T cells in gastric cancer: friends or foes

Comprehensive Analysis of Granzymes and Perforin Family Genes in Multiple Cancers

Background/Objectives: Cancer remains a significant global health concern, with immunotherapies emerging as promising treatments. This study explored the role of perforin-1 (PRF1) and granzymes A, B and K (GZMA, GZMB and GZMK) in cancer biology, focusing on their impact on tumor cell death and immune response modulation. Methods: Through a comprehensive genomic analysis across various cancer types, we explored the differential expression, mutation profiles and methylation patterns of these genes, providing insights into their potential as therapeutic targets. Furthermore, we investigated their association with immune cell infiltration and pathway activation within the tumor microenvironment in each tumor type. Results: Our findings revealed distinct expression patterns and prognostic implications for PRF1, GZMA, GZMB and GZMK across different cancers, highlighting their multifaceted roles in tumor immunity. We found increased immune infiltration across all tumor types and significant correlations between the genes of interest and cytotoxic T cells, as well as the most significant survival outcomes in breast cancer. We also show that granzymes and perforin-1 are significantly associated with indicators of immunosuppression and T cell dysfunction within patient cohorts. In skin melanoma, glioblastoma, kidney and bladder cancers, we found significant correlations between the genes of interest and patient survival after receiving immune-checkpoint inhibition therapy. Additionally, we identified potential associations between the mRNA expression levels of these genes and drug sensitivity. Conclusions: Overall, this study enhances our understanding of the molecular mechanisms underlying tumor immunity and provides valuable insights into the potential therapeutic implications of PRF1, GZMA, GZMB and GZMK in cancer treatment.

HOXC12 promotes the invasion and migration of gastric cancer cells by upregulating SALL4 and activating Wnt/β-catenin signaling pathway

BACKGROUND

Gastric cancer is one of the most common malignant tumors in the world, with a poor prognosis. HOXC is a family of transcription factors that are up-regulated in gastric cancer tissues. However, the relationship between Homeobox C12 (HOXC12) and gastric cancer is still unclear.

METHODS

TCGA-STAD and HPA data were analyzed to explore HOXC12 level. Kaplan-Meier Plotter was used to analyze the relationship between HOXC12 level and the prognosis of gastric cancer patients. The HOXC12 was knocked down or overexpressed by shRNA or overexpression vector to explore its functions. Cell migration/invasion assays and wound healing assay were used to assess the invasion/migration ability of gastric cancer cells. Western blot and qPCR were used to detect gene expression and the activation of Wnt/β-catenin signaling pathway. Dual-luciferase reporter assay was used to detect the active region bound by HOXC12 in the promoter of Spalt-like transcription factor 4 (SALL4).

RESULTS

HOXC12 was highly expressed in gastric cancer and was positively correlated with the poor prognosis of gastric cancer patients. HOXC12 promotes the invasion and migration of gastric cancer cells via Wnt/β-catenin signaling pathway. HOXC12 upregulated the transcription of SALL4 by binding to its promoter. HOXC12 was negatively correlated with both the levels of CD8+ T cells and T cell cytotoxicity-related genes.

CONCLUSION

HOXC12 promotes the invasion/migration of gastric cancer cells via SALL4/Wnt/β-catenin axis, and is negatively correlated with the infiltration of CD8+ T cells, suggesting HOXC12 as a diagnostic marker and a potential therapeutic target for gastric cancer.

Dysregulation of systemic immunity and its clinical application in gastric cancer

Immunotherapy has profoundly changed the treatment of gastric cancer, but only a minority of patients benefit from immunotherapy. Therefore, numerous studies have been devoted to clarifying the mechanisms underlying resistance to immunotherapy or developing biomarkers for patient stratification. However, previous studies have focused mainly on the tumor microenvironment. Systemic immune perturbations have long been observed in patients with gastric cancer, and the involvement of the peripheral immune system in effective anticancer responses has attracted much attention in recent years. Therefore, understanding the distinct types of systemic immune organization in gastric cancer will aid personalized treatment designed to pair with traditional therapies to alleviate their detrimental effects on systemic immunity or to directly activate the anticancer response of systemic immunity. Herein, this review aims to comprehensively summarize systemic immunity in gastric cancer, including perturbations in systemic immunity induced by cancer and traditional therapies, and the potential clinical applications of systemic immunity in the detection, prediction, prognosis and therapy of gastric cancer.

Ascites-derived hsa-miR-181a-5p serves as a prognostic marker for gastric cancer-associated malignant ascites

BACKGROUND

Peritoneal carcinomatosis was the main reason leading to gastric cancer (GC)-related death. We aimed to explore the roles of dysregulated microRNAs (miRNAs) and related immune regulation activities in GC-associated malignant ascites.

METHODS

GSE126399 were downloaded from GEO database. Differentially expressed miRNAs in GC ascites samples was firstly screened, and critical miRNAs were further investigated by LASSO (least absolute shrinkage and selection operator) logistic regression and random forest (RF) algorithm. Receiver operating characteristic of critical miRNAs was also constructed. Moreover, functional analysis, immune cell infiltration associated with differentially expressed mRNAs were further analyzed. After selecting key modules by weighted gene co-expression network analysis, mRNAs related with survival performance and transcription factor (TF)-miRNA-mRNA network were constructed.

