rhIGFBP7 and ATRA combination treatment does not affect healthy NBM cells. NBM cells derived from healthy donors were incubated with PBS (Ctrl), 100 µg/mL rhIGFBP7, 0.5 µM ATRA, or the combination (Combi) for 5 to 7 days. The effects of the treatments were normalized against untreated control cells and plotted as mean ± SEM. NBM samples were analyzed for the percentage of viable cells (A), CD45^dim cells (B), myeloid CD45^dimCD33⁺ cells (C), CD45^dimCD34⁺ cells (D), CD3⁺ T cells (E), and CD19⁺ B cells (F) using flow cytometry and quantified relative to flow count beads. (G) CFU progenitor assays of NBM samples (in duplicate) after 7 days of treatment.