Is the colon lining’s microbiome different in cancer?
In 31 CRC patients vs 30 healthy volunteers, tumor mucosa had lower 16S diversity, more Firmicutes and Fusobacteria, and less Proteobacteria; Lactococcus/Fusobacterium rose in tumors while Pseudomonas fell.
Source
Microbiota disbiosis is associated with colorectal cancer
Study at a glance
- Design
- Case-control — 16S V3 pyrosequencing of CRC mucosa vs adjacent tissue vs healthy colonoscopy controls, including proximal vs distal tumors
- N
- N=61 · 31 CRC patients (31 tumor, 20 adjacent; 15 proximal, 16 distal) plus 30 healthy volunteers (15 proximal, 15 distal mucosa); 81 sequenced samples
- Population
- Recently diagnosed CRC patients and healthy colonoscopy volunteers (Shanghai Sixth People's Hospital)
- Outcome
- Mucosa-associated 16S community structure, diversity, and taxon abundances
Structured fields used in claim comparison tables when every cited study has a complete layer.
Inspect source passages
Is the colon lining’s microbiome different in cancer?
These passages occur verbatim in the stored paper text. They support the points listed below; they do not verify every statement in the explanation.
Mean 17,018 reads across 81 samples.
A total of 1,378,458 high-quality and classifiable reads were obtained from this study, with an average of 17,018 ( n = 81) reads per sample.
Shannon 3.43 vs 4.01, P<0.001.
Shannon, 3.43 ± 0.60 vs. 4.01 ± 0.58 (95% CI of the difference, −0.89 to −0.28); P < 0.001
What they did
Pyrosequenced 16S rRNA V3 from 31 CRC tumors, 20 adjacent non-cancerous mucosa, and 30 healthy mucosal samples (proximal and distal), clustering OTUs at 97% identity (mean 17,018 reads/sample).
What they found
Shannon diversity 3.43 vs 4.01 in CRC vs healthy (P<0.001). Firmicutes 63.46% vs 43.36%; Proteobacteria 10.66% vs 60.35%; Fusobacteria 10.58% vs 0.03% (all P<0.001). Tumors vs adjacent: more Firmicutes (P=0.03), less Proteobacteria (P<0.01); Lactococcus 50.85% vs 25.35% (P=0.007).
The limits
What it doesn't show
Cross-sectional mucosa snapshots cannot prove these taxa cause CRC or that probiotics would treat it; relative abundances from V3 454 data are not absolute counts.
Key terms
- Dysbiosis
- Shifted microbial community; here CRC mucosa differed from healthy and from adjacent tissue.
- 16S rRNA V3
- Variable region of bacterial ribosomal RNA used to profile communities by pyrosequencing.
- Fusobacterium
- Genus enriched in CRC mucosa (~10% vs ~0.01% in healthy); linked in other work to inflammation and CRC subsets.
- Firmicutes
- Dominant phylum in CRC mucosa (63%) versus 43% in healthy samples.
- Proteobacteria
- Phylum that dominated healthy mucosa (~60%) but only ~11% of CRC mucosa.
- OTU
- Operational taxonomic unit clustered at 97% 16S similarity; ~1,839 OTUs per sample here.
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People sampled:
Common questions
How many people?
31 CRC patients and 30 healthy volunteers (81 samples).
Shannon diversity?
3.43 ± 0.60 in CRC vs 4.01 ± 0.58 in healthy (P<0.001).
Fusobacteria in CRC vs healthy?
10.58% vs 0.03%.
Lactococcus in tumor vs adjacent?
50.85% vs 25.35% (P=0.007).
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