RESULTS

Hsa-miR-181b-5p was confirmed as critical differentially expressed miRNAs in GC ascites. Then, the tumor samples were divided into high- and low- expression groups divided by mean expression levels of hsa-miR-181b-5p, and subjects with high hsa-miR-181b-5p levels had better survival outcomes. In total, 197 differentially expressed mRNAs associated with hsa-miR-181b-5p levels were obtained, and these mRNAs were mainly enriched in muscle activity and vascular smooth muscle contraction. Hsa-miR-181b-5 was positively related with activated CD4 T cells and negatively related with eosinophil. 17 mRNAs were selected as mRNAs significantly related with prognosis of GC, such as PDK4 and RAMP1. Finally, 75 TF-miRNA-mRNA relationships were obtained, including 15 TFs, hsa-miR-181b-5p, and five mRNAs.

CONCLUSION

Our data suggest that the differentially expressed hsa-miR-181b-5p in ascites samples of GC patients may be a valuable prognostic marker and a potential target for therapeutic intervention, which should be validated in the near future.

Regulatory T cells in gastric cancer: Key controllers from pathogenesis to therapy

Gastric cancer (GC) is a highly aggressive malignancy that remains a significant contributor to cancer-related mortality worldwide, despite a decline in incidence in recent years. Early-stage GC poses a diagnostic challenge due to its asymptomatic nature, leading to poor prognoses for most patients. Conventional treatment approaches, including chemotherapy and surgery, have shown limited efficacy in improving outcomes for GC patients. The advent of immune checkpoint inhibitors (ICIs) has revolutionized cancer therapy, yielding durable responses across various malignancies. However, the clinical benefits of ICIs in GC have been modest, underscoring the need for a comprehensive understanding of immune cell functions within the GC tumor microenvironment (TME). Regulatory T cells (Tregs), a subset of T lymphocytes, play a pivotal role in GC development and progression and serve as prognostic biomarkers for GC patients. This review aims to elucidate the multifaceted roles of Tregs in the pathogenesis, progression, and prognosis of gastric cancer, and establish their actual and future potential as therapeutic targets. By providing insights into the intricate interplay between Tregs and the TME, this review strives to stimulate further investigation and facilitate the development of targeted Treg-based therapeutic strategies for GC.

Prognostic significance and immune characteristics of GPR27 in gastric cancer

Gastric cancer (GC) is one of the most typical cancerous neoplasms occurring in the digestive system. For advanced GC, immunotherapy is the final option for them to prolong survival time. Hence, we aimed to identify new molecular targets to enhance the immunotherapy response in GC individuals. Then we applied bioinformatic analysis to explore the expression profiles of G-protein-coupled receptor 27 (GPR27) transcription and GPR27 methylation. The associations between survival of GC patients and GPR27 transcription and methylation were then analyzed. We also studied the link between GPR27 expression and levels of immune cell infiltration. Finally, we gained insights into the prognostic role of GPR27 protein in 97 cases of GC individuals. According to datasets gained from TCGA, GPR27 mRNA is expressed lower in GC tissues. Down-regulation of GPR27 transcription was related with better survival in GC individuals, and GPR27 cg03024619 had the most significant prognostic value (HR=0.553, P<0.0001). In addition, the expression level of GPR27 has a clear interaction with immune cells' infiltration and their markers. Single-cell analysis displayed that GPR27 is mainly expressed in macrophages. Finally, down-regulation of GPR27 protein was observed in GC tissues and correlated with better survival outcomes. GPR27 can serve as an important prognostic biomarker and exert an immunomodulatory role in GC. Our findings highlight the significance of GPR27 in a variety of cancers, including GC, and provide clues for a better understanding of GPR27 from bioinformatics and clinically validated perspective.

Gastric Cancer and the Immune System: The Key to Improving Outcomes?

Gastric adenocarcinoma is by far the most common form of gastric cancer (GC) and is a highly lethal form of cancer arising from the gastric epithelium. GC is an important area of focus of the medical community, given its often late-stage of diagnosis and associated high mortality rate. While surgery and chemotherapy remain the primary treatments, attention has been drawn to the use of immunologic therapies, which have shown promise in the treatment of other malignancies. The role for immune-based therapies has become clearer as we obtain a greater understanding of the role of the immune system in gastric cancer formation and growth. A variety treatment to augment the immune system are under evaluation in clinical trials, and these include immune checkpoint inhibitors, antibody-drug conjugates, and immune cell-based therapies. Here, we review the immune landscape and immune-based therapies for GC.

