This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Miscellaneous, Subject name: Medicine
. Tretinoin is useful in the treatment of - 
Select and explain. 
A. M2, B. M3, C. M5, D. M7
B: M3
Answer: B: M3 
Explanation: Tretinoin is a cancer medication used to treat acute promyelocytic leukemia Acute Promyelocytic Leukemia For use in patients with APL classification M3, which is characterized by the presence of t(15;17) translocation and/or the presence of the PML/RAR-alpha gene, who are refractory to, or have relapsed from, anthracycline chemotherapy, as well as for use in patients for whom anthracycline-based chemotherapy is contraindicated Ref Davidson 23rd edition pg 1313