 primary tumors and in 237 (66.6 %) of the 356 primary tumors without lymph node metastasis. Absent/low expression of pACC significantly correlated with advanced T stage (P < 0.001), tumor size (P = 0.010), lymph node metastasis (P < 0.001), advanced disease stage (P < 0.001), and poor histological differentiation (P = 0.014) in 1,072 primary tumors, and with advanced T stage (P = 0.015), tumor size (P = 0.017), and poor histological differentiation (P = 0.001) in 356 tumors without lymph node metastasis. Kaplan-Meier analysis showed that high expression of pACC is strongly related to better survival rates in all gastric cancer patients (P = 0.006). Cox regression analysis revealed that pACC is an independent prognostic factor only in patients without lymph node metastasis (P = 0.016). Metformin treatment leaded to increased expression of pACC, which, in turn, resulted in the reduction of cell proliferation and colony formation of gastric cancer cells (P < 0.05). Increased activation of ACC is frequent in human gastric cancer, and downregulation of pACC is an important prognostic factor, suggesting that ACC/pACC might be a potential target for cancer intervention.

Prognostic role of lemur tyrosine kinase 3 in postoperative gastric cancer

The treatment of gastric cancer has been unsatisfactory thus far; therefore, novel targets and treatment strategies are urgently required. Lemur tyrosine kinase (LMTK)3 is an estrogen receptor-α (ERα) modulator with a central role in endocrine resistance in breast cancer. Moreover, the expression and polymorphisms of LMTK3 are correlated with the prognosis of breast cancer patients. Since estrogen receptor (ER) is also expressed and plays a role in gastric cancer, we herein investigated the expression of the LMTK3 protein in 83 gastric cancer patients by tissue microarray and analyzed the correlation between LMTK3 expression and the prognosis of gastric cancer. Our results demonstrated that LMTK3 was more frequently expressed in gastric cancer tissues compared to non-cancerous mucosa (79.5 vs. 45.8%, respectively; P=0.000). The LMTK3 expression was significantly correlated with the depth of invasion (P=0.002) and disease stage (P=0.035). The Kaplan-Meier analysis revealed that the postoperative survival of the LMTK3-negative group was superior to that of the LMTK3-positive group (P=0.043). Moreover, the multivariate analysis identified LMTK3 expression as an independent prognostic factor for patients with gastric cancer (P=0.019). These findings suggested that the expression of LMTK3 may be a negative prognostic factor in patients with gastric cancer. Moreover, targeting LMTK3 is a potential strategy for the treatment of gastric cancer, although the biological functions of LMTK3 in gastric cancer require further investigation.

Efficacy of SOX regimen versus XELOX regimen in concurrent chemoradiotherapy for postoperative recurrent gastric carcinoma

AIM: To evaluate the efficacy and safety of SOX regimen (S-1 + L-OHP) versus XELOX regimen (capecitabine + L-OHP) in concurrent chemoradiotherapy for postoperative recurrent gastric carcinoma.

METHODS: Sixty-six elderly patients with postoperative recurrent gastric cancer were randomly divided into two groups: an SOX group (n = 34) and a XELOX group (n = 32). The SOX group received oral S-1 (< 1.25 m², 40 mg; 1.25-1.5 m2, 50 mg; > 1.5 m², 60 mg), twice daily, d1-14; L-OHP (85 mg/m², d1); and three-dimensional conformal radiation (1.8 Gy/d, 5 d/wk and the total dose was 45 Gy). The XELOX group was treated with capecitabine (2000 mg/m², separated to twice, d1-14), plus the same regimen of radiation and L-OHP as those in the SOX group. Each cycle lasted three weeks. The efficacy and toxicity were evaluated after two cycles of treatment.

RESULTS: The efficacy and toxicity could be evaluated in 66 cases. There were no significant differences in the overall response rate (55.9% vs 46.9%), median time to progression (TTP) (6.3 mo vs 5.8 mo) or median overall survival (OS) (12.8 mo vs 12.2 mo) (P > 0.05) between the two groups. The most common toxicities in the two groups were neutropenia, thrombopenia, nausea, vomiting and diarrhea, all of which could be tolerated. However, the incidence of hand-foot syndrome was significantly higher in the SOX group than in the XELOX group (P < 0.05).

CONCLUSION: The efficacy of chemoradiotherapy based on the SOX regimen for postoperative recurrent gastric carcinoma is better than that of concurrent chemoradiotherapy based on the XELOX regimen in terms of well-tolerated toxicity.

Cortactin expression confers a more malignant phenotype to gastric cancer SGC-7901 cells

AIM: To study the effects of cortactin on the tumor biology of SGC-7901 cells and identify the mechanism involved in the process.