The immune microenvironment in gastric adenocarcinoma

Like most solid tumours, the microenvironment of epithelial-derived gastric adenocarcinoma (GAC) consists of a variety of stromal cell types, including fibroblasts, and neuronal, endothelial and immune cells. In this article, we review the role of the immune microenvironment in the progression of chronic inflammation to GAC, primarily the immune microenvironment driven by the gram-negative bacterial species Helicobacter pylori. The infection-driven nature of most GACs has renewed awareness of the immune microenvironment and its effect on tumour development and progression. About 75-90% of GACs are associated with prior H. pylori infection and 5-10% with Epstein-Barr virus infection. Although 50% of the world's population is infected with H. pylori, only 1-3% will progress to GAC, with progression the result of a combination of the H. pylori strain, host susceptibility and composition of the chronic inflammatory response. Other environmental risk factors include exposure to a high-salt diet and nitrates. Genetically, chromosome instability occurs in ~50% of GACs and 21% of GACs are microsatellite instability-high tumours. Here, we review the timeline and pathogenesis of the events triggered by H. pylori that can create an immunosuppressive microenvironment by modulating the host's innate and adaptive immune responses, and subsequently favour GAC development.

Cancer Immunoediting: Elimination, Equilibrium, and Immune Escape in Solid Tumors

Emphasizing the dynamic processes between cancer and host immune system, the initially discovered concept of cancer immunosurveillance has been replaced by the current concept of cancer immunoediting consisting of three phases: elimination, equilibrium, and escape. Solid tumors composed of both cancer and host stromal cells are an example how the three phases of cancer immunoediting functionally evolve and how tumor shaped by the host immune system gets finally resistant phenotype. The elimination, equilibrium, and escape have been described in this chapter in details, including the role of immune surveillance, cancer dormancy, disruption of the antigen-presenting machinery, tumor-infiltrating immune cells, resistance to apoptosis, as well as the function of tumor stroma, microvesicles, exosomes, and inflammation.

Peripheral Cytokine Levels as a Prognostic Indicator in Gastric Cancer: A Review of Existing Literature

Although strong connections exist between the carcinogenesis of gastric cancer and chronic inflammation, gastric cancer is unique in that the chronic gastritis which frequently precedes carcinogenesis is strongly associated with H. pylori infection. The interplay between H. pylori virulence factors and host immune cells is complex but culminates in the activation of inflammatory pathways and transcription factors such as NF-κB, STAT3, and AP-1, all of which upregulate cytokine production. Due to the key role of cytokines in modulating the immune response against tumour cells as well as possibly stimulating tumour growth and proliferation, different patterns of cytokine secretion may be associated with varying patient outcomes. In relation to gastric cancer, interleukin-6, 8, 10, 17A, TNF, and IFN-γ may have pro-tumour properties, although interleukin-10, TNF, and IFN-γ may have anti-tumour effects. However, due to the lack of studies investigating patient outcomes, only a link between higher interleukin-6 levels and poorer prognosis has been demonstrated. Further investigations which link peripheral cytokine levels to patient prognosis may elucidate important pathological mechanisms in gastric cancer which adversely impact patient survival and allow treatments targeting these processes to be developed.

A Panel of Five-lncRNA Signature as a Potential Biomarker for Predicting Survival in Gastric and Thoracic Cancers

Dysfunctional long non-coding RNAs (lncRNAs) have been found to have carcinogenic and/or tumor inhibitory effects in the development and progression of cancer, suggesting their potential as new independent biomarkers for cancer diagnosis and prognosis. The exploration of the relationship between lncRNAs and the overall survival (OS) of different cancers opens up new prospects for tumor diagnosis and treatment. In this study, we established a five-lncRNA signature and explored its prognostic efficiency in gastric cancer (GC) and several thoracic malignancies, including breast invasive carcinoma (BRCA), esophageal carcinoma, lung adenocarcinoma, lung squamous cell carcinoma (LUSC), and thymoma (THYM). Cox regression analysis and lasso regression were used to evaluate the relationship between lncRNA expression and survival in different cancer datasets from GEO and TCGA. Kaplan-Meier survival curves indicated that risk scores characterized by a five-lncRNA signature were significantly associated with the OS of GC, BRCA, LUSC, and THYM patients. Functional enrichment analysis showed that these five lncRNAs are involved in known biological pathways related to cancer pathology. In conclusion, the five-lncRNA signature can be used as a prognostic marker to promote the diagnosis and treatment of GC and thymic malignancies.

Artificial intelligence in gastric cancer: Application and future perspectives

Gastric cancer is the fourth leading cause of cancer-related mortality across the globe, with a 5-year survival rate of less than 40%. In recent years, several applications of artificial intelligence (AI) have emerged in the gastric cancer field based on its efficient computational power and learning capacities, such as image-based diagnosis and prognosis prediction. AI-assisted diagnosis includes pathology, endoscopy, and computerized tomography, while researchers in the prognosis circle focus on recurrence, metastasis, and survival prediction. In this review, a comprehensive literature search was performed on articles published up to April 2020 from the databases of PubMed, Embase, Web of Science, and the Cochrane Library. Thereby the current status of AI-applications was systematically summarized in gastric cancer. Moreover, future directions that target this field were also analyzed to overcome the risk of overfitting AI models and enhance their accuracy as well as the applicability in clinical practice.

