ERBB2 and aneurysmal bone cyst: In the epoch‐making CLEOPATRA trial, patients with HER2‐positive ABC who had not received prior trastuzumab achieved an unprecedented improvement in OS with docetaxel plus trastuzumab and pertuzumab, which established the dual HER2 blockade by trastuzumab and pertuzumab as first‐line treatment for HER2‐positive ABC.