PTEN and breast cancer: Since preclinical evidences suggest that alterations in the PI3K/AKT pathway may confer sensitivity to AKT inhibition in BC models (Davies et al., 2012; Sangai et al., 2012; Lin et al., 2013), PIK3CA, AKT, and PTEN mutations along with PTEN expression levels have been extensively investigated in clinical trials testing AKT inhibitors.