Prognostic value of frequencies of CD34⁺CD38⁻ putative LSC (pLSC) compartment at follow-up. The Kaplan-Meier analyses for RFS for the CD34⁺CD38⁻ pLSC compartment at follow-up for 3 consecutive therapy cycles are shown. The optimal cutoff levels were chosen to define high pLSC frequency (pLSC⁺) and low pLSC frequency (pLSC⁻) after first induction cycle (0.0003%, which is 3 pLSCs in 1 000 000 WBCs) and after second induction cycle and consolidation therapy (0.0001%, 1 pLSC in 1 000 000 WBCs). After the first induction cycle (A, 71 patients), second induction cycle (B, 77 patients), and after consolidation therapy (C, 48 patients), pLSC⁺ patients showed significantly poorer outcome as compared with pLSC⁻ patients.