These agents have been evaluated in the different subtypes of breast cancer (luminal, triple-negative, HER2+ tumors) thereby obtaining the greatest benefits when combined with standard therapies and in tumors presenting an hyperactivation of the PI3K signaling pathway (mostly due to PIK3CA activating mutations/amplification, inactivating mutations or loss of PTEN, or AKT activating mutations). The gene discussed is PIK3CA; the disease is breast carcinoma.