After the discovery of an epidemiological association between
E. coli-associated chronic inflammation and CRC, several mechanisms
have been indicated in E. coli that possibly contribute to tumor
development. Recently, when germ free IL-10 −
/
− mice were colonized
with E. coli, it was found that E. coli increased the development
of colitis and colon cancer. This study further indicated that the
polyketide synthase (pks) pathogenicity island enhances the ability
of E. coli to cause colon cancer. Removal of pks from E. coli
resulted in less DNA damage and neoplastic lesions in colonized
IL-10 −
/
− mice [5]. pks pathogenecity island genes code for multienzyme
machinery that is responsible for synthesis of several
important metabolites, including colibactin. Colibactin increases the
oncogenic potential of cells through its ability to induce senescence
[6]. Nevertheless, this association is still lacking a complete
framework on how E. coli intracellular infection can influence progression
of inflammatory diseases into colon cancer.