METHODS: Cell lines in which cortactin was stably overexpressed or knocked down as well as the respective control cell lines were established by standard molecular methods. The effects of cortactin on the proliferation, migration and invasion capacity of SGC-7901 cells were assessed by the MTT assay, colony formation, flow cytometry, transwell migration and matrigel invasion. Nude mouse models were also used to assess the role of cortactin in the growth and metastasis of SGC-7901 cells in vivo. Western blotting analysis was performed to detect the expression of epidermal growth factor receptor (EGFR) and downstream molecules.

RESULTS: Cell lines in which cortactin was stably overexpressed or knocked down as well as control cell lines were successfully established and designated as LV5-cortactin-SGC, LV5-SGC, LV3-shRNA-SGC and LV3-SGC. Cortactin overexpression promoted SGC-7901 cell migration (340.7 ±12.6 vs 229.1 ± 23.2, P < 0.01) and invasion (71.6 ± 5.2 vs 48.4 ± 3.6, P < 0.01). Cortactin downregulation impaired SGC-7901 cell migration (136.2 ± 19.8 vs 225 ± 17) and invasion (29.2 ± 5.2 vs 49.6 ± 3.8, P < 0.01). The results from the MTT and colony formation assays results indicated increased LV5-cortactin-SGC cell proliferation and decreased LV3-shRNA-SGC cell proliferation compared to the control cells. Flow cytometry analysis demonstrated that cortactin overexpression promoted the proliferation index of SGC-7901 cells, and the results were reversed when cortactin was downregulated. Mouse tumor models confirmed that cortactin expression increased SGC-7901 cell proliferation and metastasis in vivo. Western blotting analysis revealed that cortactin elevated EGFR expression and activated the downstream molecules.

CONCLUSION: Cortactin expression promoted the migration, invasion and proliferation of SGC-7901 cells both in vivo and in vitro. The EGFR signaling pathway is mechanistically involved.

Biomarkers of epithelial-mesenchymal transition in gastric cancer

In gastric cancer, metastases are the major cause of death. Understanding the mechanism by which tumor cells invade and metastasize is essential to develop novel treatments for gastric cancer (GC). Epithelial-mesenchymal transition (EMT) is a multistage process in which epithelial cells develop into mesenchymal-like cells with a large number of distinct genetic and epigenetic alterations. EMT also occurs in cancer, which endows invasive and metastatic properties upon cancer cells that favor successful colonization of distal target organs. Here, we summarize studies of known EMT biomarkers in the context of GC progression. The biomarkers discussed include cell-surface proteins (E-cadherin and N-cadherin), cytoskeletal proteins (β-catenin and Vimentin), and transcription factors (Snail, Twist, ZEB1 and ZEB2).

Tetrandrine induces mitochondria-mediated apoptosis in human gastric cancer BGC-823 cells

Tetrandrine, a bis-benzylisoquinoline alkaloid isolated from the dried root of Hang-Fang-Chi (Stephaniatetrandra S. Moore), has been reported to possess anti-cancer effects on many tumors. In this study, we investigated tetrandrine-induced apoptosis on human gastric cancer BGC-823 cells in vitro and in vivo. The results showed that tetrandrine significantly inhibited cell viability in a dose- and time-dependent manner and induced apoptosis. It increased the apoptosis; upregulation of Bax, Bak, and Bad; and downregulation of Bcl-2 and Bcl-xl in BGC-823 cells. Moreover, tetrandrine increased the activation of caspase-3 and -9, release of cytochrome c, and upregulation of apaf-1, suggesting that tetrandrine-induced apoptosis was related to the mitochondrial pathway. Meanwhile, pretreatment with the pan-caspase inhibitor z-VAD-fmk in BGC-823 cells reduced tetrandrine-induced apoptosis by blocking activation of caspases. Furthermore, tetrandrine effectively inhibited tumor growth via apoptosis induction, which was verified by immunohistochemical analysis in a nude mouse xenograft model. Taken together, we concluded that tetrandrine significantly inhibited the proliferation of gastric cancer BGC-823 cells through mitochondria-dependent apoptosis, which may play a promising role in gastric cancer therapy.

Sinomenine sensitizes gastric cancer cells to 5-fluorouracil in vitro and in vivo

Sinomenine (SIN) has been reported to exert antitumor effects in various types of human cancer. The present study aimed to investigate the effects of SIN on gastric cancer and to briefly address its mechanism of action. In this study, the single and combined effects of SIN with 5-fluorouracil (5-FU) on human gastric cancer cells were assessed using an MTT assay, a combination index method and an MKN-28 xenograft mice model. Levels of apoptosis were determined using Hoechst 33258 staining and flow cytometry. Expression levels of certain apoptosis-related proteins were examined by western blotting. mRNA levels of the 5-FU-associated gene, thymidylate synthase (TS), were measured by RT-PCR. The results showed that SIN enhances 5-FU-mediated cellular growth inhibition and apoptosis in gastric cancer cells, reduces TS mRNA accumulation and activates the mitochondrial apoptotic pathway. The same chemotherapy sensitizer effect of SIN was confirmed in vivo. SIN is a promising chemotherapy sensitizer for 5-FU. Our results indicate that this may be a potential combination chemotherapeutic strategy for gastric cancer.

