KRAS and infectious otitis media: In the AOM mouse model, MAM-induced mutation of K-ras (i.e., transversion from G:C to A:T at codon 12 derived from O6-mG lesions) activates this pathway and the downstream MAPK and Phosphoinositide 3-kinase/Akt (PI3K/Akt) mediators, indicating that MAM perturbs gene expression in these pathways by a DNA damage-dependent mechanism.