Table 1.

Summary of current studies regarding the oral microbiome as non-invasive biomarker for pancreatic cancer.

Year of publication	Authors	Study design	Method	Number of patients	Change in bacterial composition	References
2012	Farrell et al.	Case control	Real-time quantitative PCR of saliva	38 PDAC, 38 HC, 27 CP	Neisseria elongata, Streptococcus mitis	23
2013	Michaud et al.	Prospective population-based	Blood samples, immunoblot array	405 PDAC, 416 HC	Porphyromonas gingivalis ATTC 53978	22
2013	Lin et al.	Pilot study	16S RNA sequencing of oral wash samples	13 PDAC, three CP, 12 HC	Bacteroides increased, Corynebacterium and Aggregatibacter decreased in PDAC	28
2015	Torres et al.	Cross-sectional	16S RNA sequencing and quantitative PCR of saliva	Eight PDAC, 22 HC	Leptotrichia and Porphyromonas increased, Neisseria and Aggregatibacter decreased in PDAC	26
2016	Fan et al.	Case control	16S RNA sequencing of saliva	361 PDAC, 371 HC	Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans increased, Leptotrichia decreased in PDAC	24
2017	Olson et al.	Case control	16S RNA sequencing of saliva	40 PDAC, 39 IPMN, 58 HC	Streptococcus increased, Haemophilus and Neisseria decreased in PDAC	25
2019	Lu et al.	Case control	16S RNA sequencing of tongue swabs	30 PDAC, 25 HC	Leptotrichia, Fusobacterium, Rothia, Actinomyces, Corynebacterium, Atopobium, Peptostreptococcus, Catonella, Filifactor, Campylobacter, Moraxella and Tannerella increased, Haemophilus, Porphyromonas and Paraprevotella decreased in PDAC	29
2020	Vogtmann et al.	Case control	16S RNA sequencing of saliva	273 PDAC, 285 HC	Enterobacteriaceae, Lachnospiraceae G7, Bacteroidaceae or Staphylococcaceae increased and Haemophilus decreased in PDAC	27

CP: chronic pancreatitis; HC: healthy controls; PCR: polymerase chain reaction; PDAC: pancreatic ductal adenocarcinoma; IPMN: intraductal papillary mucinous neoplasm.