Analysis of the expression, function, prognosis and co-expression genes of DDX20 in gastric cancer

DDX20 (DEAD-box polypeptide 20) is implicated in many cellular processes involving alteration of RNA secondary structure. The role of DDX20 in gastric cancer is still unknown. In the research, the expression of DDX20 and the functional roles of DDX20 in gastric cancer were detected. The increased DDX20 expression in gastric cancer tissue compared with normal gastric tissue was observed. Functional experiments indicated that DDX20 promoted gastric cancer MGC-803 and AGS cells growth, migration, and invasion in vitro. Surprisingly, survival analysis showed that high expression of DDX20 is a favorable prognostic factor for patients with gastric cancer. In addition, enrichment analysis revealed that there is a positive correlation between DDX20 expression and T cell activation in gastric cancer. but not in normal gastric tissues. Furthermore, we found that DDX20 expression level has significant positive correlations with activated CD8 + T cells and activated CD4 + T cells in gastric cancer. Therefore, we hypothesize that the prognostic role of DDX20 in gastric cancer patients may be due to patients with high DDX20 expression contained better immune activation. Taken together, these findings suggest that DDX20 can promote the progression of gastric cancer in vitro and its prognostic value in gastric cancer may be related to many factors, including immune activation.

Tumor microenvironment in gastric cancers

The tumor microenvironment favors the growth and expansion of cancer cells. Many cell types are involved in the tumor microenvironment such as inflammatory cells, fibroblasts, nerves, and vascular endothelial cells. These stromal cells contribute to tumor growth by releasing various molecules to either directly activate the growth signaling in cancer cells or remodel surrounding areas. This review introduces recent advances in findings on the interactions within the tumor microenvironment such as in cancer-associated fibroblasts (CAFs), immune cells, and endothelial cells, in particular those established in mouse gastric cancer models. In mice, myofibroblasts in the gastric stroma secrete R-spondin and support normal gastric stem cells. Most CAFs promote tumor growth in a paracrine manner, but CAF population appears to be heterogeneous in terms of their function and origin, and include both tumor-promoting and tumor-restraining populations. Among immune cell populations, tumor-associated macrophages, including M1 and M2 macrophages, and myeloid-derived suppressor cells (MDSCs), are reported to directly or indirectly promote gastric tumorigenesis by secreting soluble factors or modulating immune responses. Endothelial cells or blood vessels not only fuel tumors with nutrients, but also interact with cancer stem cells and immune cells by secreting chemokines or cytokines, and act as a cancer niche. Understanding these interactions within the tumor microenvironment would contribute to unraveling new therapeutic targets.

Pre-treatment Peripheral Neutrophil-Lymphocyte Ratio as a Prognostic Marker in Gastric Cancer

BACKGROUND

Gastric cancer is the fifth cancer worldwide. Inflammatory response increases metastasis through apoptosis inhibition and angiogenesis augmentation. The neutrophil-lymphocyte ratio (NLR), which is a balance between pro-cancer inflammatory and anti-cancer immune responses, was proved as prognostic marker. Peripheral NLR is a good reflection of tumor microenvironment.

METHODS

We retrospectively collected data of gastric and gastro-esophageal cancer patients treated from January 2015 till December 2016. Sixty-one patients were included. Pre-treatment NLR was calculated. We extracted the different clinic-epidemiological and pathological data. Event-free and overall survivals were plotted using Kaplan-Meier curves.

RESULTS

The median age was 55. Male to female ratio was 1:1. Forty-seven patients were smokers. Most of the patients (93.4%) had good performance status (ECOG 0-2). Forty-six patients had gastric and 15 had gastro-esophageal cancer. 50.8% had diffuse gastric type. Grade III represented 49.2% and grade II 46%. Twelve patients had ascites at diagnosis. Stage at presentation was 1.6%, 4.9%, 27.9%, 50.8%, and 14.8% for stage I, II, III, IV, and unknown respectively. The median NLR was 2.4. The NLR showed no significant correlation with different clinic-epidemiologic and pathological variables except presence of ascites; p = 0.046. Median event-free survival (EFS) and overall survival (OS) were 6 and 8 months respectively. High NLR was significantly associated with worse survival; EFS, 5 months vs 8 months (95% CI, p = 0.001). OS, 6 months vs 9 months (95% CI, p = 0.013).

CONCLUSION

Gastric cancer is an aggressive and fatal disease. NLR can be used as a prognostic marker.

Preliminary analysis of single-nucleotide polymorphisms in IL-10, IL-4, and IL-4Rα genes and profile of circulating cytokines in patients with gastric Cancer

Background

Gastric Cancer is highly prevalent and deadly worldwide. In Colombia, it is the most lethal form of cancer. Some single-nucleotide polymorphisms in IL-10, IL-4, and IL-4Rα genes have been associated with an anti-inflammatory environment and a Th2 profile in detriment of the antitumor Th1 response. This research sought to detect single-nucleotide polymorphisms in promoter sequences, like − 1082 (G/A), − 592 (C/A), and − 819 (C/T), as well as − 590 (C/T) of the IL-10 and IL-4 genes, respectively; in addition to the IL-4Rα mutation variants, Ile50Val and Q576R, together with circulating levels of IL-4, TNF-α, IL-10, and IFN-γ in patients with gastric carcinoma in Cúcuta, Colombia.

