RUNX1-FPD primary bone marrow MNCs treated with inhibitors of RUNX1 proteolytic degradation early during in vitro megakaryocyte differentiation. (A) Differentiation protocol. (B) Representative flow cytometric analysis of megakaryocytes generated from patient FPD-1 at the conclusion of the differentiation protocol. (C) Graphic representation of flow cytometric analysis, as depicted in panel B, relative to vehicle-treated control, for each patient (FPD-1, -2, and -3, or all 3 analyzed collectively). Immature megakaryocyte populations correspond to CD41a⁺/CD42b⁻ and mature populations correspond to CD41a⁺/CD42b⁺. Confidence interval represents standard deviation of 1 to 4 repetitions. (D) Cytocentrifuge preparation of cells (Wright-Giemsa stain) harvested at the conclusion of the differentiation protocol. Representative results obtained from FPD-2. Arrowheads indicate blebs consistent with proplatelet formation. (E) Myosin and RUNX1 expression after drug treatment in primary bone marrow samples. qRT-PCR for the indicated genes at day 14 of differentiation of primary bone marrow cells (FPD-2; n = 2). *P < .05, using a 2-tailed Student t test assuming unequal variance.