Table 1.

Studies on the association between microbiota and pancreatic cancer.

Study author, year of publication	Sample size (Tumor group vs non-tumor group)	Microbiome specimen	Microbial alterations (increases)	Microbial alterations (decreases)	Significance
Fan et al., 2018 (37)	361, 371	Oral wash samples	P. Gingivalis, A. actinomycetemcomitans	Fusobacteria, Leptotrichia	Increased risk of PC
Risch et al., 2010 (40)	373, 690	Serum	H pylori		Increased risk of PC
Pushalkar et al., 2018 (14)	32, 31	Fecal and PDA	Proteobacteria, Synergistetes, Euryarchaeota, Bacteroidetes, Firmicutes		Increased risk of PC
Aykut et al., 2019 (15)	13, 5	Fecal and PDA	Ascomycota, Basidiomycota, Malassezia		Increased risk of PC and promoted tumor progression
Mei et al., 2018 (43)	14, 14	Bile	Enterococcus, Streptococcus, Shigella, Veroella, Enterobacter		Increased risk of PC
Mei et al., 2018 (43)	14, 14	Duodenal mucosa	Acinetobacter, Aquabacterium, Oceanobacillus, Rahnella, Massilia, Delftia, Deinococcus, Sphingobium		Increased risk of PC
Gaiser et al., 2019 (39)	14, 8	IPMN	Firmicutes, Proteobacteria		Increased risk of PC and promoted tumor progression
Geller et al., 2017 (12)	113, 20	PDAC	Enterobacteriaceae, Pseudomonadaceae		Increased drug resistance
Riquelme et al., 2019 (48)	22, 21	PDAC	Pseudoxanthomonas, Streptomyces, Saccharopolyspora, Bacillus clausii		Predicted long-term survivor