Methods

In a cross-sectional study, 17 patients and 30 healthy individuals were genotyped for the six polymorphisms mentioned through PCR-RFLP of DNA obtained from peripheral blood cells and serum samples were analyzed by sandwich ELISA to quantify cytokines. Statistical difference between groups was determined along with the association between the presence of polymorphisms and the risk of gastric cancer, as well as the mortality in patients, using Mann-Whitney U test and logistic regression analysis, respectively.

Results

An association between the − 1082 (G/A) and the risk of gastric cancer was found (OR = 7.58, range 0.77–74.06, P = 0.08). Furthermore, patients had a significant increase in IL-4 serum levels (P < 0.01) compared to healthy individuals, both variables showed a higher estimated risk of mortality in patients, although without statistical association (P > 0.05).

Conclusion

We infer that two possible biomarkers (one immunological and one genetic) could be considered in association with gastric cancer in our population, which should be confirmed by subsequent studies involving a greater number of individuals.

Associations between interleukin gene polymorphisms and the risk of gastric cancer: A meta-analysis

Recently, the roles of interleukin-2 (IL-2), IL-4, IL-6 and IL-8 gene polymorphisms in gastric cancer (GC) have been studied extensively, with conflicting results. Therefore, we conducted the present meta-analyses to better elucidate the roles of interleukin gene polymorphisms in GC. Eligible articles were searched in PubMed, MEDLINE, Embase, Web of Science and CNKI. Odds ratios (ORs) and 95% confidence intervals (CIs) were used to detect any potential association between interleukin gene polymorphisms and the risk of GC. A total of 63 case-control studies was finally included in our analyses. Significant associations with the risk of GC were detected for the IL-6 rs1800796 and IL-8 rs4073 polymorphisms in overall analyses. Further subgroup analyses based on ethnicities of participants revealed that the IL-4 rs2243250, IL-6 rs1800796 and IL-8 rs4073 polymorphisms were significantly associated with the risk of GC in Asians. Moreover, IL-8 rs4073 polymorphism was also significantly associated with the risk of GC in Africans. In conclusion, our findings suggested that IL-4 rs2243250, IL-6 rs1800796 and IL-8 rs4073 polymorphisms may serve as genetic biomarkers of GC.

Prognostic potential of an immune score based on the density of CD8+ T cells, CD20+ B cells, and CD33+/p-STAT1+ double-positive cells and HMGB1 expression within cancer nests in stage IIIA gastric cancer patients

OBJECTIVE

There is heterogeneity in the prognosis of gastric cancers staged according to the tumornodes- metastasis (TNM) system. This study evaluated the prognostic potential of an immune score system to supplement the TNM staging system.

METHODS

An immunohistochemical analysis was conducted to assess the density of T cells, B cells, and myeloid-derived suppressor cells (MDSCs) in cancer tissues from 100 stage IIIA gastric cancer patients; the expression of the high-mobility group protein B1 (HMGB1) was also evaluated in cancer cells. The relationship between the overall survival (OS), disease-free survival (DFS), and immunological parameters was analyzed.

RESULTS

An immune score system was compiled based on the prognostic role of the density of T cells, B cells, MDSCs, and the expression of HMGB1 in cancer tissues. The median 5-year survival of this group of patient was 32%. However, the 5-year survival rates of 80.0%, 51.7%, 0%, 5.8%, and 0% varied among the patients with an immune score of 4 to those with an immune score of 0 based on the immune score system, respectively. Similarly, differences in DFS rates were observed among the immune score subgroups.

CONCLUSIONS

An immune score system could effectively identify the prognostic heterogeneity within stage IIIA gastric cancer patients, implying that this immune score system may potentially supplement the TNM staging system, and help in identifying a more homogeneous group of patients who on the basis of prognosis can undergo adjuvant therapy.

Strategies and Advancements in Harnessing the Immune System for Gastric Cancer Immunotherapy

In cancer biology, cells and molecules that form the fundamental components of the tumor microenvironment play a major role in tumor initiation, and progression as well as responses to therapy. Therapeutic approaches that would enable and harness the immune system to target tumor cells mark the future of anticancer therapy as it could induce an immunological memory specific to the tumor type and further enhance tumor regression and relapse-free survival in cancer patients. Gastric cancer is one of the leading causes of cancer-related mortalities that has a modest survival benefit from existing treatment options. The advent of immunotherapy presents us with new approaches in gastric cancer treatment where adaptive cell therapies, cancer vaccines, and antibody therapies have all been used with promising outcomes. In this paper, we review the current advances and prospects in the gastric cancer immunotherapy. Special focus is laid on new strategies and clinical trials that attempt to enhance the efficacy of various immunotherapeutic modalities in gastric cancer.

