SMAD3 and cancer: For example, cluster C1, composed of transcripts that exhibited lower expression in Smad3-/- tumors and higher expression in AOM, ApcMin/+ and Tgfb1-/-; Rag2-/- tumors, contains 391 transcripts, including Cdk4, Ctnnb1, Myc, Ezh2, Mcm2 and Tcf3. Gene list over-representation analysis using Ingenuity Pathway Analysis applications demonstrated highly significant associations to cell cycle progression, replication, post-transcriptional control and cancer.