Oral Microbiota Associated with Oral and Gastroenteric Cancer

Table 6: Oral bacteria associated with gastric and colorectal cancers

Cancer	Phylum	Genus/species	Main findings	N	Technology used	Case sample	Control sample	Reference
GA	Firmicutes	Streptococcus	Relative abundance increased in GA patients compared to healthy controls	57 newly diagnosed GA, and 80 healthy controls	16S rRNA pyrosequencing	Tongue coating sample from patients	Tongue coating sample from healthy controls	Wu et al., 2018 [⁸³]
CRC	Firmicutes	Streptococcus	Relative abundance increased in CRC patients compared to healthy controls	99 colorectal cancer patients, 32 colorectal polyps patients, and 103 healthy controls	16S rRNA sequencing	Saliva samples from cancer patients	Saliva and faecal samples from controls	Flemer et al., 2017 [⁷⁸]
CRC	Fusobacteria	Fusobacterium			16S rRNA sequencing	Saliva samples from cancer patients	Saliva and faecal samples from controls	Flemer et al., 2017 [⁷⁸]