In the literature: February 2022.

PIK3CA is one of the most frequently mutated oncogene in cancer. Phosphoinositide 3-kinase (PI3K) is a heterodimer comprising two subunits: a catalytic subunit (p110) and a regulatory subunit (p85). Activating mutations in PIK3CA are found in ∼30%-40% of patients with breast cancer (BC) and induce hyperactivation of the catalytic subunit.1 This mutation has been associated with endocrine therapy resistance in luminal BC, and also with anti-HER2 therapy in HER2+ BC. In May 2019, alpelisib, an α-specific PI3K inhibitor, was approved for the treatment of patients with advanced PIK3CA-mutant luminal BC.