RUNX1a overexpression in MDS, MDS/MPN, and AML patients with a history of MDS or MDS/MPN. (A-B) RUNX1 expression levels by quantitative reverse-transcription polymerase chain reaction in CD34⁺ cells from patients with MDS (A) or MDS/MPN (CMML and MDS/MPN-unclassifiable) (B). Relative RUNX1a and RUNX1b expression was calculated as a ratio relative to GAPDH expression; the ratio of RUNX1a to RUNX1b expression was also calculated. RNA from normal bone marrow CD34⁺ cells served as a control, their RNA level being defined as unity. *P < .05; **P < .01. Closed circles show RUNX1-mutated patients. BM, bone marrow. (C-D) Change in RUNX1 expression levels over time in a single patient with MDS (C) or MDS/MPN (D). Patient (Pt) 20, 42, 14, and 32 showed disease progression, whereas patient 302, who was treated with azacitidine (AZA), showed hematological improvement. The diagnosis was based on WHO2016.¹⁹  (E) Enforced RUNX1a expression in CD34⁺ cells from patients. Growth patterns of the GFP-sorted cells cultured on MS5 stromal cells are shown. EB, excess blasts; N.S., not significant; PB, peripheral blood.