Current management of gastric cancer

Circ_PABPC1 promotes the malignancy of gastric cancer through interacting with ILK to activate NF-κB pathway

BACKGROUND

Gastric cancer (GC) is a common cancer type with both high incidence and mortality. Recent studies have revealed an important role of circRNA in the development of GC. However, more experiments are needed to reveal the precise molecular mechanisms of circRNA in GC development.

METHODS

Bioinformatics analysis was conducted to predict the potential role of circ_PABPC1 in GC and the target proteins of circ_PABPC1. Quantitative RT-PCR, Western blot and immunohistochemistry assays were conducted to detect the levels of circ_PABPC1, NF-κB p65, NF-κB p65 (Ser536) and ILK. MTT, Edu staining, cell scratch-wound and trans-well assays were carried out to detect cell proliferation, migration and invasion. The interaction between ILK and circ_PABPC1 was confirmed by RNA immunoprecipitation (RIP), RNA pull-down and fluorescence in situ hybridization assays. Genetically modified GC cells were injected into mice to evaluate the tumor growth performance.

RESULTS

This study found that the high expression of circ_PABPC1 was associated with a poor prognosis of GC. The up-regulation of circ_PABPC1 promoted the proliferation, migration and invasion of GC cells. Circ_PABPC1 bound to ILK protein, thereby preventing the degradation of ILK. ILK mediated the effect of circ_PABPC1 on GC cells through activating NF-κB.

CONCLUSION

circ_PABPC1 promotes the malignancy of GC cells through binding to ILK to activate NF-κB signaling pathway.

Relación del índice nutricional pronóstico con complicaciones y mortalidad en los pacientes con cáncer gástrico sometidos a gastrectomía en un hospital de tercer nivel de Bogotá, Colombia

Introducción. El cáncer gástrico es el quinto cáncer diagnosticado con mayor frecuencia y la tercera causa de muerte por cáncer en el mundo. En el tratamiento quirúrgico, la evidencia actual apoya las medidas preoperatorias e índices pronósticos para mejorar la supervivencia. El índice nutricional pronóstico, que une los valores de los linfocitos circulantes en sangre periférica con los de la albúmina sérica, ha presentado características de ser un marcador nutricional e inmunológico con valor predictivo sobre complicaciones y mortalidad. El objetivo de este estudio fue determinar la relación entre el índice nutricional pronóstico con las complicaciones y mortalidad en pacientes con cáncer gástrico sometidos a gastrectomía. Métodos. Se llevó a cabo un estudio observacional descriptivo, de corte transversal, con componente analítico, mediante la revisión retrospectiva de las historias clínicas. Resultados. Se analizaron 113 pacientes sometidos a gastrectomía total o subtotal. Se encontró asociación entre el índice nutricional pronóstico y la mortalidad; todos los pacientes que murieron tenían un índice menor o igual a 46. También se encontró asociación inversa entre el valor del índice y la presentación de complicaciones posoperatorias, como sepsis, peritonitis, fuga de la anastomosis y sangrado. Discusión. Similar a nuestro análisis, varios estudios plantean que un índice nutricional pronóstico bajo podría tener un valor predictivo sobre la frecuencia de complicaciones y supervivencia global en pacientes con cáncer gástrico llevados a cirugía. Conclusión. El índice nutricional pronóstico se asocia con la mortalidad y complicaciones posoperatorias en pacientes sometidos a gastrectomía por cáncer gástrico.

