JAK2 inhibitor persistence in MPN was originally described by Koppikar et al. [41] who demonstrated that MPN model cells could be made to grow in high concentrations of ruxolitinib (and other type 1 JAK2 kinase inhibitors) and that this drug resistant state was reversible—cells cultured after removing the drug regain their sensitivity to JAK2 inhibitors. This evidence concerns the gene SGCG and myeloproliferative disorder.