AOM/DSS treatment induces increased frequency of colonic adenocarcinomas in Myd88^−/− mice. Cohorts of 15 Myd88^−/− mice and 20 WT mice were injected i.v. with AOM on day 0 followed by a single DSS cycle. Animals were monitored during 6 mo after treatment for survival (P = 0.0005, WT vs. Myd88^−/−; A). All the colons were analyzed for polyps when mice reached any of the end points for euthanasia or at the completion of the experiment (***, P < 0.001; B). Colon sections were fixed and stained with hematoxylin-eosin. 17 polyps from the WT group and 52 polyps from Myd88^−/− knockout mice were analyzed histologically. Photomicrographs of representative sections from the respective groups are shown at 20× (C). The percentage of mice developing adenocarcinomas is indicated (D). Photomicrographs of representative adenocarcinomas from multiple of those that developed in Myd88^−/− mice are shown at 40× magnification (E–G). The data shown in this figure were obtained from a single experiment performed treating the mice with one DSS cycle but closely mimic the data obtained from two other independent experiments with mice treated with two DSS cycles that are shown in Fig. S1.