Table 1.
Overview of the major gut microbiota studies involving pancreatic cancer.
| Study | Study design | Microbiome specimen | Detection method | Microbial change | Author conclusion |
|---|---|---|---|---|---|
| Michaud et al. (Michaud et al., 2013) | Prospective cohort study | Plasma | Antibiotics to oral bacteria | ↑Porphyromonas gingivalis (ATTC 53978) | Twofold higher risk of PC among individuals with high levels of antibodies against P. gingivalis |
| Fan et al. (Fan et al., 2018) | Case-control | Oral | 16S sequencing | ↑Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans, ↓Fusobacteria and Leptotrichia | Presence of oral microbiota are related to increased risk of PC. Decreased relative abundance of Fusobacteria and Leptotrichia are associated with subsequent risk of PC |
| Jesnowski et al. (Jesnowski et al., 2010) | Case-control | Pancreas | 16S sequencing | NA | H. pylori cannot trigger PC directly |
| Armougom et al. (Armougom et al., 2009) | Case-control | Feces | qPCR | ↑Lactobacillus,↓Bacteroidetes, ↑Methanobrevibacter smithii | Lactobacillus increases in some obese patients and M. smithii increases in anorexic patients |
| Larsen et al. (Larsen et al., 2010) | Case-control | Feces | qPCR | ↑Betaproteobacteria, ↓Firmicutes and Clostridia | Patients with type 2 diabetes is associated with compositional changes in gut microbiota |
| Jandhyala et al. (Jandhyala et al., 2017) | Case-control | Feces | 16S sequencing | ↓Faecalibacterium prausnitzii and Ruminococcus bromii | The gut microbiota altered in patients with chronic pancreatitis, especially in patients with diabetes |
| Torres et al. (Torres et al., 2015) | Cross-sectional | Salivary | 16S sequencing | ↑Leptotrichia, ↓Porphyromonas | The ratio of Leptotrichia to Porphyromonas in the saliva may be used as a biological marker of PC |
| Nilsson et al. (Nilsson et al., 2006) | Case-control | Pancreas | DNA sequencing | NA | Gastric and enterohepatic Helicobacter species suggest a possible role in the development of chronic pancreatitis and PC |
| Mitsuhashi et al. (Mitsuhashi et al., 2015) | Case-control | Pancreas | qPCR RT-PCR | NA | Fusobacterium species may be a prognostic biomarker of PC |
| Riquelme et al. (Riquelme et al., 2019) | Cohort study | Pancreas | 16S sequencing | ↑Alpha diversity; ↑Saccharopolyspora, Pseudoxanthomona, Streptomyces, Bacillus clausii | The tumor microbiome diversity can determine the survival of PDAC patients |
| Sivan et al. (Sivan et al., 2015) | Pilot | Feces | 16S sequencing | ↑Bifidobacterium (OTU_681370) | Bifidobacterium promotes T-cell mediated antitumor immunity and activates anti-PD-L1 efficacy |
PC, pancreatic cancer; PDAC, pancreatic ductal adenocarcinoma; NA, not applicable; qPCR, quantitative PCR; RT-PCR, reverse transcription PCR; OTU, operational taxonomic unit; PD-L1, programmed cell death-ligand 1.
↑: number increased; ↓: number decreased.