Causal relationship between gut microbiota and hepatocellular carcinoma: a two-sample Mendelian randomization and case-control study.

backgroundAccumulating evidence from both observational studies and clinical trials has established a connection between the gut microbiome and hepatocellular carcinoma (HCC). Nevertheless, the causal relationship between gut microbes and hepatocellular carcinoma remains ambiguous.

methodsThe principal study method employed was Mendelian randomization (MR). The exposure group included 7738 samples from the MiBioGen Consortium Gut Microbiota Genome-Wide Association Study (GWAS), whereas the outcome group included 8,885,115 single nucleotide polymorphisms (SNPs) from the IEU OpenGWAS project database of hepatocellular carcinoma (HCC). Utilizing the MR-Egger regression, weighted median (WME), and weighted mode (WM) as supplemental methods for inverse variance weighting (IVW), the main basis was IVW. Additional sensitivity, pleiotropy, and heterogeneity tests were performed. To confirm the MR results, sequencing data from a case-control study were used. We enrolled 29 patients with HBV-HCC who were hospitalized at Tianjin Second People's Hospital between October 2022 and August 2023, and chose 21 healthy employees as controls.

resultsIVW analysis showed that gut Clostridia (OR = 0.554, 95%CI: 0.361-0.850, p = 0.007), Clostridiales (OR = 0.554, 95%CI: 0.361-0.850, p = 0.007), and Dorea (OR = 0.679, 95%CI: 0.479-0.964, p = 0.030) were protective factors against HCC. Gut Desulfovibrio piger (OR = 1.304, 95%CI: 1.080-1.499, p = 0.004), Bacteroides ovatus (OR = 1.304, 95%CI: 1.046-1.626, p = 0.018), Bacteroides stercoris (OR = 1.714, 95%CI: 1.183-2.483, p = 0.004), and Paraprevotella xylaniphila (OR = 1.256, 95%CI: 1.003-1.573, p = 0.047) were risk factors for HCC. A case-control study demonstrated that the relative abundances of gut Clostridia, Clostridiales, and Dorea were significantly higher in healthy controls than in patients with HCC. Conversely, the relative abundance of Bacteroides stercoris was lower in healthy controls than in patients with HCC.

conclusionThis study showed that gut Clostridia, Clostridiales, and Dorea were associated with a reduced risk of HCC, whereas gut Bacteroides stercoris was the exact opposite.

conclusionThis study demonstrated that gut Clostridia, Clostridiales, and Dorea were linked to a decreased HCC risk, while gut Bacteroides stercoris was linked to an increased HCC risk.