Since Akt1 and Akt2 have been implicated in epithelial to mesenchymal transition in some mammary models [30,35,36], immunohistochemical analysis of cytokeratins 5, 8, 14 and 18 was performed to determine whether the type of mammary tumors that developed in MTB-IGFIR/Akt1−/− or MTB-IGFIR/Akt2−/− mice differed from the tumors that developed in MTB-IGFIR mice. This evidence concerns the gene AKT1 and breast cancer.