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ORIGINAL RESEARCH article

Front. Microbiol.
Sec. Systems Microbiology
Volume 15 - 2024 | doi: 10.3389/fmicb.2024.1451160
This article is part of the Research Topic The Microbial Link: Exploring Oral and Gut Microbiome Connections View all articles

Unveiling the Hidden Link Between Oral Flora and Colorectal Cancer: A Bidirectional Mendelian randomization analysis and meta-analysis

Provisionally accepted
Zexin Zhang Zexin Zhang 1Wenfeng Wu Wenfeng Wu 1Xiahou Zhikai Xiahou Zhikai 2Yafeng Song Yafeng Song 2*
  • 1 Second Clinical Medical College, Guangzhou University of Traditional Chinese Medicine, Guangzhou, China
  • 2 China Institute of Sport and Health Science, Beijing Sport University, Beijing, China

The final, formatted version of the article will be published soon.

    The impact of oral flora on intestinal micro-environment and related diseases has been widely reported, but its role in colorectal cancer (CRC) remains elusive.Methods: A Two-sample Mendelian Randomization (TSMR) analysis was conducted to explore the causal relationship between oral flora and CRC, with the Inverse-Variance Weighted (IVW) serving as the primary method for evaluating this causal relationship. Data on the oral flora were derived from human samples from the tongue and saliva, with all cohort populations originating from Asia. In addition, 2 independent external cohorts were used to validate the positive results and perform a meta-analysis of the final results. Lastly, to balance the effect of positive oral flora on CRC, a Multivariate Mendelian Randomization (MVMR) analysis was also performed.The TSMR analysis revealed that 17 oral flora may have a causal relationship with CRC in the training cohort. Among them, s Haemophilus, g Fusobacterium, s Metamycoplasma salivarium, and s Mogibacterium pumilum were validated in two testing cohorts. Intriguingly, after integrating the results of the 3 cohorts for meta-analysis, 16 associations remained significant. In the training cohort, MVMR analysis demonstrated that s Capnocytophaga ochracea and s Metamycoplasma salivarium retained statistical significance. In one of the testing cohorts, s Metamycoplasma salivarium, s Streptococcus anginosus, and s Streptococcus sanguinis retained statistical significance. In the other testing cohort, s Metamycoplasma salivarium, s Haemophilus, and g Fusobacterium remained significant. Conclusions: s Haemophilus, g Fusobacterium, s Metamycoplasma salivarium, and s Mogibacterium pumilum have a solid causal relationship with the occurrence and development of CRC.

    Keywords: causal relationship, Oral flora, colorectal cancer, Saliva, Tongue, mendelian analysis, Meta-analysis

    Received: 18 Jun 2024; Accepted: 26 Aug 2024.

    Copyright: © 2024 Zhang, Wu, Zhikai and Song. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

    * Correspondence: Yafeng Song, China Institute of Sport and Health Science, Beijing Sport University, Beijing, 100084, China

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