Metabolic and functional pathways of gut microbiota in patients with gastric cancer: The DELIVER trial (JACCRO GC-08)

We analyzed the differences in bacterial composition between 475 Japanese patients with advanced gastric cancer (median age 70 years, median BMI 20.0) and 106 healthy individuals using a comprehensive metagenome shotgun analysis. Among the patients with advanced gastric cancer, 71% were male, 37.% patients had relapsed, and 55.5% previously underwent gastrectomy. Bifidobacterium , Anaerostipes , and Parabacteroides were predominant in healthy individuals, whereas Streptococcus , Lactobacillus , and Odoribacter were predominant in patients with advanced gastric cancer. Additionally, Kyoto Encyclopedia of Genes and Genomes pathway analysis showed that butanoate and pyruvate metabolism was enriched in healthy individuals, whereas factors such as ABC transporters and ribosomes were enriched in patients with advanced gastric cancer. Clustering analysis broadly classified patients with advanced gastric cancer and healthy individuals into two clusters; however, clustering using pathway data enabled a clearer classification of patients with advanced gastric cancer and healthy individuals than clustering using flora analysis. Moreover, healthy individuals showed higher bacterial flora diversity than patients with advanced gastric cancer. Thus, we successfully identified the molecular characteristics of microbial genera and functional pathways in the gut of patients with advanced gastric cancer. Our results suggest that fecal metagenomic shotgun sequencing analysis can be used to detect gastric cancer.