The myocardin-related transcription factor megakaryoblastic leukemia (MKL) induces the expression of the signal transducer and activator of transcription 1 (STAT1) via its SAP-domain (SAF-A/B, acinus and PIAS protein domain) activity, which upregulates PFN expression [47]. Here, STAT1 is linked to adult acute megakaryoblastic leukemia.