Association between gut microbiota and gastric cancers: a two-sample Mendelian randomization study

Area of Science:

• Microbiome research
• Cancer genomics
• Gut health and disease

Background:

• Gastric cancer (GC) is a leading cause of cancer death globally.
• Its etiology involves genetic, dietary, environmental factors, and infections like Helicobacter pylori.
• The role of gut microbiota in GC development is not fully understood.

Purpose of the Study:

• To investigate the causal relationship between gut microbiota and gastric cancer risk.
• To utilize a two-sample Mendelian Randomization (MR) approach for robust analysis.
• To identify specific gut microbial taxa associated with GC development.

Main Methods:

• Employed a two-sample Mendelian Randomization (MR) approach.
• Utilized genome-wide association study (GWAS) summary data from MiBioGen and GC datasets.
• Applied various MR methods (IVW, MR-Egger, weighted median) to assess causal effects.

Main Results:

• Identified protective associations for *Clostridium sensustricto1*, *Actinomycetales*, *Selenomonadales*, *Negativicutes*, and *Rikenellaceae* against GC.
• Found increased GC risk associated with *Roseburia*, *Family XI*, and *Eubacterium brachy group*.
• Results were consistent across MR methods, indicating genuine causal links.

Conclusions:

• Established a genetic-level causal relationship between gut microbiota and gastric cancer.
• Highlighted specific bacterial taxa with protective or risk-associated roles in GC.
• Findings provide a basis for exploring microbiota-targeted GC prevention strategies.