A genetic polymorphism in TOX3 is associated with survival of gastric cancer in a Chinese population

Purpose

Recently, genetic polymorphism (rs3803662C>T) in TOX3 was reported to induce the risk of breast cancer. In this study, we hypothesized that rs3803662 could influence gastric cancer survival outcomes.

Methods

With multiplex SNaPshot method, we genotyped TOX3 rs3803662 in 880 gastric patients with surgical resection. The association between genotype and survival outcomes was performed by the Kaplan-Meier method, Cox regression analysis models and the log-rank test.

Results

There was no association in the analyses of rs3803662 and survival of gastric cancer. However, the stratified analysis by histology showed that rs3803662 CT/TT genotype was associated with a significantly better survival for diffuse-type gastric cancer (log-rank p = 0.030, hazard ratio [HR]  = 0.67, 95% confidence interval [CI]  = 0.46–0.96), than the CC genotype. In addition, this favorable effect was especially obvious among gastric cancer patients with tumor size >5 cm, T3 and T4 depth of invasion, lymph node metastasis, no drinking, no distant metastasis, no chemotherapy and gastric cardia cancer.

Conclusions

TOX3 rs3803662 might play an important role in the prognostic outcome and treatment of gastric cancer, especially perhaps further help in explaining the reduced risk of death associated with diffuse-type gastric cancer.

Intracellular poly(I:C) initiated gastric adenocarcinoma cell apoptosis and subsequently ameliorated NK cell functions

Natural killer (NK) cells are granular lymphocytic cells that exert essential functions in viral infection defense and tumor immune surveillance. However, the functions of NK cells were impaired in cancer patients. Polycytidylic acid [poly(I:C)] has been used as an immune adjuvant to improve innate and adaptive immune responses. In this study, intracellular poly(I:C) could trigger gastric adenocarcinoma cells apoptosis quickly. Meanwhile, the sensitivity of poly(I:C)-treated gastric adenocarcinoma cells to NK cell cytolysis was increased, concomitant with the elevated expression of MICA/B and Fas. Furthermore, the cytolytic activity of NK cells against tumor cells was augmented significantly by the supernatant from poly(I:C)-transfected tumor cells compared with NK cells treated by the supernatant from untreated tumor cells, as well as the proliferation and migration abilities of NK cells. In this process, the activating receptors and cytolysis-associated molecules of NK cells were up-regulated. Further investigation showed that type I interferon (IFN) produced by poly(I:C)-transfected gastric adenocarcinoma cells played an important role in this process. Our findings demonstrated that intracellular poly(I:C) not only triggered gastric adenocarcinoma cell apoptosis, but also enhanced NK responses via inducing type I IFN production by gastric adenocarcinoma cells. These functions make poly(I:C) a promising therapeutic medicine for gastric adenocarcinoma.

(Neo)-adjuvant chemo(-radio) therapy for adenocarcinomas of the gastroesophageal junction and the stomach in the West

Worldwide, the treatment of adenocarcinomas of the gastroesophageal junction and stomach has changed over the past decades. It is no longer surgery alone. Nowadays, most patients undergo surgery plus pre- and/or postoperative therapies. However, there are still marked differences in surgical procedures between the East and the West which might influence the surgical prognosis and thereby also the choice of perioperative treatment strategies. In the East, with its more extended surgical procedures, including standard D2 dissections, the current treatment philosophy is primary surgery followed by adjuvant chemotherapy. Neoadjuvant approaches are restricted to really advanced tumors, and perioperative chemoradiation is not routinely used (at least to date). This clearly differs from treatment strategies currently recommended in Western countries. In Europe and North America, pre- plus postoperative chemotherapy has become the recommended treatment for locally more advanced tumors, and preoperative chemoradiation is increasingly administered to patients with adenocarcinomas of the gastroesophageal junction (Siewert type I/II). However, the role of postoperative chemotherapy (despite its increasing use) is still under discussion in the West (especially Europe) and not generally recommended/accepted as a standard treatment. Postoperative chemoradiation, which is one standard treatment in North America, is only regarded as a treatment option for patients after 'inadequate surgery' (i.e. <D2 dissection) in many European countries.

