Multidisciplinary approach to understand the pathogenesis of gastric cancer

A systematic review of computational approaches to understand cancer biology for informed drug repurposing

Cancer is the second leading cause of death globally, trailing only heart disease. In the United States alone, 1.9 million new cancer cases and 609,360 deaths were recorded for 2022. Unfortunately, the success rate for new cancer drug development remains less than 10%, making the disease particularly challenging. This low success rate is largely attributed to the complex and poorly understood nature of cancer etiology. Therefore, it is critical to find alternative approaches to understanding cancer biology and developing effective treatments. One such approach is drug repurposing, which offers a shorter drug development timeline and lower costs while increasing the likelihood of success. In this review, we provide a comprehensive analysis of computational approaches for understanding cancer biology, including systems biology, multi-omics, and pathway analysis. Additionally, we examine the use of these methods for drug repurposing in cancer, including the databases and tools that are used for cancer research. Finally, we present case studies of drug repurposing, discussing their limitations and offering recommendations for future research in this area.

Targeting Tumor Cells with Nanoparticles for Enhanced Co-Drug Delivery in Cancer Treatment

Gastric cancer (GC) is a fatal malignant tumor, and effective therapies to attenuate its progression are lacking. Nanoparticle (NP)-based solutions may enable the design of novel treatments to eliminate GC. Refined, receptor-targetable NPs can selectively target cancer cells and improve the cellular uptake of drugs. To overcome the current limitations and enhance the therapeutic effects, epigallocatechin-3-gallate (EGCG) and low-concentration doxorubicin (DX) were encapsulated in fucoidan and d-alpha-tocopherylpoly (ethylene glycol) succinate-conjugated hyaluronic acid-based NPs for targeting P-selectin-and cluster of differentiation (CD)44-expressing gastric tumors. The EGCG/DX-loaded NPs bound to GC cells and released bioactive combination drugs, demonstrating better anti-cancer effects than the EGCG/DX combination solution. In vivo assays in an orthotopic gastric tumor mouse model showed that the EGCG/DX-loaded NPs significantly increased the activity of gastric tumors without inducing organ injury. Overall, our EGCG/DX-NP system exerted a beneficial effect on GC treatment and may facilitate the development of nanomedicine-based combination chemotherapy against GC in the future.

Interleukin-1β Suppresses Gastrin via Primary Cilia and Induces Antral Hyperplasia

BACKGROUND & AIMS

Helicobacter pylori infection in humans typically begins with colonization of the gastric antrum. The initial Th1 response occasionally coincides with an increase in gastrin secretion. Subsequently, the gastritis segues to chronic atrophic gastritis, metaplasia, dysplasia and distal gastric cancer. Despite these well characterized clinical events, the link between inflammatory cytokines and non-cardia gastric cancer remains difficult to study in mouse models. Prior studies have demonstrated that overexpression of the Hedgehog (HH) effector GLI2 induces loss of gastrin (atrophy) and antral hyperplasia. To determine the link between specific cytokines, HH signaling and pre-neoplastic changes in the gastric antrum.

METHODS

Mouse lines were created to conditionally direct IL1β or IFN-γ to the antrum using the Gastrin-CreERT2 and Tet activator. Primary cilia, which transduces HH signaling, on G cells were disrupted by deleting the ciliary motor protein KIF3a. Phenotypic changes were assessed by histology and western blots. A subclone of GLUTag enteroendocrine cells selected for gastrin expression and the presence of primary cilia was treated with recombinant SHH, IL1β or IFN-γ with or without kif3a siRNA.

RESULTS

IFN-γ increased gastrin and induced antral hyperplasia. However, antral expression of IL1β suppressed tissue and serum gastrin, while also inducing antral hyperplasia. IFN-γ treatment of GLUTAg cells suppressed GLI2 and induced gastrin, without affecting cilia length. By contrast, IL1β treatment doubled primary cilia length, induced GLI2 and suppressed gastrin gene expression. Knocking down kif3a in GLUTAg cells mitigated SHH or IL1β suppression of gastrin.

CONCLUSIONS

Overexpression of IL1β in the antrum was sufficient to induce antral hyperplasia coincident with suppression of gastrin via primary cilia. ORCID: #0000-0002-6559-8184.

