<prompt> Non-specific esterase is positive in all the categories of AML except -M3M4M5M6  <response>: Nonspecific esterase NSE is characteristic of M4 Acute myelomonocytic and M5 Acute monocytic leukemia only. NSE positivity is not a characteristic feature of other subclasses of AML. However, NSE positivity may also be seen in 15-20 of cases of M3 and in some cases of M7. NSE positivity is not a feature of M0, M1, M2 and M6 classes of AML. 