PROM1 and acute myeloid leukemia: Apart from this new insight into how to define residual disease, an advantage of the PM-MRD approach is that it circumvents most subjective elements of MRD identification, while less experience is required to define CD34+, CD117+, and CD133+ cells and aberrancies thereon than to define the extent to which normal bone marrow differentiation patterns have become aberrant in AML.