IBD scores were not significantly different between DSS-treated Smad3−/− and Smad3/Rag-DKO mice (Figure 2a), although increased invasion scores, dysplasia scores and distribution of high grade dysplasia were seen in Smad3/Rag-DKO when compared to Smad3−/− (Figure 2A–D). Here, SMAD3 is linked to inflammatory bowel disease.