Characterization of bone marrow mast cells in acute myeloid leukemia with t(8;21) (q22;q22); RUNX1-RUNX1T1

Mast cells are often increased in AML with t(8;21). We analyzed characteristics of mast cells to elucidate their relationship with leukemic blasts. In 31 cases in which the results of KIT mutation analysis were available, five cases showed mutations. None of the cases positive for KIT mutation showed increased mast cells. In five cases with increased mast cells in which targeted-FISH analysis was performed for RUNX1-RUNX1T1, fusion signals demonstrated the translocation in mast cells in all cases. These findings confirm the shared origin between mast cells and leukemic blasts in AML with t(8;21).