Gut Microbiome Alterations in Cancer and Non-cancer Adults: A Cross-Sectional Metagenomic Study. (1)
Interest in the gut microbiome has exploded over the past decade. We now appreciate that the trillions of microorganisms inhabiting the human gastrointestinal tract are not innocent bystanders but active participants in immune regulation, metabolism, inflammation, and even cancer biology. The study by Hazan and colleagues adds another piece to this rapidly evolving puzzle.
The investigators performed a cross-sectional metagenomic analysis of stool samples from 60 adults, including 20 healthy controls, 15 patients with non-aggressive cancers, and 25 patients with aggressive cancers. Rather than focusing on one cancer type, the study included a broad spectrum of malignancies including breast, colorectal, ovarian, prostate, lymphoma, lung, bladder, thyroid, leukemia, and others.
Major findings
Patients with aggressive cancers demonstrated a characteristic pattern of gut dysbiosis:
Markedly reduced Bifidobacterium
Reduced Faecalibacterium
Reduced Collinsella
Increased Bacteroides
These differences reached statistical significance. Patients with less aggressive cancers showed a similar trend, although most comparisons did not reach significance, likely because of the small sample size.
Perhaps the most striking observation was the profound reduction in Bifidobacterium, falling from approximately 6.5% of the gut microbiome in controls to only 1.2% in aggressive cancers.