JAK2 and hematologic disorder: As two representative Type-II JAK2 inhibitors, BBT594 and CHZ868 (Fig. 1B) show good potency and selectivity toward JAK2 (BBT594: IC50 = 0.99; CHZ868: IC50 = 0.11 uM, Table 1), and are also effective towards several hematological malignancies that are always refractory to Type-I JAK2 drugs22–26.