Tying the knot between cytokine and toll-like receptor signaling in gastrointestinal tract cancers

Inflammation-associated malignancies of the gastrointestinal tract (GI), including those of the stomach and colon, collectively rank as the highest cause of cancer-related deaths worldwide. It has been well documented that the deregulated activation of the archetypal pro-inflammatory and oncogenic transcription factors nuclear factor-kappa B (NF-κB) and signal transducer and activator of transcription (STAT)3 is a common feature of GI cancers that invariably correlates with poor prognosis. Signal transducer and activator of transcription 3 and NF-κB are key downstream signal transducers of the interleukin (IL)-6 cytokine and toll-like receptor (TLR) families, respectively, and until recently, the potential involvement of these two families in the pathogenesis of cancer has been investigated in isolation. However, there is now emerging evidence of the complex interplay between the IL-6 cytokine and TLR families in GI tract cancers, with a surprising twist in the identification of a non-immune role for specific TLR family members. In this review, we discuss the molecular mechanisms associated with cross-talk between the IL-6 cytokine family/STAT3 signaling network and the TLR family/NF-κB signaling network, and we address the potential benefit of their therapeutic targeting in gastric and colorectal cancers.

Protective role of Helicobacter pylori infection in prognosis of gastric cancer: evidence from 2,454 patients with gastric cancer

BACKGROUND

A number of studies have investigated the association between Helicobacter pylori (H. pylori) infection and the prognosis of gastric cancer (GC), with inconsistent and inconclusive results. We performed a meta-analysis to derive a more precise estimation of the association.

METHODOLOGY/PRINCIPAL FINDINGS

A systematic search of PubMed, EMBASE, Cochrane and Chinese wanfang databases was performed with the last search updated on February 19, 2013. The hazard ratio (HR) and its 95% confidence interval (95%CI) were used to assess the strength of association. A total of 12 studies including 2454 patients with GC were involved in this meta-analysis. The pooled HR was 0.71 (95%CI: 0.57-0.87; P = 0.001) for OS and 0.60 (95%CI: 0.30-1.18; P = 0.139) for DFS in GC patients, respectively. The protective role of H. pylori infection in the prognosis of GC was also observed among different subgroups stratified by ethnicity, statistical methodology, H. pylori evaluation method and quality assessment. There was no evidence of publication bias.

CONCLUSIONS/SIGNIFICANCE

This meta-analysis suggests a protective role for H. pylori infection in the prognosis of GC. The underlying mechanisms need to be further elucidated, which could provide new therapeutic approaches for GC.

Enhanced RegIV expression predicts the intrinsic 5-fluorouracil (5-FU) resistance in advanced gastric cancer

AIM

RegIV, a member of the Regenerating (REG) gene family, may be a marker for the prediction of resistance to 5-fluorouracil (5-FU)-based chemotherapy. However, the relationship between the intrinsic drug resistance of gastric cancer (GC) cells to 5-FU used alone (single FU) or in multidrug therapeutic regimens (5-FU combinations) and RegIV expression has not been investigated.

METHODS

The patient cohort comprised 45 patients with primary GC. The chemoresistance of GC cells to therapeutic regimens consisting of single 5-FU or FU combinations was investigated using the ATP-tumor chemosensitivity assay. The level of RegIV mRNA transcripts was determined by real-time reverse transcriptase-PCR. RegIV expression was evaluated as a novel predictive biomarker for the intrinsic drug resistance of primary GC cells to single 5-FU or 5-FU combinations.

RESULTS

Upregulation of RegIV mRNA transcripts was observed in 36 of the 45 tumor specimens and was positively correlated with the invasive depth of the tumor cells (p = 0.000), the clinical stages (p = 0.000) and the in vitro intrinsic drug resistance of primary GC cells to 5-FU (p = 0.000) or 5-FU combinations.

CONCLUSION

RegIV mRNA transcript level was strongly associated with the intrinsic resistance of GC cells to single 5-FU or 5-FU combinations, suggesting that RegIV may play an important role in the intrinsic resistance of GC cells to 5-FU and that targeted therapy against the RegIV gene could be applied to overcome 5-FU resistance in the treatment of GC.

[Surgery of gastric cancer in a medium volume center]

BACKGROUND

The aim of the study was to evaluate prognostic factors for the surgical treatment of gastric cancer in a medium volume center. The investigation focused in particular on morbidity and mortality.

PATIENTS AND METHODS

From January 2005 to August 2011 a total of 74 patients with gastric cancer were surgically treated in our medium volume center. The study of these patients included morbidity, mortality, UICC (International Union Against Cancer) stage, Laurén classification, surgical therapy procedure, American Society of Anesthesiologists (ASA) classification and duration of surgery.

RESULTS

After surgery 11 patients suffered from complications with a morbidity of 14.9% and a mortality of 1.4% (n=1). No significant differences could be detected during the study period.

CONCLUSION

In comparison to other studies the morbidity and mortality rates signify similar to better data than complications of high volume centers which might be due to the small group of surgeons who are specialized in gastric surgery.