Mycobacterial infection aggravates Helicobacter pylori-induced gastric preneoplastic pathology by redirection of de novo induced Treg cells

Immuno-oncology-microbiome axis of gastrointestinal malignancy

Research on the relationship between the microbiome and cancer has been controversial for centuries. Recent works have discovered that the intratumor microbiome is an important component of the tumor microenvironment (TME). Intratumor bacteria, the most studied intratumor microbiome, are mainly localized in tumor cells and immune cells. As the largest bacterial reservoir in human body, the gut microbiome may be one of the sources of the intratumor microbiome in gastrointestinal malignancies. An increasing number of studies have shown that the gut and intratumor microbiome play an important role in regulating the immune tone of tumors. Moreover, it has been recently proposed that the gut and intratumor microbiome can influence tumor progression by modulating host metabolism and the immune and immune tone of the TME, which is defined as the immuno-oncology-microbiome (IOM) axis. The proposal of the IOM axis provides a new target for the tumor microbiome and tumor immunity. This review aims to reveal the mechanism and progress of the gut and intratumor microbiome in gastrointestinal malignancies such as esophageal cancer, gastric cancer, liver cancer, colorectal cancer and pancreatic cancer by exploring the IOM axis. Providing new insights into the research related to gastrointestinal malignancies.

Incidence and risk factors of tuberculosis in patients following gastrectomy or endoscopic submucosal dissection: a cohort analysis of country-level data

BACKGROUND

Gastric cancer adversely affects nutrition and immunity, while increasing the risk of tuberculosis (TB). This study investigated the incidence and risk factors for TB in gastric cancer patients who had undergone gastrectomy or endoscopic submucosal dissection (ESD).

METHODS

This retrospective cohort study was conducted using Korean national insurance claims data. We defined three study groups (total gastrectomy, subtotal gastrectomy, and ESD) of patients diagnosed with gastric cancer plus a cancer-free control group. The latent TB infection (LTBI) screening status, TB incidence, and potential confounders in each cohort were analyzed, and the risk of TB was analyzed using a Cox proportional hazard model.

RESULTS

LTBI tests were performed in less than 1% of all patients, and the TB incidence rates were 473.8, 287.4, 199.4, 111.1 events/100,000 person-years in the total gastrectomy, subtotal gastrectomy, ESD, and control cohorts, respectively. Compared to the control cohort, the total gastrectomy cohort showed the highest hazard ratio (HR) for TB incidence (HR: 2.896, 95% CI: 2.559-2.337), while the ESD cohort showed a significantly increased risk (HR: 1.578, 95% CI: 1.957-1.980). Age, body mass index, and lack of exercise were risk factors in all cohorts. Comorbidities were also considered risk factors, depending on the cohort type.

CONCLUSIONS

Patients who underwent gastrectomy or ESD had an increased risk of TB, and this risk was correlated with the scope of gastrectomy. Considering the low rate of LTBI diagnostic tests and increased risk of TB in the study cohorts, more specific and practical guidelines for TB management are required for gastric cancer patients.

FOXP3+ regulatory T cells and the immune escape in solid tumours

FOXP3+ regulatory T (Treg) cells play critical roles in establishing the immunosuppressive tumour microenvironment, which is achieved and dynamically maintained with the contribution of various stromal and immune cell subsets. However, the dynamics of non-lymphoid FOXP3+ Treg cells and the mutual regulation of Treg cells and other cell types in solid tumour microenvironment remains largely unclear. In this review, we summarize the latest findings on the dynamic connections and reciprocal regulations of non-lymphoid Treg cell subsets in accordance with well-established and new emerging hallmarks of cancer, especially on the immune escape of tumour cells in solid tumours. Our comprehension of the interplay between FOXP3+ Treg cells and key hallmarks of cancer may provide new insights into the development of next-generation engineered T cell-based immune treatments for solid tumours.

The Efficacy of Cancer Immunotherapies Is Compromised by Helicobacter pylori Infection

Helicobacter pylori infects the gastric mucosa of a large number of humans. Although asymptomatic in the vast majority of cases, H pylori infection can lead to the development of peptic ulcers gastric adenocarcinoma and mucosa-associated lymphoid tissue (MALT) lymphoma. Using a variety of mechanisms, H pylori locally suppresses the function of the host immune system to establish chronic infection. Systemic immunomodulation has been observed in both clinical and pre-clinical studies, which have demonstrated that H pylori infection is associated with reduced incidence of inflammatory diseases, such as asthma and Crohn’s disease. The introduction of immunotherapies in the arsenal of anti-cancer drugs has revealed a new facet of H pylori-induced immune suppression. In this review, we will describe the intimate interactions between H pylori and its host, and formulate hypothtyeses describing the detrimental impact of H pylori infection on the efficacy of cancer immunotherapies.