Prognostic impact of preoperative prognostic nutritional index in resected advanced gastric cancer: A multicenter propensity score analysis

BACKGROUND

Advanced gastric cancer (AGC) causes debilitating malnutrition and leads to deterioration of the immune response. However, the concept of the prognostic nutritional index (PNI) is controversial when applied to patients with AGC. The aim of the present study was to evaluate the effect of the PNI after gastrectomy in patients with AGC.

MATERIALS AND METHODS

A multicenter retrospective study was conducted using propensity score matching (PSM) in gastric adenocarcinoma patients who underwent resection via laparoscopic or open surgery between 2014 and 2017. To overcome selection bias, we performed 1:1 matching using 5 covariates.

RESULTS

The resection margins (P < 0.001) and LNM (P = 0.004) were significantly different between the two groups. In univariate analysis, poor tumor differentiation (P = 0.038) (R1+R2, P = 0.004), vascular and neural invasion (P < 0.001), and a PNI<50 (P < 0.001) were associated with poor recurrence-free survival (RFS). In multivariate analysis, a PNI<50 (hazard ratio (HR), 12.993; P < 0.001) was a risk factor for RFS. Univariate analysis for overall survival (OS) revealed that a PNI<50 (P < 0.001) (R1+R2,P = 0.006) and vascular and neural invasion (P < 0.001) were risk factors. In subsequent multivariate analysis, a PNI<50 (HR, 24.501; P < 0.001) was a significant risk factor for OS. Clinical assessments performed during a 12.34 (±5.050) month follow-up revealed that OS (P < 0.001) and RFS (P < 0.001) were worse in patients with a low PNI (<50) than in matched patients with a high PNI.

CONCLUSION

A low PNI is a strong predictor of unfavorable RFS and OS in patients with AGC.

Clinical Outcomes of Gastric Cancer Patients Who Underwent Proximal or Total Gastrectomy: A Propensity Score-Matched Analysis

BACKGROUND

Total gastrectomy (TG) and proximal gastrectomy (PG) are used to treat upper-third early gastric cancer. To date, no consensus has been reached regarding which procedure should be selected. The aim of this study was to validate the usefulness of preserving the stomach in early upper-third gastric cancer.

METHODS

Between 2004 and 2013, 201 patients underwent PG or TG at our institution for treatment of upper-third early gastric cancer. According to the defined inclusion and exclusion criteria, 192 cases were enrolled in this study. One-to-one propensity score matching was performed to compare the outcomes between the two groups.

RESULTS

The operation time was shorter in the PG group. Although no significant difference was observed, the PG group had less bleeding and fewer postoperative complications. R0 resection rate was 100%, and no surgery-related deaths were observed. The frequencies of reflux symptoms and anastomotic stenosis were significantly higher in the PG group, but could be controlled by balloon dilation and drug therapy. The maintenance rates of body mass index and lean body mass were significantly higher in patients who underwent PG than TG. The total protein and serum albumin values were higher in the PG group than in the TG group and remained statistically superior.

CONCLUSION

PG group exhibited better perioperative performance. Furthermore, better nutritional results were obtained in the PG group. Although the late stenosis and reflux symptoms must be addressed, the PG is a preferable surgical procedure for the treatment of early proximal gastric cancer.

Proximal gastrectomy versus total gastrectomy for proximal third gastric cancer: total gastrectomy is not always necessary

BACKGROUND

The appropriate extent of gastric resection for patients with proximal third gastric cancer is controversial. This study addresses whether the choice of surgical strategy (proximal gastrectomy [PG] versus total gastrectomy [TG]) influences the outcomes for proximal third gastric adenocarcinoma.

MATERIALS AND METHODS

Review of prospective database at Tata Memorial Hospital from January 2010 to December 2012 identified 343 patients diagnosed and treated for gastric cancer. Of these, 75 underwent curative resections with D2 lymphadenectomy for proximal third gastric adenocarcinoma, which entailed proximal gastrectomy in 43 and total gastrectomy in 32 patients, depending on the epicenter of the primary and its relation with the mid-body of the stomach. Morbidity, lymph node yield, resection margins, patterns of recurrence, and survival were compared between these two groups.

