The human gut holds the densest microbiome ecosystem essential in maintaining healthy host physiology, whereby disruption of this ecosystem has been linked to the development of colorectal cancer (CRC). Accordingly, 16S rRNA sequencing studies on CRC gut mucosal tissues have found bacteria such as Fusobacterium nucleatum and Bacteroides fragilis to be over-represented in CRC patients from various regions in the world. As CRC is one of the most common malignancies in Malaysia, this study was carried out to profile the gut microbiome and identify over-represented bacteria in Malaysian CRC patients.Methods
This study was carried out from 2014 till 2017, where a total of 18 CRC patients and 18 healthy controls from UKM Medical Centre, Kuala Lumpur, Malaysia were included. 16S rRNA sequencing of gut mucosal tissue samples targeting the 16S rRNA V3/V4 regions was performed with an Illumina MiSeq(R) sequencer, while diversity analyses were carried out using QIIME to determine differences between gut mucosal microbiome profile of CRC patients compared to healthy controls.Results
We observed a significant difference in gut mucosal microbiome composition of CRC patients compared to healthy controls. Higher relative abundance of Fusobacteria and Verrucomicrobia phyla were detected. Further linear discriminant analysis (LDA) effect size analysis showed significant enrichment of Fusobacterium, Parvimonas, Akkermansia and Peptostreptococcus genera in CRC patients. Interestingly, these bacterial genera were found to be enriched in all CRC cases of this study, regardless of patient demographics and CRC staging.Conclusions
In summary, we successfully characterised the gut mucosa-associated microbiome of Malaysian CRC patients. Significant abundance of Fusobacterium, Parvimonas, Akkermansia, and Peptostreptococcus in these patients indicates the importance of these genera towards colorectal carcinogenesis. Nevertheless, a larger study to test the reproducibility of these results will be crucial before these bacteria could be utilised as screening biomarkers for CRC in Malaysians.