This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Pharmacology
Trastuzumab all are true EXCEPT - 
Select and explain. 
A. Shows better response in combination with paclitaxel, B. Used in metastatic breast cancer, C. Causes upregulation of HER2/neu, D. Do not causes bone marrow toxicity
C: Causes upregulation of HER2/neu
Answer: C: Causes upregulation of HER2/neu 
Explanation: Ans. is 'c' i.e., Causes upregulation of HER2/neu o It has been suggested that trastuzumab induce some of its effects by down regulation of HER2/neu (not upregulation) o Currently transtuzumab is approved for HER2/neu overexpressing metastatic breast cancer in combination with paclitaxel as initial treatment or as monotherapy following chemotherapy. o Herceptin use is associated with infusion-related hypotension, flushing and bronchoconstriction, and skin rash but no bone marrow toxicity.