Breast cancer (BC) is the most common malignancy among women, accounting for 253,000 new cases in the United States in 2017.[1] Despite advances in screening and treatment, 50% of BC cases relapse.[2] Research efforts have not yet established targetable alterations with clinical value, with the exception of hormone receptors (HR) and I cERBB2 i .[3],[4] Recently, next-generation sequencing (NGS) techniques have given deeper insight into the genomic landscape of BC. There has been a paradigm shift to a model in which the choice of therapy reflects genetic alterations in the tumor of an individual patient. DISCUSSION Herein, we document a rare case of remarkable and rapid response to the PI3K inhibitor copanlisib in a heavily pretreated patient with BC and I PIK3CA i mutation after chemotherapy and hormonal therapy (HT) failure. In addition, six of eight patients remaining on treatment 12 months or longer had I PIK3CA i mutations.[22] In conclusion, our patient serves as a paradigm of NGS-driven treatment. [Extracted from the article]