Acute Myeloid Leukemia and Markers of Leukemia Stem Cells (CLL1 and CD45RA)

Concordance between the relative fraction of Leukemia Stem Cells (LSC) vs Hematopoietic Stem Cells (HSC) and treatment response

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. The research we are proposing here is to investigate 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. Our retrospective study have
 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 us 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.