Alterations of gastric mucosal microbiota across different stomach microhabitats in a cohort of 276 patients with gastric cancerOriginal paper
Karen Pendergrass is a microbiome researcher specializing in microbiome-targeted interventions (MBTIs). She systematically analyzes scientific literature to identify microbial patterns, develop hypotheses, and validate interventions. As the founder of the Microbiome Signatures Database, she bridges microbiome research with clinical practice. In 2012, based on her own investigative research, she became the first documented case of FMT for Celiac Disease, four years before the first published case study.
Read MoreWhat was studied?
This study examined how the gastric mucosal microbiota differs across distinct microhabitats within the stomach in the context of gastric cancer (GC). Researchers compared microbial diversity, composition, bacterial co-occurrence networks, and predicted functional profiles across normal, peritumoral, and tumoral tissue. The goal was to determine whether GC-associated stomach microhabitats, rather than cancer stage or type, shape the gastric microbiota.
Who was studied?
The cohort consisted of 276 patients with gastric cancer who had not received preoperative chemotherapy and were enrolled retrospectively. Tissue samples were collected from three microhabitats: 230 normal, 247 peritumoral, and 229 tumoral samples. Microbial community composition was assessed using 16S rRNA gene sequencing on the MiSeq platform.
What were the most important findings?
The composition and diversity of the gastric microbiota were determined by the specific stomach microhabitat rather than by GC stage or type. Bacterial richness was decreased in both peritumoral and tumoral microhabitats compared to normal tissue, and the co-occurrence network of abundant bacteria was simplified in the tumoral microhabitat. Helicobacter pylori, Prevotella copri, and Bacteroides uniformis were significantly decreased in tumoral tissue, while Prevotella melaninogenica, Streptococcus anginosus, and Propionibacterium acnes were increased there.
What are the greatest implications of this study?
These findings indicate that the tumor microenvironment reshapes the local microbiota in a site-specific manner, with reduced diversity and simplified microbial networks marking the transition from normal to tumoral tissue. The consistent shifts in specific taxa across microhabitats suggest the gastric microbiota could serve as a biomarker of tissue state within the same stomach. This microhabitat-based framework highlights the importance of sampling location when characterizing microbiota changes associated with gastric cancer.