胃癌是中国第二大流行和致命的癌症。微生物群在胃肿瘤发生中发挥重要作用。然而，现有的胃癌微生物标志物研究并没有得出一致的结果。我们检索了PubMed 2005年1月1日至2022年7月18日有关中国患者的16S rRNA测序相关文献，最终获得16篇原创文章。利用α多样性、β多样性和细菌分类群来探索胃微生物群的差异。使用效应大小的线性判别分析和随机森林模型来寻找具有最佳诊断功效的属组合。链球菌属、假单胞菌属、梭杆菌属、硒单胞菌属、消化链球菌属和普氏菌属在胃癌和非胃癌之间表现出显着差异，但单个属在识别胃癌患者方面表现不佳。然而，链球菌属、消化链球菌属、硒单胞菌属、假单胞菌属和普雷沃氏菌属的组合在筛查胃癌方面表现出色，曲线下面积中位数为0.7525（范围：0.5859-0.9350）、0.8818（范围：0.7397-0.9533）、匹配组、不匹配组和其他组中分别为 0.7435（范围：0.7131-0.8483）。因此，结果表明该属组合对胃癌患者具有良好的诊断效果和广泛的适用性，可能为胃癌的无创诊断提供新的线索。重要性 胃癌是中国一个严重且日益严重的健康问题。研究表明，胃癌患者和非癌症患者胃部微生物群存在显着差异，表明微生物群可能在肿瘤发生中发挥作用。在这项荟萃分析中，对现有的16S rRNA微生物数据进行了分析，发现了由5个属组成的组合，在多种类型的样本中区分胃癌和非癌症患者具有良好的功效。这些结果为使用微生物标记物检测胃癌提供了支持。此外，这些生物标志物是进一步研究微生物群在肿瘤发生中的作用的可能候选物。

Gastric cancer is the second most prevalent and deadly cancer in China. Microbiota play an important role in gastric tumorigenesis. However, the available microbial marker studies for gastric cancer do not have consistent results. We searched PubMed for 16S rRNA sequencing in relevant literature on Chinese patients from 1 January 2005 to 18 July 2022, and 16 original articles were finally obtained. Alpha diversity, beta diversity, and bacterial taxa were used to explore the differences in gastric microbiota. Linear discriminant analysis of effect size and a random forest model were used to find the combination of genera with the best diagnostic efficacy. Streptococcus, Pseudomonas, Fusobacterium, Selenomonas, Peptostreptococcus, and Prevotella showed significant differences between gastric cancer and non-gastric cancer, but a single genus performed poorly in identifying patients with gastric cancer. However, a combination of genera Streptococcus, Peptostreptococcus, Selenomonas, Pseudomonas, and Prevotella had excellent performance in screening gastric cancer with the median area under the curve values of 0.7525 (range: 0.5859-0.9350), 0.8818 (range: 0.7397-0.9533), and 0.7435 (range: 0.7131-0.8483) in the Matched, Unmatched, and Other groups, respectively. Therefore, the results indicated that this combination of genera has good diagnostic efficacy and wide applicability for patients with gastric cancer, which may provide new clues for the non-invasive diagnosis of gastric cancer. IMPORTANCE Gastric cancer is a significant and growing health problem in China. Studies have revealed significant differences in gastric microbiota between patients with gastric cancer and non-cancerous patients, suggesting that microbiota may play a role in tumorigenesis. In this meta-analysis, existing 16S rRNA microbial data were analyzed to find combinations consisting of five genera, which had good efficacy in distinguishing gastric cancer from non-cancerous patients in multiple types of samples. These results lend support to the use of microbial markers in detecting gastric cancer. Moreover, these biomarkers are plausible candidates for further mechanistic research into the role of the microbiota in tumorigenesis.