Ribosomal DNA copy number is associated with P53 status and levels of heavy metals in gastrectomy specimens from gastric cancer patients

The ribosomal DNA (rDNA) can act as a sensor and responder of cancer-associated stress. Here we investigated rDNA copy number in gastric cancers and its association with existing biomarkers and metals exposure. This study was performed on paired tumor and adjacent normal tissues obtained from 65 gastric cancer patients who underwent gastrectomy. Immunohistochemistry was used to assess HER-2, E-cadherin, EGFR, CK (pan), CK20, CK7, TopoⅡ, CAM5.2, P53, and Ki-67 expression. Inductively coupled plasma mass spectrometry (ICP-MS) was used to detect the concentrations of 17 metals in gastric tissues. rDNA copy number was detected by qPCR in genomic DNA isolated from tissue samples. Associations between the expression of existing markers, metal concentrations, and rDNA copy number were evaluated. Within patients with gastric cancer, the copy number of the 45S rDNA components (18S, 5.8S, 28S) and the 5S rDNA in tumor tissues were significantly higher than those in adjacent normal tissues, whereas mitochondrial DNA (mtDNA) copy number was significantly lower in tumor tissues than that in adjacent normal tissues. Further analysis revealed that the increase in 18S, 5.8S, and 28S rDNA copy number in tumor tissues was diminished in the context of EGFR and P53 loss. Moreover, analysis of metals revealed particularly high concentrations of As, Cd, Cr, Cu and Fe in the gastric tissues of these patients. Intriguingly, rDNA copy number variation across individuals was correlated with the concentrations of some metals. The rDNA was amplified in tumor tissues of gastric cancer patients, and its amplification may be associated with metals exposure. The expression of EGFR and P53 may influence rDNA copy number, with diminished amplification of the rDNA in cancers that were negative for these biomarkers. Our observation further our understanding of rDNA copy number in gastric cancer and its potential as a simple and useful marker in gastric cancer monitoring.

Time to local recurrence as a predictor of survival in unrecetable gastric cancer patients after radical gastrectomy

Local recurrence is common after radical surgery. However, the factors that contribute to survival after local recurrence remain unclear. In this retrospective study we analyzed the relationship between time to recurrence and survival after recurrence in 74 patients with locally recurrent gastric cancer. All patients received palliative radiotherapy with or without chemotherapy. The patients were divided into two groups according to the time between gastrectomy and local recurrence: early local recurrence (ELR, < 12 months after primary surgery), and late local recurrence (LLR, ≥12 months after primary surgery). The median overall survival (OS) time was 15 months for patients with ELR and 25 months for LLR patients. Univariate and multivariate analysis revealed that time to local recurrence was significantly associated with OS after local recurrence (P = 0.001). The hazard ratio of ELR compared with LLR patients was 0.442 (95% confidence interval: 0.264-0.741). These results indicate that early local recurrence predicted poor prognosis in gastric cancer patients with unresectable local recurrence.

Role of Hydro-Dissection Facilitated Monopolar Cauterization Dissection Technique on Separation of the Greater Omentum From the Superior Layer of the Transverse Mesocolon During D2 Radical Gastrectomy

Adequate separation of the omentum from the transverse colon mesentery, during D2 radical gastrectomy, is usually difficult and often time-consuming due to anatomic variations. The aim of this prospective study was to compare the electrocautery dissection technique with hydrodissection-facilitated electrocauterization for the separation of the greater omentum from the superior layer of the transverse mesocolon in gastric cancer patients undergoing D2 radical gastrectomy. The time taken to separate the greater omentum from the superior layer of the transverse mesocolon, and the number and extension of iatrogenically-created mesocolonic defects were assessed. Forty patients were prospectively randomized into 2 groups. Separation of the greater omentum from the superior layer of the transverse mesocolon was achieved in Group I (n = 20) patients by the monopolar cauterization dissection technique whereas in Group II (n = 20) patients by the hydrodissection-facilitated monopolar cauterization. No significant difference was found between the 2 groups in terms of age, gender, body mass index (BMI), type of surgical technique, or the number of resected lymph nodes (P &gt; 0.05). The difference between the 2 dissection techniques was not statistically significant when compared according to the number of iatrogenic mesocolonic defects, extension of the defects, or the time period required for the separation of greater omentum from the superior layer of the transverse mesocolon (P &gt; 0.05). The overall survival was not significantly different between the 2 dissection techniques (P &gt; 0.05). Hydrodissection is a safe technique that can be applied as an adjunct to electrocauterization to facilitate the dissection in the correct plane during resection of the mesogastrium.

