Fig. 1.

Molecular basis of hematological malignancies; modified version of classical class I and class II theory. Combination of class I and II mutations induces leukemogenesis. Class I mutations including Bcr-Abl or JAK2 induce MPN including CML. With additional class II mutations, MPN undergoes leukemic change including blast crisis of CML (CML-BC). On the other hand, a class II mutation Runx 1 mutation induces MDS, which progresses to MDS/AML with additional class I mutations. Modified from Kitamura et al. (6).