Bacteria, inflammation, and colon cancer

Table 1 Effect of colonic bacterial flora on the development of gastrointestinal cancers in genetically-engineered mice

Gene	Function	Incidence of carcinoma (%)
		Conventional	Germ-free
TCRβ/p53[3]	Cellular immunity/ growth and division	70	0
IL-10[4]	Anti-inflammation	7	0
Gpx1/Gpx2[5]	Peroxidative stress	25	0
Gαi2[7]	Cellular signaling	31	ND
Smad3[8]	Tgfβ signaling	100	ND
Muc2[9]	Major component of the mucus	69	ND
Tgfβ1/Rag2[10,11]	Anti-inflammation/antigen receptor rearrangement	100	ND
IL-2/β2m[12]	Proinflammation	32	ND

ND: Not determined.

Table 2 Effect of colonic bacterial flora on the development of intestinal inflammation in genetically-engineered rodents

Gene	Function	Type of inflammation
		Conventional	Germ-free
IL-10[13,14]	Anti-inflammation	Neutrophilic, severe, death	Negative
IL-2[16]	Proinflammation	Lymphocytic, severe, death	Mild, focal
HLA-B27/β2m[17]	Human leukocyte antigen/MHC β chain	Lymphocytic, severe	Negative
TCRα[18]	T cell receptor α chain	Lymphocytic	Negative
Gαi2[7]	Cellular signaling	Lymphocytic, plasmacytic	ND
Tgfβ1/Rag2[11]	Anti-inflammation/antigen receptor rearrangement	Granulocytic	ND
mdr1a[19]	ABC transporter	Lymphocytic, granulocytic	ND
K8[20]	Major intermediate filament protein	Lymphocytic	ND
Smad3[21]	Tgfβ signaling	Lymphocytic	ND

ND: Not determined.