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.

CHK1 expression in Gastric Cancer is modulated by p53 and RB1/E2F1: implications in chemo/radiotherapy response

Radiation has a limited but relevant role in the adjuvant therapy of gastric cancer (GC) patients. Since Chk1 plays a critical function in cellular response to genotoxic agents, we aimed to analyze the role of Chk1 in GC as a biomarker for radiotherapy resistance. We analyzed Chk1 expression in AGS and MKN45 human GC cell lines by RT-QPCR and WB and in a small cohort of human patient’s samples. We demonstrated that Chk1 overexpression specifically increases resistance to radiation in GC cells. Accordingly, abrogation of Chk1 activity with UCN-01 and its expression with shChk1 increased sensitivity to bleomycin and radiation. Furthermore, when we assessed Chk1 expression in human samples, we found a correlation between nuclear Chk1 accumulation and a decrease in progression free survival. Moreover, using a luciferase assay we found that Chk1’s expression is controlled by p53 and RB/E2F1 at the transcriptional level. Additionally, we present preliminary data suggesting a posttranscriptional regulation mechanism, involving miR-195 and miR-503, which are inversely correlated with expression of Chk1 in radioresistant cells. In conclusion, Chk1/microRNA axis is involved in resistance to radiation in GC, and suggests Chk1 as a potential tool for optimal stratification of patients susceptible to receive adjuvant radiotherapy after surgery.

Systematic review on quality of life outcomes after gastrectomy for gastric carcinoma

BACKGROUND

Despite advances in chemotherapy and radiotherapy, gastrectomy is the only curative intervention for gastric carcinoma. This study reviews post-operative health-related quality of life (HRQOL) after gastrectomy.

METHODS

A literature search was conducted on PubMed for all studies published after January 2000 matching strict eligibility criteria. Bibliographies of included studies were also reviewed. Quality appraisal and data tabulation were performed using pre-determined forms. Results were synthesised by narrative review according to PRISMA guidelines with full tabulation of results of all included studies.

RESULTS

A total of 21 studies (3,575 patients) were included. Post-operative HRQOL improvements were demonstrated across most or all domains in different HRQOL instruments. Patients experienced declines in HRQOL 1 month after surgery, but reached at least pre-operative levels with recovery by 1 year. The greatest improvements were demonstrated in the emotional health domain with favourable functional benefits. Partial gastrectomy appears to be superior to total gastrectomy in physical, emotional and functional health domains. However, patients remain susceptible to gastrointestinal symptoms following surgery, which negatively impact upon HRQOL. Post-operative complications did not appear to affect HRQOL. Most studies were prospective, but data is heterogeneous.

CONCLUSIONS

Gastrectomy results in significant HRQOL benefits across a broad range of health domains. This is critical outcome of surgery and an important consideration in pre-operative decision making.

Concurrent involved-field radiotherapy and XELOX versus XELOX chemotherapy alone in gastric cancer patients with postoperative locoregional recurrence

PURPOSE

To compare the treatment outcomes of concurrent involved-field radiotherapy and XELOX (oxaliplatin and capecitabine) versus XELOX chemotherapy alone in gastric adenocarcinoma patients with locoregional recurrence.

MATERIALS AND METHODS

From 2004 to 2008, 79 patients with recurrent locoregional gastric cancer after curative resection of gastric tumor were enrolled. Among them, 41 patients received involved-field radiotherapy (median dose 50 Gy) by a 3-dimensional conformal radiotherapy technique and concurrent XELOX chemotherapy, and 38 patients were treated with XELOX chemotherapy alone (oxaliplatin 130 mg/m, capecitabine 1000 mg/m, twice daily, 3 wk each cycle).

