Metagenomic analysis of gut microbiota in colorectal adenocarcinoma in the MENA region

Abstract

Background: Growing evidence suggests that gut microbiota plays a role in the development of colorectal cancer (CRC), and a few bacterial strains have been linked to carcinogenesis. Contrary to the Western population, the relationship between pro-cancer microorganisms and CRC among Middle Eastern individuals remains largely unexplored. Ninety-eight samples from Middle Eastern individuals with and without CRC were subjected to microbial profiling based on the 16S rRNA gene.

Results: The CRC group exhibited a more complex gut microbiota with clusters that were significantly distinct from those of the control group. The taxonomic orders Caulobacterales, Rhizobiales, Sphingomonadales, and Burkholderiales, along with the genera Recibecterium and Sphingobium, were overrepresented in the CRC samples based on differential abundance testing between the CRC and control groups. Utilizing 16S-based functional prediction, we identified a significant enrichment of pathways vital for pentose and glucuronate interconversions, metabolism of terpenoids and polyketides, spliceosome, and dTMP kinase pathways within the CRC group. Moreover, we observed a link between Herbaspirillum huttiense and the pathways regulating the actin cytoskeleton; this intriguing connection may provide insights into the molecular mechanisms underlying cytoskeletal rearrangement and carcinogenesis triggered by H. huttiense.

Conclusions: The findings of this study support the connection between gut microbiota and the development of CRC and highlight region-specific microbial signatures that may serve as non-invasive diagnostic biomarkers or predictive tools for early screening in Middle Eastern populations, where CRC is increasingly diagnosed at advanced stages. These insights could inform the development of microbiome-based screening panels and personalized prevention strategies adapted to the MENA region's unique genetic, dietary, and environmental profiles.

Keywords: adenocarcinoma; colorectal cancer; dysbiosis; metagenomics; microbiota.