This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Breast, Subject name: Surgery
[{'content': 'Recent drug for metastatic hormone receptor(+)and HER-2 (-) metastatic breast cancer : \nSelect and explain. \nA. Palbociclib, B. Ipataseib, C. Herceptin, D. Buparlisib', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Palbociclib is a recent drug for metastatic hormone receptor(+)and HER-2 (-) breast cancer. It works by inhibiting Cyclin-dependent kinase 4/6. Other examples of this class of drug includes: Ribociclib, Abemaciclib. These drugs are used along with letrozole (aromatase inhibitor) and/or fulvestrant (selective estrogen-receptor downregulator) Herceptin/Trastuzumabis used in Her-2 neu positive breast cancer. Ipataseib is an AKT (Protein kinase B) inhibitor used in metastatic triple-negative breast cancer. Buparlisib is a Phophatidyl-inositol 3 kinase (PI3k) inhibitor which is still in trial stages for treatment of metastatic breast carcinoma', 'role': 'assistant'}]