RESULTS

41/75 tumors were pT3 (23 cases [53.4 %] in the PG and 18 cases [56.3 %] in the TG group). Thirty-six patients [83.7 %] in PG and 29 patients [90.6 %] in TG group received neoadjuvant chemotherapy (NACT). There were no significant differences with regard to median blood loss, general complication rates and length of hospitalization between the two groups. The lymph node yield was comparable between the two procedures [PG = 14; TG = 15]. Positive proximal resection margin rates were comparable between the two groups [PG = 4.7 %; TG = 9.4 %], and there was no statistical difference observed in the distal resection margin positivity rates [PG = 4.7 %; TG = 3.1 %]. Regarding the patterns of recurrence, local recurrence in PG was 4.7 % and there was no local recurrence in the TG group (p = 0.08). Distant recurrence rates was dominant in TG [PG = 30.2 % versus TG = 53.1 %]. The overall 2-year survival following PG and TG was 73.8 and 49.9 %, respectively, and not statistically different (p = 0.10).

CONCLUSIONS

The extent of resection for proximal third gastric cancer does not influence the clinical outcome. PG and TG have similar survival rates. Both procedures can be accomplished safely. Therefore, PG should be an alternative to TG, even in locally advanced proximal gastric cancers treated by NACT, provided that the tumor size and location permit preservation of adequate remnant of stomach without compromising oncological resection margins. Future QOL studies would further lend credence to the concept of PG for proximal third gastric cancer.

Combination of preoperative platelet/lymphocyte and neutrophil/lymphocyte rates and tumor-related factors to predict lymph node metastasis in patients with gastric cancer

OBJECTIVE

Lymph node (LN) metastasis is widely accepted as a poor prognosis indicator in patients with gastric cancer. An accurate preoperative prediction of LN status is of crucial importance for the planning treatment. The aim of the present study was to assess the predictive value of the preoperative platelet/lymphocyte (PLR) and neutrophil/lymphocyte rates (NLR) on the LN metastasis in gastric cancer patients and to develop a new preoperative score system to predict LN metastasis.

PATIENTS AND METHODS

A total of 492 operable patients with gastric cancer were enrolled in our study. The clinical utility of the PLR and NLR was evaluated by receiver operating characteristic (ROC) curves. The logistic analysis was used to identify the independent parameters associated with LN metastasis. Then, a score system including those independent parameters that can be detected preoperatively was established, which was also tested by an ROC curve.

RESULTS

The ideal cutoff values for predicting LN metastasis were 1.59 for NLR and 155.67 for PLR according to the ROC curve. Multivariate analyses showed that both PLR and NLR are significantly associated with LN metastasis independent of depth of invasion, lymphatic invasion, macroscopic type, and tumor size. The area under the ROC curve of the score system was 0.830 (95% confidence interval 0.782-0.878), showing a reliable ability to evaluate the status of nodal involvement.

CONCLUSION

Preoperative PLR and NLR are useful biomarkers to predict LN metastasis and the score system in our study may serve as a reliable instrument to predict LN metastasis in gastric cancer patients.

Expression of interleukin 1β in gastric cancer tissue and its effects on gastric cancer

This study detected the expression level of IL-1β in gastric cancer tissue and paracarcinoma tissue, and also analyzed its relationship with clinical and pathological features, so as to explore the expression of IL-1β in gastric cancer tissue and its effect on gastric cancer. A total of 70 fresh primary gastric cancer tumors and corresponding paracarcinoma tissues away from the tumor-incision edge (≥5 cm) were selected from the First Affiliated Hospital of Zhengzhou University from January to December 2014. Total protein concentration was extracted from tissues with radioimmunoprecipitation assay lysis buffer, and IL-1β content in tissues was detected with enzyme-linked immunosorbent assay. The ratio of cell cytokine content and protein concentration was considered as the relative content of cytokines, and the relationship between relative content of cytokines and clinical data was analyzed. Results indicated that the differences in content of IL-1β in gastric cancer tissues and paracarcinoma tissues had no statistical significance, but the content of IL-1β would rise as tumor size was enlarged, based upon analysis (2.9<4.2 ng/g), and the difference was statistically significant (P<0.05). Furthermore, IL-1β content decreased along with differentiation degree and infiltration depth (3.21<4.15 ng/g, 3.06<3.45 ng/g), but the difference was not statistically significant (P>0.05). Therefore, it can be concluded that IL-1β plays an important role in the occurrence and development of gastric cancer and promotes the treatment of gastric cancer to some extent.

