In recent years, the therapeutic landscape for HR + breast cancer has unprecedentedly evolved by the introduction of cyclin-dependent kinase 4 and 6 inhibitors (CDK4/6i) (Goyal et al., 2023), which can improve the prognosis by combating resistance to traditional ET alone and emerged as a cornerstone in the treatment of advanced or metastatic disease (Morrison et al., 2024). The gene discussed is CDK4; the disease is metastatic neoplasm.