Genetic mutations, such as those in PIK3CA, play a critical role in breast cancer progression, pathological classification, and prognosis.12, 13, 14 PIK3CA, located on chromosome 3, encodes the p110α catalytic subunit of PI3K and is frequently mutated in breast cancer, particularly in HR+/HER2- subtypes.15 The gene discussed is ERBB2; the disease is breast carcinoma.