Mucosal microbial microenvironment in early gastric neoplasia and non‐neoplastic gastric disease

Abstract Background and Aim The biological characterization of microbial environment in early gastric cancer (EGC), other than Helicobacter pylori , is limited. This study aimed to explore the microbial microenvironment in chronic gastritis (CG), fundic gland polyps (FGPs), low‐grade intraepithelial neoplasia (LGIN), and EGC. Methods 16S‐rRNA gene sequencing and bioinformatic analysis were performed on 63 individuals with 252 mucosal biopsies or endoscopic submucosal dissection margin samples from endoscopy. Results The microbiota in gastric LGIN functions analogously to EGC in terms of functional prediction. Neoplastic lesions showed a significant difference to CG or FGPs in beta diversity of the microbiota. Bacteria genera including Paracoccus , Blautia , Barnesiella , Lactobacillus , Thauera , Collinsella were significantly enriched in gastric neoplastic mucosa (LGIN and EGC) compared with non‐neoplastic tissues (CG and FGPs). While Pseudomonas and Kingella were depleted in neoplastic tissues. FGPs showed a distinctive microbial network system that negatively interacted with Helicobacter . Conclusions In terms of the mucosal microbial microenvironment, gastric LGIN and EGC showed no significant difference as early neoplastic lesions. We observed a coordinated microbial microenvironment that correlated negatively with Helicobacter .