Helicobacter pylori and T Helper Cells: Mechanisms of Immune Escape and Tolerance

Helicobacter pylori colonizes the gastric mucosa of at least half of the human population, causing a worldwide infection that appears in early childhood and if not treated, it can persist for life. The presence of symptoms and their severity depend on bacterial components, host susceptibility, and environmental factors, which allow H. pylori to switch between commensalism and pathogenicity. H. pylori-driven interactions with the host immune system underlie the persistence of the infection in humans, since the bacterium is able to interfere with the activity of innate and adaptive immune cells, reducing the inflammatory response in its favour. Gastritis due to H. pylori results from a complex interaction between several T cell subsets. In particular, H. pylori is known to induce a T helper (Th)1/Th17 cell response-driven gastritis, whose impaired modulation caused by the bacterium is thought to sustain the ongoing inflammatory condition and the unsuccessful clearing of the infection. In this review we discuss the current findings underlying the mechanisms implemented by H. pylori to alter the T helper lymphocyte proliferation, thus facilitating the development of chronic infections and allowing the survival of the bacterium in the human host.

Helicobacter pylori and T Helper Cells: Mechanisms of Immune Escape and Tolerance

Helicobacter pylori colonizes the gastric mucosa of at least half of the human population, causing a worldwide infection that appears in early childhood and if not treated, it can persist for life. The presence of symptoms and their severity depend on bacterial components, host susceptibility, and environmental factors, which allow H. pylori to switch between commensalism and pathogenicity. H. pylori-driven interactions with the host immune system underlie the persistence of the infection in humans, since the bacterium is able to interfere with the activity of innate and adaptive immune cells, reducing the inflammatory response in its favour. Gastritis due to H. pylori results from a complex interaction between several T cell subsets. In particular, H. pylori is known to induce a T helper (Th)1/Th17 cell response-driven gastritis, whose impaired modulation caused by the bacterium is thought to sustain the ongoing inflammatory condition and the unsuccessful clearing of the infection. In this review we discuss the current findings underlying the mechanisms implemented by H. pylori to alter the T helper lymphocyte proliferation, thus facilitating the development of chronic infections and allowing the survival of the bacterium in the human host.

Tumor-Infiltrating Immune Cells Are Associated With Prognosis of Gastric Cancer

Immune cells contribute to determining the prognosis of gastric cancer. However, their exact role is less clear. We determined the prognostic significance of different immune cells in intratumoral tissue (T), stromal tissue (S), and adjacent normal tissue (N) of 166 gastric cancer cases and their interactions, including CD3+, CD4+, CD8, CD57+, CD68+, CD66b+, and Foxp3+ cells, and established an effective prognostic nomogram based on the immune reactions. We found high densities of TCD3+, TCD4+, TCD8+, SCD3+, SCD4+, SCD57+, SCD66b+, and NFoxp3+ cells, as well as high TCD8+/SCD8+ ratio, TCD68+/SCD68+ ratio, TCD3+/TFoxp3+ ratio, TCD4+/TFoxp3+ ratio, TCD8+/TFoxp3+ ratio, SCD3+/SFoxp3+ ratio, and SCD4+/SCD8+ ratio were associated with better survival, whereas high densities of TCD66b+, TFoxp3+, SFoxp3+ and NCD66b+ cells as well as high TCD57+/SCD57+ ratio, TCD66b+/SCD66b+ ratio, SCD8+/SFoxp3+ ratio, and TFoxp3+/NFoxp3+ ratio were associated with significantly worse outcome. Multivariate analysis indicated that tumor size, longitudinal tumor location, N stage, TCD68+/SCD68+ ratio, TCD8+/TFoxp3+ ratio, density of TFoxp3+ cells, and TCD66b+/SCD66b+ ratio were independent prognostic factors, which were all selected into the nomogram. The calibration curve for likelihood of survival demonstrated favorable consistency between predictive value of the nomogram and actual observation. The C-index (0.83, 95% CI: 0.78 to 0.87) of our nomogram for predicting prognosis was significantly higher than that of TNM staging system (0.70). Collectively, high TCD68+/SCD68+ ratio and TCD8+/TFoxp3+ ratio were associated with improved overall survival, whereas high density of TFoxp3+ cells and TCD66b+/SCD66b+ ratio demonstrated poor overall survival, which are promising independent predictors for overall survival in gastric cancer.

MicroRNA‑34a attenuates the proliferation, invasion and metastasis of gastric cancer cells via downregulation of MET

Proliferation, invasion and metastasis are key features of gastric cancer, contributing to high mortality rates in patients with gastric cancer worldwide. As a direct target of p53, the functions of microRNA (miR)‑34a are important, but controversial, in the progression of gastric cancer. In the present study, the clinical importance of miR‑34a in GC specimens (n=40) were investigated and were confirmed in an independent cohort from The Cancer Genome Atlas (TCGA; n=352). The prognostic value of miR‑34a was analyzed using a Kaplan‑Meier survival curve in the TCGA cohort, in combination with complete follow‑up data (n=157). The level of miR‑34a was detected in the human gastric cancer cell line and normal gastric epithelial cell line. The effect of miR‑34a on proliferation and invasion were evaluated using Cell Counting Kit 8, colony formation and cell invasion assays. The molecular basis of miR‑34a was determined by bioinformatics prediction. The correlation between miR‑34a and MET was assessed using reverse transcription‑quantitative polymerase chain reaction and western blot analyses. The results indicated that miR‑34a was downregulated in the gastric cancer tissues, compared with the normal gastric tissues (P<0.01). miR‑34a was negatively correlated with the depth of invasion and lymph node metastasis of gastric cancer (P<0.01). In the TCGA cohort, the levels of miR‑34a were lower in T3 and T4 tumor stages, compared with the level in the T1 stage, and low levels of miR‑34a predicted significantly longer survival rates in patients with GC (P<0.05). miR‑34a also attenuated the proliferation ability, and inhibited the colony formation and cell invasion abilities of the cells (P<0.01). A negative correlation was observed between miR‑34a and MET in gastric cancer (P<0.01; r=‑0.9526), and >60% of cases exhibited consistent expression of miR‑34a and MET in gastric cancer (P<0.01). In conclusion, miR‑34a was associated with the clinicopathological features of gastric cancer and was a valuable predictor of patient prognosis. miR‑34a acted as a tumor suppressor to inhibit gastric cancer proliferation and invasion via the downregulation of MET.

