PIK3CA and breast cancer: The PI3K-AKT-mTOR pathway inhibitors in TNBC, CDK 4/6 inhibitors in HR+ HER2− breast cancer, and monoclonal antibodies against HER-2 alone or associated with chemotherapy or a drug in HER2+ breast cancer are examples of the former, and PARP inhibitors again in TNBC are an example of the latter modality.