Acute myeloid leukemia (AML) is a malignant disorder of the bone marrow and the most common form of acute leukemia in adults. Patient with AML have the shortest survival compared to other forms of leukemia. In the past 6 years, several new therapies have been approved. Biomarkers are in urgent need to guide therapeutic regimen selection in order to maximize the benefit of available therapies and minimize treatment toxicity. Current standard practice is to perform bone marrow biopsy at end of treatment cycle (each cycle around 28 days), and based on bone marrow finding, to decide further treatment plan. It is invasive and time consuming. In this study investigators will study whether tracking leukemia stem cells (LSC) in peripheral blood during early treatment cycle may provide a non-invasive method to predict therapeutic outcome at end of treatment cycle. A retrospective study found that LSC fractional change, defined by two LSC markers, named CLL1 and CD45RA, is highly correlated with therapeutic outcome. Further more, CLL1 and CD45RA positive LSC fraction demonstrates a high concordance between bone marrow and peripheral blood, offering the opportunity to track CLL1 and CD45RA positive LSC fraction non-invasively in peripheral blood during treatment. This pilot study will allow the investigators to decide whether testing CLL1 and CD45RA positive LSC in peripheral blood during leukemia treatment is feasible in clinical practice. This result will lay the foundation for designing future trials using CLL1 and CD45RA positive LSC fractional change to optimize therapeutic strategy for patients with AML.