该研究旨在通过对病例对照研究的综合评估，系统地确定在胃癌中观察到的肠道微生物群的变化。我们对 PubMed、Embase、Cochrane Library 和 Web of Science 进行了系统文献检索，以确定以下病例对照研究：比较了患有和未患有胃癌的个体的微生物组。纳入研究的质量采用纽卡斯尔-渥太华质量评估量表（NOS）进行评估。荟萃分析利用随机效应模型，并进行亚组和敏感性分析以评估研究异质性。所有数据分析均使用 Stata 17.0 中的“metan”软件​​包进行，结果使用对数比值比 (log OR) 和 95% 置信区间 (CI) 进行描述。共有 33 项研究涉及 4,829 名参与者，符合以下条件进行分析： 29 项研究提供了 α 多样性的变化，18 项研究报告了 β 多样性。荟萃分析显示，只有香农指数显示α-多样性具有统计显着性[-5.078（-9.470，-0.686）]。在门水平上没有观察到显着差异，而在属水平上发现了11种细菌发生显着变化，例如乳酸菌[5.474，（0.949，9.999）]和链球菌[5.095，（0.293，9.897）]增加，而属水平减少卟啉单胞菌与Rothia相同[-8.602,(-11.396,-5.808)]。敏感性分析表明9个细菌属的变化较为稳健。对各国的亚组分析显示，韩国胃癌患者的螺杆菌和链球菌丰度不断增加，而葡萄牙胃癌患者的奈瑟菌数量却有所减少。关于样本来源，该研究观察到胃癌患者胃粘膜中的乳酸菌和类杆菌以及螺杆菌和链球菌均有所增加。然而，与非胃癌组相比，拟杆菌属的相对丰度有所下降，这在粪便样本中得到了体现。这项研究发现了胃癌患者中 9 个细菌属的显着变化，这些变化因国家/样本来源而异。需要进行大规模研究来探索这些变化背后的机制。唯一标识符：CRD42023437426 https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42023437426。版权所有 © 2024 张吴鞠、王、刘、朱。

The study aims to systematically identify the alterations in gut microbiota that observed in gastric cancer through comprehensive assessment of case-control studies.The systematic literature search of PubMed, Embase, Cochrane Library, and Web of Science was conducted to identify case-control studies that compared the microbiomes of individuals with and without gastric cancer. Quality of included studies was evaluated with the Newcastle-Ottawa Quality Assessment Scale (NOS). Meta-analyses utilized a random-effects model, and subgroup and sensitivity analyses were performed to assess study heterogeneity. All data analyses were performed using the "metan" package in Stata 17.0, and the results were described using log odds ratios (log ORs) with 95% confidence intervals (CIs).A total of 33 studies involving 4,829 participants were eligible for analysis with 29 studies provided changes in α diversity and 18 studies reported β diversity. Meta-analysis showed that only the Shannon index demonstrated statistical significance for α-diversity [-5.078 (-9.470, -0.686)]. No significant differences were observed at the phylum level, while 11 bacteria at genus-level were identified significant changed, e.g., increasing in Lactobacillus [5.474, (0.949, 9.999)] and Streptococcus [5.095, (0.293, 9.897)] and decreasing in Porphyromonas and Rothia with the same [-8.602, (-11.396, -5.808)]. Sensitivity analysis indicated that the changes of 9 bacterial genus were robust. Subgroup analyses on countries revealed an increasing abundance of Helicobacter and Streptococcus in Koreans with gastric cancer, whereas those with gastric cancer from Portugal had a reduced Neisseria. Regarding the sample sources, the study observed an increase in Lactobacillus and Bacteroides in the gastric mucosa of people with gastric cancer, alongside Helicobacter and Streptococcus. However, the relative abundance of Bacteroides decreased compared to the non-gastric cancer group, which was indicated in fecal samples.This study identified robust changes of 9 bacterial genus in people with gastric cancer, which were country-/sample source-specific. Large-scale studies are needed to explore the mechanisms underlying these changes.Unique Identifier: CRD42023437426 https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42023437426.Copyright © 2024 Zhang, Wu, Ju, Wang, Liu and Zhu.