LSC frequency and heterogeneity increase after unsuccessful treatment of AML. In de novo AML, the LSC population is relatively uniform and present at a low frequency (LSC represented by green colored cell). Upon treatment with chemotherapy, when patients attain a remission and subsequently relapse, the relapse is characterized by increased numbers of LSCs and a more heterogeneous LSC population (indicated by green, orange, and yellow colored cells).¹⁰