PIK3CA and breast cancer: The targeted therapeutics approved for breast cancer include multiple agents targeting HER2 (commonly referred to as human epidermal growth factor receptor 2) amplification (trastuzumab16, pertuzumab17, ado-trastuzumab emtansine18, lapatinib19, and neratinib)20, and PARP inhibitors (olaparib21 and talazoparib)22 for BRCA1/2-mutated advanced breast cancers and PI3K inhibitors (alpelisib)23 for PIK3CA-mutated advanced breast cancers.