RESULTS

The concurrent radiochemotherapy group showed better overall response (including complete response and partial response) when compared with the chemotherapy group (87.8% vs. 63.0%, P=0.01). The control rates for pain, bleeding, and dysphagia/obstruction were 89.5% (17/19), 81.8% (9/11), and 80% (8/10), respectively, in the radiochemotherapy group and 58.8% (10/17), 50% (5/10), and 57.1% (4/7), respectively, in the chemotherapy group. The concurrent radiochemotherapy group showed better overall symptom-control rate when compared with the chemotherapy group (55.9% vs. 85%, P=0.006). Patients receiving concurrent radiochemotherapy trended toward a better median overall survival when compared with those receiving chemotherapy alone (13.4 vs. 5.4 mo, P=0.06). In addition, there were no significant differences in the rates of toxicity or adverse reactions between the 2 groups.

CONCLUSIONS

Concurrent involved-field radiotherapy and XELOX showed better responses and overall symptom-control rates compared with XELOX chemotherapy alone in gastric cancer patients with postoperative locoregional recurrence. A trend of survival benefit from radiochemotherapy was also observed but needs to be further explored.

IL-33 Promotes Gastric Cancer Cell Invasion and Migration Via ST2-ERK1/2 Pathway

BACKGROUND

As a pro-inflammatory cytokine, IL-33 has been demonstrated to play an important role in tumor progression. It is reported that IL-33 is highly expressed in the serum and tumor tissues of patients with gastric cancer. However, the function of IL-33 in gastric cancer remains elusive. We here tried to elucidate the effects of IL-33 on gastric cancer cell invasion and migration.

METHODS

Invasion assay and migration assay were performed to assess the effects of IL-33 on gastric cancer cell invasion and migration. ST2 receptor was silenced by siRNA, and ERK1/2 pathway was inhibited by U0126. Protein levels of MMP-3 and IL-6 in cell supernatant were measured by ELISA.

RESULTS

IL-33 promoted the invasion and migration of gastric cancer cells, in a dose-dependent manner. Knockdown of the IL-33 receptor ST2 attenuated the IL-33-mediated invasion and migration. Furthermore, via ST2 receptor, IL-33 induced the activation of ERK1/2 and increased the secretion of MMP-3 and IL-6. In addition, blockage of ERK1/2 pathway resulted in inhibition of invasion and migration induced by IL-33, and downregulation of MMP-3 and IL-6 production.

CONCLUSIONS

IL-33 promotes gastric cancer cell invasion and migration by stimulating the secretion of MMP-3 and IL-6 via ST2-ERK1/2 pathway. Thus, IL-33 may be a useful marker for the diagnosis and treatment of gastric cancer.

Nucleotide excision repair related gene polymorphisms and genetic susceptibility, chemotherapeutic sensitivity and prognosis of gastric cancer

Human genomic DNA is in a dynamic balance of damage and repair. Cells employ multiple and specific repair pathways, such as nucleotide excision repair (NER), as unrepaired DNA damage has deleterious consequences and could give rise to carcinogenesis. Gene polymorphisms play a crucial role in predicting the risk and prognosis of cancer. Polymorphisms of NER-related genes could alter the ability of NER to effectively monitor and repair DNA damage, and thus may be associated with genetic susceptibility, chemotherapeutic sensitivity and prognosis of cancer. In recent years, increasing studies have focused on the association between polymorphisms of NER genes and gastric cancer, the world's fourth most common cancer and the second most common cause for cancer-related death. Here we reviewed the recent studies on the associations between polymorphisms of NER genes and gastric cancer from perspectives of genetic susceptibility, chemotherapeutic sensitivity and prognosis.

Systematic review and meta-analysis of the effectiveness and safety of extended lymphadenectomy in patients with resectable gastric cancer

Background

The extent of lymphadenectomy in the treatment of gastric cancer has been debated for more than two decades. This meta-analysis sought to evaluate the effectiveness and safety of extended lymphadenectomy in patients with gastric cancer.

