CDK4 and neoplasm: Treatment received varied depending on immunophenotype and clinical stage of the primary tumor; most patients (n=34; 69.4%) received hormone therapy and cyclin-dependent kinases 4 and 6 (CDK4/6) inhibitors if indicated, while 15 (30.6%) received chemotherapy-associated with anti-human epidermal growth factor receptor 2 (HER2) therapy or immunotherapy depending on the immunophenotype of the tumor.