Effect of the Interaction between Dietary Patterns and the Gastric Microbiome on the Risk of Gastric Cancer

Association between priori and posteriori dietary patterns and gastric cancer risk: an updated systematic review and meta-analysis of observational studies

An increasing number of epidemiological studies have explored the relationship between the risk of gastric cancer and specific dietary patterns, but the findings remain inconclusive. We, therefore, performed this comprehensive systematic review and meta-analysis to analyze the available evidence regarding the associations between a priori and a posteriori dietary patterns and the risk of gastric cancer. A systematic search of six electronic databases, including PubMed, Web of Science, EBSCO, Scopus, China National Knowledge Infrastructure (CNKI), and Wanfang Data, was carried out to retrieve the relevant articles published up to March 2024. Thirty-six studies (10 cohort and 26 case-control studies) with a total of 2 181 762 participants were included in the final analyses. Combining 15 effect sizes extracted from 12 articles, we observed a reduced risk of gastric cancer in the highest versus the lowest categories of the Mediterranean diet [relative risk (RR), 0.72; 95% confidence interval (CI), 0.61-0.85; P < 0.001]. Combining 11 effect sizes from 10 articles (involving 694 240 participants), we found that the highest Dietary Inflammatory Index scores were significantly associated with an increased risk of gastric cancer (RR, 1.32; 95% CI, 1.11-1.57; P < 0.001). A reduced risk of gastric cancer was shown for the highest compared with the lowest categories of healthy dietary pattern (RR, 0.78; 95% CI, 0.67-0.91; P = 0.002). Conversely, the highest adherence to the Western dietary pattern was associated with an increased risk of gastric cancer (RR, 1.33; 95% CI, 1.19-1.49; P < 0.001). Our study demonstrated that the Mediterranean diet and a healthy dietary pattern were associated with a decreased risk of gastric cancer. Conversely, the Dietary Inflammatory Index and Western dietary pattern were associated with an increased risk of gastric cancer.

Exploring the Link between Helicobacter pylori, Gastric Microbiota and Gastric Cancer

Gastric cancer (GC) still represents one of the leading causes of cancer-related mortality and is a major public health issue worldwide. Understanding the etiopathogenetic mechanisms behind GC development holds immense potential to revolutionize patients' treatment and prognosis. Within the complex web of genetic predispositions and environmental factors, the connection between Helicobacter pylori (H. pylori) and gastric microbiota emerges as a focus of intense research investigation. According to the most recent hypotheses, H. pylori triggers inflammatory responses and molecular alterations in gastric mucosa, while non-Helicobacter microbiota modulates disease progression. In this review, we analyze the current state of the literature on the relationship between H. pylori and non-Helicobacter gastric microbiota in gastric carcinogenesis, highlighting the mechanisms by which microecological dysbiosis can contribute to the malignant transformation of the mucosa.

Inflammation as a Mediator of Microbiome Dysbiosis-Associated DNA Methylation Changes in Gastric Premalignant Lesions

Evidence for the influence of chronic inflammation induced by microbial dysbiosis on aberrant DNA methylation supports a plausible connexion between disordered microbiota and precancerous lesions of gastric cancer (PLGC). Here, a comprehensive study including multi-omics data was performed to estimate the relationships amongst the gastric microbiome, inflammatory proteins and DNA methylation alterations and their roles in PLGC development. The results demonstrated that gastric dysbacteriosis increased the risk of PLGC and DNA methylation alterations in related tumour suppressor genes. Seven inflammatory biomarkers were identified for antrum and corpus tissues, respectively, amongst which the expression levels of several biomarkers were significantly correlated with the microbial dysbiosis index (MDI) and methylation status of specific tumour suppressor genes. Notably, mediation analysis revealed that microbial dysbiosis partially contributed to DNA methylation changes in the stomach via the inflammatory cytokines C-C motif chemokine 20 (CCL20) and tumour necrosis factor receptor superfamily member 9 (TNFRSF9). Overall, these results may provide new insights into the mechanisms that might link the gastric microbiome to PLGC.

Supplementary Information

The online version contains supplementary material available at 10.1007/s43657-023-00118-w.