Methods

A comprehensive search was performed to identify randomized clinical trials (RCTs) comparing the outcomes of D1 and D2 dissection for gastric cancer in PubMed, EMBASE, the Cochrane Library, Science Citation Index, Web of Science and the Chinese Biomedical Literature Database in any language from inception of the database to March 2012. Meta-analyses were performed using Review Manager software.

Results

Eight RCTs including a total of 2044 patients (D1, 1042; D2, 1002) were eligible for meta-analysis. Five-year survival and haemorrhage rates were similar in the two groups. There were significant differences in morbidity, anastomotic leakage, pancreatic leakage, reoperation rates, wound infection, pulmonary complications and postoperative mortality, all of which favoured D1 dissection. Subgroup analysis indicated a trend towards lower gastric cancer-related mortality in patients undergoing D2 dissection who did not also have resection of the spleen or pancreas.

Conclusion

D2 dissection was associated with a significantly higher postoperative risk. A trend towards lower gastric cancer-related mortality was found following D2 dissection that did not include resection of the spleen or pancreas, but further long-term survival data are needed to determine whether there is a specific survival benefit after D2 dissection.

Lymph node ratio is a better prognosticator than lymph node status for gastric cancer: A retrospective study of 138 cases

To study the clinical significance of lymph node ratio (LNR) in gastric cancer (GC), this study analyzed 613 patients with GC who underwent surgical resection. Of 613 patients with GC, 138 patients who had >15 lymph nodes (LNs) resected and radical resection were enrolled into the final study. All major clinicopathological data were entered into a central database. LNR was defined as the ratio of the number of metastatic LNs to the number of removed LNs. In order to determine the best cut-off points for LNR, the log-rank test and X-tile were used. LNR was then substituted for lymph node status (pN) in the 7th American Joint Committee on Cancer tumor-node-metastases (TNM) staging system and this was defined as the tumor-node ratio-metastases (TRM) staging system. Pearson's correlation coefficient (r) was used to study the correlations among the number of removed LNs, pN and LNR. The Kaplan-Meier survival curve was used to study the survival status, and the log-rank test and Cox proportional hazards model were used to identify the independent factors for survival. Receiver operating characteristic curve analysis was used to determine the predictive value of the parameters. By the time of last follow-up (median follow-up period, 38.3 months; range, 9.9-97.7 months), the median overall survival (OS) was 23.9 months [95% confidence interval (CI), 18.8-29.0 months]. The 1-, 2-, 3- and 5-year survival rates were 76.8, 57.2, 50.0 and 46.4%, respectively. The cut-off points were 0, 0.5 and 0.8 (R0, LNR=0; R1, LNR ≤0.5; R2, 0.5> LNR ≤0.8; and R3, LNR >0.8). Univariate and multivariate analyses revealed that both LNR and pN were independent prognostic factors for GC. LNR could better differentiate OS in patients than LN. In addition, the TRM staging system was better at predicting the clinical outcomes than the TNM staging system, and LNR was better than pN. In conclusion, LNR was a better prognosticator than pN for GC.

Tetraspanin CD151 expression associated with prognosis for patients with advanced gastric cancer

PURPOSE

Tetraspanin CD151 is known to be involved in cancer invasion and metastasis, and its overexpression appears to be associated with a poor prognosis for various types of cancer. However, the expression status of CD151 and its prognostic impact in advanced gastric cancer (AGC) has not yet been clarified.

METHODS

Immunohistochemistry was used to investigate the expression of CD151, c-erbB2, and c-Met in 159 cases of AGC. The clinicopathological and prognostic significance of these biomarkers were then evaluated.

