Similarly, cluster C2, composed of 663 transcripts that exhibited high expression in AOM and ApcMin/+ tumors, but low in Smad3-/- and Tgfb1-/-; Rag2-/- tumors, included transcripts for contact growth inhibition (Metap1, Pcyox1), mitosis (Mif, Pik1), cell cycle progression and checkpoint control (Id2, Ptp4A2, Tp53). Here, TGFB1 is linked to infectious otitis media.