Immunology and vaccines and nanovaccines for Helicobacter pylori infection

Helicobacter pylori infection is very common worldwide and is an important cause of gastritis, peptic ulcer disease, gastric mucosa-associated lymphoid tissue lymphoma, and gastric adenocarcinoma. Since the eradication requires treatment with multidrug regimens, prevention of primary infection by a suitable vaccine is attractive. Developing vaccines on the spot when and where an infection is breaking out might be possible, thanks to engineered nanoparticles. In this review, the nature of the host immune response to H. pylori infection is considered. We explain recent candidate vaccines and prophylactic or therapeutic immunization strategies for use against H. pylori. We also describe identification of different types of immune responses that may be related to protection against H. pylori infection. Thus, it seems that there is still a strong need to clarify the main protective immune response against H. pylori.

The preoperative lymphocyte to monocyte ratio predicts clinical outcomes in patients with stage II/III gastric cancer

Recently, lymphocyte to monocyte ratio (LMR) has been reported to be associated with clinical outcomes in some types of cancer but has not been explored in gastric cancer. In this study, we analyzed the association between LMR and clinical outcomes in stage II/III gastric cancer patients. Preoperative LMR calculated from peripheral lymphocyte and monocyte with corresponding clinical features from 426 stage II/III gastric cancer patients was noted. Kaplan-Meier method and Cox regression model were applied for overall survival (OS) and recurrence-free survival (RFS). Related with smaller tumor size (p<0.001), increased LMR could predict better OS [hazard ratio (HR), 0.688; 95% confidence interval (CI), 0.521-0.908, p=0.008] and was borderline significantly associated with better RFS (HR, 0.775; 95% CI, 0.592-1.01, p=0.06) in stage II/III gastric cancer patients through multivariable analysis. Subgroup analyses revealed that except stage III patients for RFS which yielded borderline significance (p=0.052), lower LMR was associated with poor clinical outcomes for patients regardless of different stages or whether the patients received adjuvant chemotherapy. The elevated preoperative LMR level was a significant favorable factor in the prognosis of stage II/III gastric cancer patients, especially for those with stage II. However, further validation of our findings is warranted.

Zonal difference and prognostic significance of foxp3 regulatory T cell infiltration in breast cancer

PURPOSE

Forkhead box P3 (Foxp3) is known as the most specific marker for regulatory T lymphocytes, which play an important role in immune tolerance to disturb antitumor immunity. The present study aimed to investigate the prognostic significance of Foxp3 regulatory T lymphocyte (Foxp3 Treg) infiltration in breast cancer.

METHODS

Immunohistochemical studies with Foxp3, CD4, and CD8 were performed on representative full tissue sections from 143 patients with invasive ductal carcinoma, not otherwise specified. Foxp3 Treg infiltration and the ratios between Foxp3 Treg and CD4 or CD8 T cells were separately analyzed for the tumor bed and tumor periphery to evaluate their association with different clinicopathological parameters and patients' outcome.

RESULTS

The tumor periphery was considerably more densely infiltrated by Foxp3 Treg, CD4, and CD8 T cells than the tumor bed. Unfavorable clinicopathological parameters (a Ki-67 labeling index of ≥14%, a worse histologic grade, a worse nuclear grade, hormone receptor negativity, human epidermal growth factor receptor 2 positivity, and tumor recurrence) were associated with increased Foxp3 Treg infiltration and a high ratio between Foxp3 Treg and CD4/CD8 T cells. In the tumor periphery, as Foxp3 Treg infiltration and the Foxp3 Treg/CD8 ratio increased, patients' 5-year disease-free survival rate decreased.

CONCLUSION

The infiltration densities of Foxp3 Treg, CD4, and CD8 T cells were markedly different between the tumor bed and periphery. Besides the absolute count of Foxp3 Treg, the ratio between Foxp3 Treg and effector T cells was a significant prognostic factor in breast cancer.

