JAK3 and precursor B-cell acute lymphoblastic leukemia: Additionally, one JAK3 mutation A572V was identified in acute megakaryoblastic leukemia.628 Among these mutations, several others were detected in the JAK3 protein: P132T,628 Q501H + R657Q,629 A573V,630 M576L,631 A593T631 and V722I617 in acute megakaryoblastic leukemia, while S789P609 was detected in childhood B-ALL.