RESULTS

The overexpression of CD151 was observed in a subset of advanced gastric adenocarcinomas (25.8 %), and c-erbB2 and c-Met were overexpressed in 15.1 and 35.2 % of the cohort, respectively. CD151 overexpression was more frequently observed in tumors from younger patients (P = 0.028). There were close associations between CD151 and c-erbB2 overexpression (P = 0.033) and between c-erbB2 and c-Met overexpression (P = 0.001). CD151 overexpression was closely correlated with patient' overall survival (OS; P < 0.001) and disease-free survival (DFS; P < 0.001). Furthermore, the expression rate of CD151 seemed to increase gradually according to the depth of invasion (T stage) (χ(2) test for trend; P = 0.101), N stage (P = 0.238), and pathologic stage (P = 0.153), although trends were not statistically significant. In a multivariate analysis, CD151 overexpression was an independent prognostic factor predicting worse OS (P = 0.002) and DFS (P = 0.005), along with the T and N stage.

CONCLUSIONS

CD151 was found to be an independent prognostic marker for patients with AGC.

Effect of doxorubicin, oxaliplatin, and methotrexate administration on the transcriptional activity of BCL-2 family gene members in stomach cancer cells

Defective apoptosis comprises the main reason for tumor aggressiveness and chemotherapy tolerance in solid neoplasias. Among the BCL-2 family members, whose mRNA or protein expression varies considerably in different human malignancies, BCL2L12 is the one for which we have recently shown its propitious prognostic value in gastric cancer. The purpose of the current work was to investigate the expression behavior of BCL2L12, BAX, and BCL-2 in human stomach adenocarcinoma cells following their exposure to anti-tumor substances. The 3-(4,5-dimethyl thiazol-2-yl)-2,5-diphenyl tetrazolium bromide and trypan blue methods assessed the impact of doxorubicin, oxaliplatin and methotrexate on AGS cells' viability and growth. Following isolation from cells, total RNA was reverse-transcribed to cDNA. Quantification of target genes' expression was performed with real-time PCR using SYBR Green detection system. The relative changes in their mRNA levels between drug-exposed and untreated cells were calculated with the comparative Ct method (2(-ddCt)). All three drugs, as a result of their administration to AGS cancer cells for particular time intervals, provoked substantial fluctuations in the transcriptional levels of the apoptosis-related genes studied. While BAX was principally upregulated, striking similar were the notable changes regarding BCL-2 and BCL2L12 expression in our cellular system. Our findings indicate the growth suppressive effects of doxorubicin, oxaliplatin and methotrexate treatment on stomach carcinoma cells and the implication of BCL2L12, BAX, and BCL-2 expression profiles in the molecular signaling pathways triggered by chemotherapy.

Survival and recurrence free benefits with different lymphadenectomy for resectable gastric cancer: a meta-analysis

BACKGROUND

The objective of the present meta-analysis was to estimate the magnitude of survival and recurrence free benefits from different lymphadenectomy in patients with resectable gastric cancer.

METHODS

A comprehensive search was performed for original studies published from their inception to 2012. Two reviewers independently assessed search results, methodological quality, and data extraction of included studies. Results regarding the overall survival (OS) and recurrence free survival (RFS) in the meta-analysis were expressed as hazard ratios (HR) with 95% confidence intervals (CI).

RESULTS

Twelve randomized control trials (RCTs) were eligible for final meta-analysis. There was not significant difference in OS between D1 and D2 lymphadenectomy (HR = 0.92, 95% CI: 0.77-1.10, P = 0.36), but subgroup analysis of patients without splenectomy and/or pancreatectomy has a trend for OS much more benefiting D2 compared to D1 patients. A significant RFS improvement was found in favor of D2 lymphadenectomy, sensitivity analysis also gives similar fixed effect estimates (HR = 0.68, 95% CI: 0.58-0.81, P = 0.84). There were no significant differences in OS and RFS between D2 group and D3 group (1 trial).

CONCLUSIONS

The present meta-analysis indicates that D2 lymphadenectomy with spleen and pancreas preservation offers the most survival benefit for patients with gastric cancer when done safety.