Role of gut microbiome in regulating the effectiveness of metformin in reducing colorectal cancer in type 2 diabetes

Table 2 Summary of the alteration of gut microbiota in patients with type 2 diabetes mellitus and the common alteration with both type 2 diabetes mellitus and colorectal cancer from 2012 to 2019

Status	Classification	T2DM	T2DM and CRC
Increased1	Phyla	Verrucomicrobia, Proteobacteria, Actinobacteria, Euryarchaeota, Firmicutes	Firmicutes
	Order	Lactobacillales, Bacteroidales
	Families	Lachnospiraceae, Erysipelotrichaceae	Lachnospiraceae, Erysipelotrichaceae
	Genera	Ruminococcus, Enterobacteriaceae, Eggerthella, Desulfovibrio, Escherichia, Haemophilus, Clostridium, Eubacterium, Subdoligranulum, Bacteroides, Parabacteroides, Bifidobacterium spp., Lactobacillus	Enterobacteriaceae, Desulfovibrio, Escherichia, Clostridium, Eubacterium, Bacteroides, Parabacteroides, Bifidobacterium spp.Species: Alistipes,
	Species	Akkermansia, Alistipes, Parabacteroides
Decreased1	Phyla	Tenericutes, Fusobacteria, Firmicutes, Bacteroidetes, Verrucomicrobia, Proteobacteria, Elusimicrobia
	Families	Lachnospiraceae, Peptostreptococcaceae, Flavobacteriaceae, Clostridiaceae	Lachnospiraceae, Clostridiaceae
	Genera	Bacteroides, Anaerostipes, Roseburia, Faecalibacterium, Bifidobacterium	Bacteroides, Bifidobacterium
	Species	A. muciniphila, F. prausnitzii

¹Compared with healthy volunteers. A simultaneous increase or decrease of a certain bacteria means that the current research on this bacteria is still controversial. CRC: Colorectal cancer; T2DM: Type 2 diabetes mellitus.