Gut Microbiome Alterations in Cancer and Non-cancer Adults: A Cross-Sectional Metagenomic Study

IntroductionPrevious studies found associations between cancer and the gut microbiome. Thus, we aimed to investigate the gut microbiome composition in adults with and without cancer to try to identify specific microbes that may be associated with cancer in a cross-sectional, observational, and retrospective study.MethodsStool samples from sixty participants, n=20 controls, n=25 with aggressive cancer, and n=15 with non-aggressive cancer were analyzed using Metagenomic Next Generation Sequencing. Mann-Whitney U test tests were used to examine differences in the relative abundances of bacterial genera.ResultsCompared to controls, aggressive cancer patients had statistically significantly lower levels of gut Bifidobacterium, Faecalibacterium, and Collinsella, (all p≤0.05), while they had higher levels of gut Bacteroides (p=0.015). Non-aggressive cancer patients had lower levels of gut Bifidobacterium compared to controls, an association that was approaching statistical significance (p=0.054).ConclusionAggressive-cancer patients showed significantly altered levels of key gut microbes compared to controls. These are preliminary associations, and thus further larger studies are needed to confirm these findings.