For example, while ApcMin/+ and AOM tumors are characterized by cytologic atypia (that is, nuclear crowding, hyperchromasia, increased nucleus-to-cytoplasm ratios and minimal inflammation), tumors from Smad3-/- and Tgfb1-/-; Rag2-/- mice show less overt dysplastic changes but exhibit a significant inflammatory component. Here, SMAD3 is linked to infectious otitis media.