Escherichia coli (AIEC) NC101 is a mouse isolate, serotype O2:H6/41, that is pro-carcinogenic, adherent-invasive (AIEC), probiotic strain of Escherichia coli, a species of bacteria that thrives in the intestines of mammals.[1][2] NC101 has also been identified as a nicotinic acid (NA) auxotroph, a pathobiont, which is an organism that is harmful under certain circumstances,[3] and is an important, relevant model organism that demonstrates how susceptible individuals may produce inappropriate immune responses to seemingly benign intestinal E. coli.[4]
E. coli NC101 has been found to promote carcinoma specifically, mucinous adenocarcinoma, in while performing experiments in azoxymethane treated mice. The findings of the study found "...tumorigenesis by altering microbial composition and inducing the expansion of microorganisms with genotoxic capabilities."[6] The frequency of specific E. coli strains like NC101 in laboratory mouse colonies is currently unknown.[citation needed]