While JAK2 bound to ruxolitinib should not be active, JAK2-dependent signaling proceeds during JAK2 inhibitor persistence, which is also evident in therapeutic mouse models of MPN—following an initial response to JAK2 inhibitor therapy, MPN phenotypes redevelop during JAK2 inhibitor monotherapy [49, 50]. The gene discussed is JAK2; the disease is myeloproliferative disorder.