This is a non-therapeutic study. Pediatric AML patients undergoing HCT with a myeloablative preparative regimen may be enrolled. Subjects can be enrolled 10-40 days prior to HCT. Three samples for MRD (measured by WT1 PCR and flow cytometry) will be collected from peripheral blood and bone marrow: 1) pre-HCT (<3 weeks prior to starting the preparative regimen), 2) day 42 +/- 14 days post HCT (early post-engraftment), and 3) day 100 (+/-20 days) post HCT. For two years after transplant, the subject's follow-up data will be collected using the Research Level Forms in the CIBMTR Forms Net internet data entry system. The main objective is to determine whether there is any association between level of pre-transplant and post-transplant bone marrow MRD using WT1 and flow cytometry with 2-year event-free-survival, and to estimate the strength of that association in terms of the predictive accuracy of MRD. The investigators hypothesize that measurable MRD at either time point will be associated with decreased 2-year event-free survival.