Table 2.

Oral organisms associated with gastric cancer (GC).

Subject	Organisms (Oral Bacteria)	Sample Type	Reference
293 patients included superficial gastritis (SG; n = 101), atrophic gastritis (AG; n = 93), and gastric cancer (GC; n = 99).	The proportions of presumed proinflammatory taxa, including Corynebacterium and Streptococcus were higher in the disease group than they were in the control group.	saliva sample	[66]
81 cases including SG, AG, intestinal metaplasia (IM) and GC from Xi’an, China.	Oral bacteria such as Peptostreptococcus stomatis, Streptococcus anginosus, Parvimonas micra, Slackia exigua and Dialister pneumosintes were enriched in cancerous tissues.	gastric mucosal samples	[67]
62 GC patients who underwent subtotal gastrectomy at The First Hospital of China Medical University.	Oral bacteria such as Fusobacterium, Streptococcus, Peptostreptococcus, and Prevotella were enriched in cancerous tissues.	gastric tissue samples	[68]
37 individuals with GC and 13 controls.	The proportions of Veillonella, Prevotella, Aggregatibacter, and Megasphaera increased were higher in the disease group than they were in the control group, while the proportions of Leptotrichia, Rothia, Capnocytophaga, Campylobacter, Tannerella and Granulicatella were lower.	saliva and plaque samples	[69]
57 newly diagnosed gastric adenocarcinomas and 80 healthy controls.	The proportion of Firmicutes was higher in the disease group than it was in the control group, while the proportion of Bacteroidetes was lower.	tongue coating sample	[70]
78 gastritis patients and 50 healthy individuals.	The proportion of Campylobacter concisus was higher in the disease group than it was in the control group.	tongue-coating samples	[71]
165 GC cases and 323 matched controls from Asian, African American, and European American populations.	The proportions of Neisseria mucosa and Prevotella pleuritidis were higher in the disease group than they were in the control group, while the proportions of Mycoplasma orale and Eubacterium yurii were lower.	pre-diagnostic buccal samples	[72]
12 GC cases and 20 matched controls (functional dyspepsia) in Singapore and Malaysia.	Oral bacteria such as Lactococcus, Veilonella, and Fusobacteriaceae (Fusobacterium and Leptotrichia) were enriched in cancerous tissues.	antral gastric biopsies	[73]
47 patients including SG, AG, gastric intraepithelial neoplasia (GIN), and GC.	Oral bacteria such as Slackia, Selenomonas, Bergeyella and Capnocytophaga were enriched in cancerous tissues.	gastric mucosal specimens	[65]