Occult gastric cancer presenting as hypoxia from pulmonary tumor thrombotic microangiopathy

Pulmonary tumor thrombotic microangiopathy (PTTM) causing fatal pulmonary hypertension is a rare presentation of malignancy. In general, patients with PTTM rapidly succumb to death due to severe hypoxia. To date, very few cases of PTTM have been reported in the literature; and most of these cases were from gastric cancer and were diagnosed on post mortem autopsy, as it is extremely challenging to make an ante mortem diagnosis. We here report on a case of undiagnosed diffuse gastric cancer, presenting as worsening hypoxia. The clinical, radiographic, and echocardiographic features, and laboratory and pathological results were consistent with PTTM from gastric cancer. The patient was started on anticoagulation therapy, corticosteroids, and high-flow oxygen. However, her hypoxia worsened to the extent that she required ventilator support, and she died soon after intubation due to cardiac arrest. Since diffuse gastric cancer is associated with hereditary diffuse gastric cancer syndrome, cadherin 1 gene mutation analysis was performed to estimate the risk to her daughters. The test came back negative.

Remodeling of the pulmonary artery induced by metastatic gastric carcinoma: a histopathological analysis of 51 autopsy cases

BACKGROUND

Gastric carcinoma remains the second commonest cause of cancer deaths worldwide. Presence of the carcinoma cell in the pulmonary artery is serious condition that might cause remodeling of the pulmonary artery. The present study conducted detailed histopathological analyses to elucidate how gastric carcinoma cells may affect the structure and hemodynamics of pulmonary arteries.

METHODS

Remodeling of the pulmonary artery was assessed based on measurements of arterial diameters and stenosis rates from the autopsies, and their correlation were also validated. We additionally calculated 95 percent confidential intervals (CIs) for the rate of stenosis in groups of pulmonary arteries of different caliber zones (under 100, 100 to 300, and over 300 micrometer). The right ventricular thickness was measured and examined whether it correlated with the rate of pulmonary arterial stenosis.

RESULTS

A total of 4612 autopsy cases were recorded at our institute, among which 168 had gastric carcinoma. Finally, 51 cases of the gastric carcinoma were employed for the study which had carcinoma cells in the lumen of the pulmonary artery. The mean right ventricular wall thickness of these cases was 3.14 mm. There were significant positive associations between the rates of pulmonary arterial stenosis and right ventricular thickness from pulmonary arteries of diameter under 100, 100 to 300, and over 300 micrometer. In these zones, 31, 31, and 33 cases had rates of pulmonary arterial stenosis that were below the lower limit of the 95 percent CI values, respectively. On the other hand, among cases with significant pulmonary stenosis, 17 of 18 cases with stenosis in the over 300 micrometer zone involved pulmonary arteries of both in the under 100 and 100 to 300 micrometer zones.

CONCLUSION

One-third of autopsy with advanced gastric carcinoma had carcinoma cells in lumen of pulmonary artery, but implantation and proliferation may be essential to induce intimal thickening that causes an increasing of pulmonary arterial pressure, because our study revealed a significant positive association between the rate of pulmonary arterial stenosis and right ventricular thickness. In addition, diffuse type gastric carcinoma may be apt to cause the remodeling of the pulmonary artery.

