SMAD3 and dysplasia: However, low grade dysplasia developed in the distal colon of 1/6 and 2/12 3%-DSS-treated Smad3+/− and WT mice, respectively, at the 17-week end point and 1/15 DSS-cycles treated Smad3+/− developed high grade dysplasia (grade 3) in the cecum (Figure S2B).