Desmedt and colleagues identified alterations in one of three key genes of the PI3K pathway: PIK3CA, PTEN, and AKT1, in 50% of ILC breast cancer cases, each more frequently mutated in ER-positive/HER2-negative ILC breast cancer than in ER-positive/HER2-negative invasive ductal breast cancer tumours [16]. Here, PTEN is linked to breast cancer.