Table 4: Oral bacteria associated with pancreatic cancers

Cancer	Phylum	Genus/species	Main findings	N	Technology used	Case sample	Control sample	Reference
PC	Bacteroidetes	Porphyromonas gingivalis	Relative abundance associated with a higher risk of PC	361 incident adenocarcinoma of the pancreas, and 371 matching controls	16S rRNA sequencing	Pre-diagnostic oral mouthwash samples from patients	Pre-diagnostic oral mouthwash samples from controls	Fan et al., 2018 [9]
	Fusobacteria	Leptotrichia	Increased relative abundance in PC samples compared to non-PC samples	8 pancreatic cancer patients, 22 healthy controls, and 78 diagnosed with other diseases (including other cancer types)	16S rRNA sequencing	Saliva samples from pancreatic cancer patients	Saliva samples from healthy patients and patients with other diseases	Torres et al., 2015 [75]
PDAC	Firmicutes	Streptococcus	Increased relative abundance in PDAC samples compared to healthy controls	40 newly diagnosed PDAC, and 58 healthy controls	16S rRNA sequencing	Saliva samples from cancer patients	Saliva samples from healthy controls	Olson et al., 2017 [76]
PHC	Actinobacteria	Rothia	Increased relative abundance in PHC samples compared to healthy controls	30 PHC patients, and 25 healthy controls	16S rRNA sequencing	Tongue coating sample from patients	Tongue coating sample from healthy controls	Lu et al., 2019 [77]
	Firmicutes	Peptostreptococcus
	Fusobacteria	Fusobacterium
		Leptotrichia