This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Other topics and Adverse effects, Subject name: Anatomy
Which of the following drugs is used as an immunosuppressive but lacks anticancer activity 
Select and explain. 
A. Methotrexate, B. 6-mercaptopurine, C. Azathioprine, D. 5-flurouracil
C: Azathioprine
Answer: C: Azathioprine 
Explanation: Ref-KDT 6/e p819,820,838 Azathioprine is an an antimetabolite that is used as an immunosuppressant but not as an antineoplastic drug. It is a product and this conveed to its active metabolite in the Lymphoid Cells only