Alterations in Bacterial Community Dynamics from Erosive Gastritis to Gastric Cancer

Microbes have been shown to contribute to gastric carcinogenesis, the knowledge of gastric microbiota alteration in the process of gastric cancer (GC) may provide help in prevention and treatment of GC. Here, the gastric microbiota was investigated by 16S rRNA gene sequencing in gastric juice samples from 60 patients including erosive gastritis (EG), gastric precancerous lesions (GPL) and gastric cancer (GC). The alpha diversity in patients with GC was significantly lower than other groups. And the relative abundance of dominant taxa at phylum level showed a gradual shift trend, such as Firmicutes, Proteobacteria and Treponema. In differential abundance analysis, some bacteria were shown to be down-regulated (e.g., Lautropia and Lactobacillus) and up-regulated (e.g., Peptostreptococcus and Parvimonas). More importantly, Lactobacillus presents closely related to the occurrence and development of GC. Moreover, the microbial interactions and networks in GPL exhibited higher connectivity, higher complexity and lower clustering property compared to other groups, while GC showed the opposite results. Our results suggested that the occurrence of GC was associated to the changes of gastric microbiota.