ITGAM and acute myeloid leukemia: The absence of this clonal marker in the bulk leukemic population strongly suggests that the Mac1+/Gr1+ AML did not evolve from a Mac1−/Gr1− population with a clonal Tcrb DJ rearrangement but that the Mac1−/Gr1− clone with Tcrb DJ rearrangement was rapidly out-competed by a genetically distinct Mac1+/Gr1+ AML clone.