CD99 and acute myeloid leukemia: 1. CD99+CD49d+Galectin-1+CD52+ quiescent stem-like cells (QSCs) are involved in the chemoresistance and relapse of AML.2. Interaction between QSCs and monocytes mediated by CD52-SIGLEC10 leads to immune suppression and poor outcomes.3. LGALS1 is a promising target for refractory and relapsed AML.