For de novo stage IV HR+ /HER2- breast cancers with PIK3CA mutation, inavolisib plus a CDK4/6 inhibitor and endocrine therapy is now the standard of care.21 We also observed relatively frequent PD-L1 amplification in TNBC, especially among de novo stage IV TNBC (4.6%). The gene discussed is CDK4; the disease is breast cancer.