JAK1 and leukemia: Importantly, leukemia cell viability relied on maintenance of high IL-7R-mediated signaling, as shown by inhibition of JAK1, STAT5, or PI3K/mTOR signaling (Fig. 4h), or by the use of the bromodomain inhibitor JQ1 to concomitantly target IL7R and MYC transcriptionally32 (Supplementary Fig. 15).