AML-962: Prognostic Impact of CD34+CD38− Leukemic Stem Cell Frequency in Pediatric Patients With Acute Myeloid Leukemia

Leukemia stem cells (LSCs) are implicated in the persistence and relapse of acute myeloid leukemia (AML), particularly in pediatric patients. In this study we aim to assess LSC frequency among pediatric patients with AML and its correlation with clinical outcomes. It is a retrospective cohort study including all patients ≤18 years old with de novo AML who were treated at Children's Cancer Hospital Egypt 57357.We collected leukemic stem cell markers (CD34 + CD38 low/– ) using multi-parametric flow cytometry (MFC). The study included 383 pediatric patients with newly diagnosed AML treated at Children's Cancer Hospital Egypt 57357. LSC markers (CD34 + CD38 low/– ) were assessed using MFC. LSCs were present in 22% of the cohort at diagnosis, with higher prevalence in French American British subtypes M2 and M4 ( P = 0.007). Significant association was observed between LSC frequency and CD123 expression ( P < 0.001), but not with gender, initial leukocyte count, and cytogenetics ( P = 0.6, P = 0.7, P = 0.8, respectively). Although LSC positivity correlated with higher measurable residual disease levels post-induction (≥0.1%), the association was not statistically significant ( P = 0.13). Three-year overall survival was lower in LSC-positive patients (45.2%) compared to LSC-negative patients (49.8%) but without significance ( P = 0.4). Relapse was more frequent among LSC-positive patients (46%) compared to LSC-negative patients (37%), though the difference was not statistically significant ( P = 0.3). These findings emphasize the prognostic significance of LSC frequency and CD123 expression in pediatric AML, suggesting that targeted therapeutic interventions could improve patient outcomes.