The excessive activation of the PI3K/AKT/mTOR pathway is strongly linked to uncontrolled breast cancer development.57 Phosphatase and tensin homolog (PTEN) and inositol polyphosphate 4-phosphatase type II (INPP4B) are two crucial negative regulators of the PI3K pathway (Fig. 2). This evidence concerns the gene INPP4B and breast cancer.