AKT1 and neoplasm: PTEN was normally expressed in both, with a sub-cellular distribution similar to the corresponding normal breast tissue; conversely, p-AKT (Ser473) staining showed a markedly increased AKT phosphorylation in the tumors, compared to the normal tissue (Figure 2D), suggesting that the PI3K/Akt/mTOR pathway is over-activated in the tumor, unlike in normal tissue.