Meta-analysis of the gut microbiota alterations in patients with gastric cancer in China

Gastric cancer (GC) is one of the most common types of cancer and continues to threaten human health. The microbiota plays an important role in health and disease, including GC. Dysbiosis of gut microbiota has been reported to be associated with various diseases. There are no published meta-analyses of gut microbiota alterations in patients with GC in China. A meta-analysis was performed by searching the PubMed, Web of Science, EMBASE, and Cochrane Library databases up to July 2022. Nine eligible studies, representing 405 patients, were included in the analysis. At the phylum level, Proteobacteria (mean difference 12.46 (3.06–21.87), p ​< ​0.05) was significantly increased, and Firmicutes (mean difference −4.10 (−7.65 to −0.56), p ​< ​0.05) was decreased in patients with GC. At the genus level, Desulfovibrio (mean difference 0.38 (0.16–0.59); p ​< ​0.05) and Streptococcus (mean difference 1.92 (0.37–3.46), p ​< ​0.05) were significantly increased in patients with GC. No significant difference was observed in gut microbial diversity between patients and non-GC controls. Subgroup analysis suggested that region, sample size, and quality of studies caused heterogeneity to different extents. In summary, our study indicated a difference in gut microbial composition between patients with GC and individuals without GC. No significant differences were observed in the diversity of the gut microbes. Changes in the gut microbiota of patients with GC could potentially be used for the non-invasive diagnosis of GC.