RAB27B and chronic myelomonocytic leukemia: Consistent with our Q61R results, mice transplanted with Rab27bfl/fl LSKs expressing NRASG12D mostly developed MML, while those transplanted with Rab27b-deficient LSKs expressing NRASG12D had reduced incidence of CMML and instead died of T-ALL (Table 2), as evidenced by flow cytometric analysis (Figure 6B) and the histology of the bone marrow and spleen (Figure 6C and Supplemental Figure 8B).