The Influence of the Microbiome on Immunotherapy for Gastroesophageal Cancer

Immunotherapy has shown promise as a treatment option for gastroesophageal cancer, but its effectiveness is limited in many patients due to the immunosuppressive tumor microenvironment (TME) commonly found in gastrointestinal tumors. This paper explores the impact of the microbiome on the TME and immunotherapy outcomes in gastroesophageal cancer. The microbiome, comprising microorganisms within the gastrointestinal tract, as well as within malignant tissue, plays a crucial role in modulating immune responses and tumor development. Dysbiosis and reduced microbial diversity are associated with poor response rates and treatment resistance, while specific microbial profiles correlate with improved outcomes. Understanding the complex interactions between the microbiome, tumor biology, and immunotherapy is crucial for developing targeted interventions. Microbiome-based biomarkers may enable personalized treatment approaches and prediction of patient response. Interventions targeting the microbiome, such as microbiota-based therapeutics and dietary modifications, offer the potential for reshaping the gut microbiota and creating a favorable TME that enhances immunotherapy efficacy. Further research is needed to reveal the underlying mechanisms, and large-scale clinical trials will be required to validate the efficacy of microbiome-targeted interventions.

Gastric microbiota: an emerging player in gastric cancer

Gastric cancer (GC) is a common cancer worldwide with a high mortality rate. Many microbial factors influence GC, of which the most widely accepted one is Helicobacter pylori (H. pylori) infection. H. pylori causes inflammation, immune reactions and activation of multiple signaling pathways, leading to acid deficiency, epithelial atrophy, dysplasia and ultimately GC. It has been proved that complex microbial populations exist in the human stomach. H. pylori can affect the abundance and diversity of other bacteria. The interactions among gastric microbiota are collectively implicated in the onset of GC. Certain intervention strategies may regulate gastric homeostasis and mitigate gastric disorders. Probiotics, dietary fiber, and microbiota transplantation can potentially restore healthy microbiota. In this review, we elucidate the specific role of the gastric microbiota in GC and hope these data can facilitate the development of effective prevention and therapeutic approaches for GC.

Dynamic variations of the gastric microbiota: Key therapeutic points in the reversal of Correa's cascade

Correa's cascade is a dynamic process in the development of intestinal-type gastric cancer (GC), and its pathological features, gastric microbiota and interactions between microorganisms and their hosts vary at different developmental stages. The characteristics of cells, tissues and gastric microbiota before or after key therapeutic points are critical for monitoring malignant transformation and early tumour reversal. This review summarises the pathological features of gastric mucosa, characteristics of gastric microbiota, specific microbial markers, microbe-microbe interactions and microbe-host interactions at different stages in Correa's cascade. The markers related to each Correa's cascade point were analysed in detail. We attempted to identify key therapeutic points for early cancer reversal and provide a novel approach to reduce the incidence of GC and improve precise treatment.

The Association Between the Gut Microbiome, Nutritional Habits, Antibiotics, and Gastric Cancer: a Scoping Review

 PURPOSE OF REVIEW: Gastric cancer (GC) represents one of the leading causes of cancer-related deaths worldwide. The prevalence of GC among the younger population has been increasing in recent years, and the latter is associated with late detection and advanced disease status. The factors involved in the development of GC have been the focus of investigation in the past few years; yet no consistent conclusions or preventative solutions have been suggested. This scoping review aims to explore and report on research studies conducted to investigate the association between GC, the gut microbiome, and nutritional habits. RECENT FINDINGS : Using a predefined protocol in compliance with the PRISMA guidelines, a search was conducted on four separate databases including Google Scholar, Cochrane Library, ProQuest, and PubMed to investigate the association between GC, microbiome, and nutrition. A total of 1219 articles were identified through this process. Forty-three articles met the initial screening criteria and following full-article analysis, and 10 articles met the full inclusion criteria and were included in the current review. The results of the study support that there are differences in the gut microbiota between GC patients and healthy controls and that GC patients may have increased microbiota richness and lower diversity compared to healthy controls. In addition, the detection of pre/early GC may be possible through the analysis of the microbiota using fecal sampling. Nutritional habits, probiotics, and antibiotics may also play an important role in affecting GC development. Preliminary studies support a role for the gut microbiota in developing GC. Yet, the lack of sufficient randomized controlled studies investigating the association between GC, the gut microbiota, and nutritional habits demonstrates the need for further clinical research to develop preventative strategies that will aim to reduce the increased incidence of GC among all age groups including younger populations.