AKT1 and breast cancer: Given that NEDD4 knockdown by both siRNAs resulted in the slow growth of BC (Fig. 1) and that there is no correlation between NEDD4 and PTEN protein expression in BC tissue samples (Fig. 5a), the results displayed in Fig. 5 suggest that NEDD4 promotes BC progression via the activation of IGF-1R/Akt signaling, perhaps independently of PTEN.