In the phase III CLEOPATRA study, patients with HER2 + advanced breast cancer and the PIK3CA activating mutations had a worse prognosis versus patients with HER2 +/PIK3CA wild-type tumors, regardless of the anti-HER2 treatment administered (trastuzumab or trastuzumab + pertuzumab) (6). This evidence concerns the gene ERBB2 and breast carcinoma.