Adenovirus-mediated double suicide gene selectively kills gastric cancer cells

The aim of this study was to evaluate the effect of the adenovirus-mediated double suicide gene (CD/TK) for selective killing of gastric cancer cells. Gastric cancer cells SCG7901 and normal gastric epithelial cell lines were infected by adenoviruses Ad-survivin/GFP and Ad-survivin/CD/TK. GFP expression and CD-TK were detected by fluorescence microscopy and reverse transcriptase polymerase chain reaction (RT-PCR), respectively. After treatment of the infected cells with the pro-drugs ganciclovir (GCV) and/or 5-FC, the cell growth status was evaluated by methyl thiazolyl tetrazolium assay. Cell cycle changes were detected using flow cytometry. In nude mice bearing human gastric cancer, the recombinant adenovirus vector was injected directly into the tumor followed by an intraperitoneal injection of GCV and/or 5-FC. The subsequent tumor growth was then observed. The GFP gene driven by survivin could be expressed within the gastric cancer line SCG7901, but not in normal gastric epithelial cells. RT-PCR demonstrated the presence of the CD/TK gene product in the infected SCG7901 cells, but not in the infected normal gastric epithelial cells. The infected gastric cancer SCG7901, but not the gastric cells, was highly sensitive to the pro-drugs. The CD/TK fusion gene system showed significantly greater efficiency than either of the single suicide genes in killing the target cells (P<0.01). Treatment of the infected cells with the pro-drugs resulted in increased cell percentage in G0-Gl phase and decreased percentage in S phase. In nude mice bearing SCG7901 cells, treatment with the double suicide gene system significantly inhibited tumor growth, showing much stronger effects than either of the single suicide genes (P<0.01). The adenovirus-mediated CD/TK double suicide gene driven by survivin promoter combined with GCV an 5-FC treatment could be an effective therapy against experimental gastric cancer with much greater efficacy than the single suicide gene CD/TK combined with GCV or 5-FC.

Increased Expression of MicroRNA-221 in gastric cancer and its clinical significance

OBJECTIVE

MicroRNA-221 (miR-221), which is located on chromosome X, is an oncogenic microRNA that is involved in several human malignancies. This study aimed to characterize the role of miR-221 in the initiation and malignant progression of gastric cancer.

METHODS

The level of miR-221 expression in 92 pairs of primary gastric tumour tissue and adjacent nontumour tissue was quantified by real-time reverse transcription-polymerase chain reaction. The relationship between the miR-221 level and clinicopathological features was explored.

RESULTS

MiR-221 was up-regulated in 88% (81/92) of gastric cancer tissue samples compared with their paired adjacent nontumour tissue samples. High expression of miR-221 showed a significant correlation with advanced tumour-node-metastasis stage, local invasion and lymphatic metastasis. Univariate and multivariate Cox proportional hazard regression analyses revealed that miR-221 overexpression was an unfavourable prognostic factor for overall survival in patients with gastric cancer.

CONCLUSIONS

These findings suggest that miR-221 is a novel prognostic indicator in gastric cancer and may be a potential target for diagnosis and gene therapy.

Prognostic significance of miR-181b and miR-21 in gastric cancer patients treated with S-1/Oxaliplatin or Doxifluridine/Oxaliplatin

Background

The goal of this study is to evaluate the effectiveness of S-1/Oxaliplatin vs. Doxifluridine/Oxaliplatin regimen and to identify miRNAs as potential prognostic biomarkers in gastric cancer patients. The expression of candidate miRNAs was quantified from fifty-five late stage gastric cancer FFPE specimens.

Experimental Design

Gastric cancer patients with KPS>70 were recruited for the trial. The control group was treated with 400 mg/twice/day Doxifluridine plus i.v. with Oxaliplatin at 130 mg/m²/first day/4 week cycle. The testing group was treated with S-1 at 40 mg/twice/day/4 week cycle plus i.v. with Oxaliplatin at 130 mg/m²/first day/4 week cycle. Total RNAs were extracted from normal and gastric tumor specimens. The levels of miRNAs were quantified using real time qRT-PCR expression analysis.

Results

The overall objective response rate (CR+PR) of patients treated with S-1/Oxaliplatin was 33.3% (CR+PR) vs. 17.6% (CR+PR) with Doxifluridine/Oxaliplatin for advanced stage gastric cancer patients. The average overall survival for patients treated with S-1/Oxaliplatin was 7.80 month vs. 7.30 month with patients treated with Doxifluridine/Oxaliplatin. The expression of miR-181b (P = 0.022) and miR-21 (P = 0.0029) was significantly overexpressed in gastric tumors compared to normal gastric tissues. Kaplan-Meier survival analysis revealed that low levels of miR-21 expression (Log rank test, hazard ratio: 0.17, CI = 0.06–0.45; P = 0.0004) and miR-181b (Log rank test, hazard ratio: 0.37, CI = 0.16–0.87; P = 0.018) are closely associated with better patient's overall survival for both S-1 and Doxifluridine based regimens.

Conclusion

Patients treated with S-1/Oxaliplatin had a better response than those treated with Doxifluridine/Oxaliplatin. miR-21 and miR-181b hold great potential as prognostic biomarkers in late stage gastric cancer.