Loss of p53 attenuates the contribution of IL-6 deletion on suppressed tumor progression and extended survival in Kras-driven murine lung cancer

Interleukin-6 (IL-6) is involved in lung cancer tumorigenesis, tumor progression, metastasis, and drug resistance. Previous studies show that blockade of IL-6 signaling can inhibit tumor growth and increase drug sensitivity in mouse models. Clinical trials in non-small cell lung cancer (NSCLC) reveal that IL-6 targeted therapy relieves NSCLC-related anemia and cachexia, although other clinical effects require further study. We crossed IL-6^-/- mice with Kras^G12D mutant mice, which develop lung tumors after activation of mutant Kras^G12D, to investigate whether IL-6 inhibition contributes to tumor progression and survival time in vivo. Kras^G12D; IL-6^-/- mice exhibited increased tumorigenesis, but slower tumor growth and longer survival, than Kras^G12D mice. Further, in order to investigate whether IL-6 deletion contributes to suppression of lung cancer metastasis, we generated Kras^G12D; p53^flox/flox; IL-6^-/- mice, which developed lung cancer with a trend for reduced metastases and longer survival than Kras^G12D; p53^flox/flox mice. Tumors from Kras^G12D; IL-6^-/- mice showed increased expression of TNFα and decreased expression of CCL-19, CCL-20 and phosphorylated STAT3 (pSTAT3) than Kras^G12D mice; however, these changes were not present between tumors from Kras^G12D; p53^flox/flox; IL-6^-/- and Kras^G12D; p53^flox/flox mice. Upregulation of pSTAT3 and phosphorylated AKT (pAKT) were observed in Kras^G12D tumors with p53 deletion. Taken together, these results indicate that IL-6 deletion accelerates tumorigenesis but delays tumor progression and prolongs survival time in a Kras-driven mouse model of lung cancer. However, these effects can be attenuated by p53 deletion.

Helicobacter pylori CagA: From Pathogenic Mechanisms to Its Use as an Anti-Cancer Vaccine

Helicobacter pylori colonizes the gastric mucosa of more than 50% of the human population, causing chronic inflammation, which however is largely asymptomatic. Nevertheless, H. pylori-infected subjects can develop chronic gastritis, peptic ulcer, gastric mucosa-associated lymphoid tissue lymphoma, and gastric cancer. Chronic exposure to the pathogen and its ability to induce epithelial to mesenchymal transition (EMT) through the injection of cytotoxin-associated gene A into gastric epithelial cells may be key triggers of carcinogenesis. By deregulating cell-cell and cell-matrix interactions as well as DNA methylation, histone modifications, expression of micro RNAs, and resistance to apoptosis, EMT can actively contribute to early stages of the cancer formation. Host response to the infection significantly contributes to disease development and the concomitance of particular genotypes of both pathogen and host may turn into the most severe outcomes. T regulatory cells (Treg) have been recently demonstrated to play an important role in H. pylori-related disease development and at the same time the Treg-induced tolerance has been proposed as a possible mechanism that leads to less severe disease. Efficacy of antibiotic therapies of H. pylori infection has significantly dropped. Unfortunately, no vaccine against H. pylori is currently licensed, and protective immunity mechanisms against H. pylori are only partially understood. In spite of promising results obtained in animal models of infection with a number of vaccine candidates, few clinical trials have been conducted so far and with no satisfactory outcomes. However, prophylactic vaccination may be the only means to efficiently prevent H. pylori-associated cancers.

Activation of STAT3 in human gastric cancer cells via interleukin (IL)-6-type cytokine signaling correlates with clinical implications

Background

The signal transducers and activators of transcription 3 (STAT3) signaling pathway plays important roles in oncogenesis, angiogenesis, immunity, and tumor cell invasion. In the present study, we investigated the association of interleukin (IL)-6/STAT3 signaling pathway with T lymphocytes and clinical implication in patients with gastric cancer.

Methods

Seventy one patients who underwent gastrectomy due to gastric adenocarcinoma were studied. Blood samples were collected before and after surgical gastrectomy to quantify the levels of IL-6, IL-10 and VEGF using an enzyme-linked immunosorbent assay, as well as T lymphocyte subsets (CD3⁺, CD4⁺, CD8⁺, CD4⁺/CD8⁺) and natural killer (NK) cells by a flow cytometry. Furthermore, the expression of IL-6, survivin, STAT3, STAT3 phosphorylation (p-STAT3), and VEGF were determined in human gastric cancer and adjacent normal mucosa through Western blot and immunohistochemistry.

Results

Postoperative levels of IL-6, IL-10 and VEGF in serum were significantly lower than preoperative levels. Percentages of T-cell subsets and NK cells in blood were significantly increased after postoperative-week 1 as compared to preoperative group, which was further augmented at 1 month after gastrectomy. In addition, the expression of IL-6, survivin, STAT3, p-STAT3, and VEGF were increased in human gastric cancer tissues as compared to adjacent normal mucosa. Their expression was associated with TNM stage of gastric cancer. The level of STAT3 activation in clinical samples was correlated with IL-6 expression. All gastric tumor samples, which expressed p-STAT3, also expressed IL-6 with weak expression detected in adjacent normal mucosa.

Conclusion

Increased IL-6-induced activation of STAT3 was observed in neoplastic gastric tissue, which positively correlated with tumor progression. Moreover, IL-6 and STAT3 downstream signals such as IL-10 and VEGF were reduced in patients after removal of gastric cancer as compared to pre-operation. Therefore, inhibition of the IL-6/STAT3 signaling pathway may provide a new therapeutic strategy against gastric cancer.