In vitro, GM-CSF treatment induced CD24 expression in mouse MPN senescent neutrophils; this was prevented by STAT5 (not STAT3) inhibitor (blocking signaling downstream of GM-CSF receptor)41, phenocopying the effect of ruxolitinib (Figure 3F; supplemental Figure 2L). This evidence concerns the gene CSF2 and myeloproliferative neoplasm.