Increasing the frequency of CIK cells adoptive immunotherapy may decrease risk of death in gastric cancer patients

AIM: To analyze the correlation between cytokine-induced killer (CIK) cells adoptive immunotherapy and cancer-related death in gastric cancer patients.

METHODS: One hundred and fifty-six gastric cancer patients after operation at the Third Affiliated Hospital of Soochow University were enrolled in this study. Their clinical data including demographic characteristics, operation time, tumor size, pathological type and staging, tumor metastasis, outcome of chemotherapy or CIK cells adoptive immunotherapy, survival time or time of death were collected with a standard structured questionnaire. Kaplan-Meier method was used to estimate the median survival time, and the 2- and 5- year survival rates. Hazard risk (HR) and 95% confidence interval (95% CI) of CIK cells adoptive immunotherapy for gastric cancer were calculated using the two-stage time-dependent covariates Cox model.

RESULTS: The survival time of gastric cancer patients was longer after CIK cells adoptive immunotherapy than after chemotherapy (χ² = 10.907, P = 0.001). The median survival time of gastric cancer patients was also longer after CIK cells adoptive immunotherapy than after chemotherapy (49 mo vs 27 mo, P < 0.05). The 2- and 5-year survival rates of gastric cancer patients were significantly higher after CIK cells adoptive immunotherapy than after chemotherapy (73.5% vs 52.6%, 40.4% vs 23.9%, P < 0.05). A significant difference was observed in the survival curve for patients who received CIK cells adoptive immunotherapy (0, 1-10, 11-25, and over 25 frequencies) (χ² = 14.534, P = 0.002). The frequencies of CIK cells adoptive immunotherapy were significantly related with the decreasing risk of death in gastric cancer patients after adjustment for sex and age of the patients, tumor stage and relapse (HR = 0.54, 95% CI: 0.36-0.80) when the first stage Cox model was used to define the subjects who remained alive beyond 36 mo as survivors. However, no correlation was observed between the frequencies of death in CIK cells adoptive immunotherapy and the risk of gastric cancer patients (HR = 1.09, 95% CI: 0.63-0.89) when the second stage Cox model was used to define the subjects who survived for more than 36 mo as survivors.

CONCLUSION: The survival time of the gastric cancer patients treated with chemotherapy combined with CIK cells adoptive immunotherapy is significantly longer than that of the patients treated with chemotherapy alone and increasing the frequency of CIK cells adoptive immunotherapy seems to benefit patients more.

Targeted killing effects of double CD and TK suicide genes controlled by survivin promoter on gastric cancer cell

Suicide genes such as cytosine deaminase (CD) and herpes simplex virus thymidine kinase (TK) encode products that convert nontoxic substances (prodrugs) into toxic metabolites. Studies in recent years indicated that survivin(sur) expression was associated with the biological behaviors of gastric carcinoma. In the present study, targeted killing effects of double CD and TK suicide genes controlled by survivin promoter on gastric cancer cell were investigated, the recombinant pSCT vector containing CD and TK genes driven by sur promoter was constructed and transfected into SGC-7901 cells. After adding the CCV and 5-FC, the effects of double suicide genes on cell growth, cell cycle and proliferation were determined by MTT assay and flow cytometry (FCM). The results showed that sur promoter could specifically drive the expression of double CD/TK gene in SGC-7901 cells, whereas not in the normal GES-1 cell. After using CCV and 5-FC, the growth of SGC-7901 cells was inhibited. G1 phase proportion was significantly higher in SGC-7901 cells transfected with double suicide genes than the untransfected cells. These results suggest that CD and TK double suicide genes driven by sur promoter could provide a new approach for enhancing selective suicide gene therapy of CD/5-FC for the treatment of advanced gastric carcinoma.

Incidence and survival for gastric and esophageal cancer diagnosed in British Columbia, 1990 to 1999

BACKGROUND

Geographical variation and temporal trends in the incidence of esophageal and gastric cancers vary according to both tumour morphology and organ subsite. Both diseases are among the deadliest forms of cancer. The incidence and survival rates for gastric and esophageal carcinoma in British Columbia (BC) between 1990 and 1999 are described.

