PDK1 and breast cancer: It is also important to underline that multiple abnormalities of the PI3K pathway all cooperate to induce the activation along the PI3K-AKT signaling root: in fact, the majority of breast cancers overexpress PDK1 (3-Phosphoinositide-dependent kinase 1), a serine threonine that is directly activated by PI3K and required for AKT activation [272].