There are at least 10 different JAK inhibitors undergoing various phases of clinical trials [11] including a group of TKIs used for both MPDs and non-MPDs, namely MK-0457 (previously VX-680), that has had JAK2 inhibitory action in MPD and reduced kinase activity in T315I-positive ALL and CML [2]. The gene discussed is JAK2; the disease is acute lymphoblastic leukemia.