METHODS

Incidence data for the period 1990 to 1999 were obtained from the BC Cancer Registry. Age-adjusted incidence and survival rates were computed by anatomical subsite, histological type and sex. All rates were standardized to the 1996 Canadian population. The estimated annual percentage change (EAPC) was used to measure incidence changes over time. Kaplan-Meier curves were used to show survival rates, and log-rank tests were used to test for differences in the curves among various groups.

RESULTS

Between 1990 and 1999, 1741 esophageal cancer cases and 3431 gastric cancer cases were registered in BC. There was an increase in the incidence of adenocarcinoma of the esophagus over time (EAPC=9.6%) among men, and of gastric cardia cancer among both women (EAPC=9.2%) and men (EAPC=3.8%). Patients with proximal gastric (cardia) cancer had significantly better survival rates than patients with cancer in the lower one-third of the esophagus. Among gastric cancers, patients with distal tumours had a significantly better survival rate than patients with proximal tumours.

DISCUSSION

The incidences of proximal gastric cancer and esophageal adenocarcinoma are increasing, and their survival patterns are different. Examining these cancers together may elucidate new etiological and prognostic factors.

MG7 mimotope-based DNA vaccination for gastric cancer

Gastric cancer is still one of the leading causes of cancer-related death worldwide. Prevention and treatment of gastric cancer through vaccination has been difficult owing to lack of a specific target and poor immunity. A number of vaccination strategies have been used to augment immune responses against gastric cancer and some progress has been made. In a series of studies, the authors have focused on gastric cancer vaccination approaches based on MG7 mimotopes, which are mimicry epitopes selected from phage-displayed oligopeptide libraries with a gastric cancer cell-specific monoclonal antibody, MG7-Ab. Strategies employed in these studies include viral or plasmid vectors in combination with carrier sequence or unmethylated CpG with synthetic peptides in nanoemulsion. The results demonstrated that MG7 mimotopes could effectively and specifically induce both cellular and humoral immune reactions and in vivo antitumor responses. In particular, a four-MG7 mimotope DNA vaccine was found to elicit much stronger antitumor immune responses in mice compared with its single-mimotope counterpart. These encouraging findings might pave the way for the development of novel MG7 antigen-based vaccination approaches for human gastric cancer. The review also discusses other immune-enhancing vaccination strategies for gastric cancer.

Bovine anti-Helicobacter pylori antibodies neutralize inhibitory effects of SS1 and NCTC11637 antigens on proliferation of Hela cells

AIM: To investigate the inhibitory effects of SS1 and NCTC11637 antigens on the proliferation of Hela cells, and to observe the neutralization of bovine anti-Helicobacter pylori antibodies against SS1 and NCTC11637.

METHODS: The cows were immunized with sonicated Helicobacter pylori (H. pylori) antigen. After the scheduled immunization was completed, the immunization was strengthened with an interval of 1-2 month.The bovine serum was prepared when the ratio in agar-double diffusion was 1:32. The bovine milk was collected at the same time. The serum proteins (81.4g/L) were isolated and purified by saturated ammonium sulfate (500, 330, 330 g/L) and DEAE-32. The obtained proteins were identified by SDS-PAGE. Bovine anti-H. pylori IgGs were incubated with SS1 or NCTC11637, respectively, at 37 ℃ for 2 h, and then added into the solutions including Hela cells. The proliferation of Hela cells was determined by cell growth curve. MTT assay was adopted to evaluate the inhibitory effects of SS1 and NCTC11637 antigens on the proliferation of Hela cells.

RESULTS: The bacterial protein of SS1 and NCTC11637 inhibited the proliferation of Hela cells in a concentration-dependent manner (SS1: r = 0.9 594; NCTC11637: r = 0.9 371), and the cells manifested apoptotic or lysed features. For the same effect, a higher concentration of SS1 was needed. After treatment with bovine anti-H. pylori IgG, the inhibitory effects of SS1 and NCTC11637 on Hela cells were neutralized, and their inhibition rates were negatively related with the concentration of bovine anti-H. pylori IgG (SS1: r = -0.9 936; NCTC11637: r = -0.9 627).

CONCLUSION: SS1 and NCTC11637 can inhibit the proliferation of Hela cells, and bovine anti-H. pylori antibodies can neutralize the inhibiting action in a concentration-dependent manner.