After treatment with azoxymethane (AOM), a carcinogen that induces colon cancer,germ-free Il10−/− micemono-associated with the colitis-inducing E. coli NC101 straindeveloped invasive mucinous carcinomas, while mice mono-associated withEnterococcus faecalis, another colitis-inducing bacterial strain,did not. The gene discussed is IL10; the disease is colitis.