Clinical features of t(8;21) leukemia include: (1) association with acute myeloid leukemia (AML) M2 subtype in the FAB classification, characterized by granulocytic maturation in morphology, (2) positivity for the following immunophenotypic markers, HLA-DR+, CD117(c-KIT)+, CD34+, CD38+, CD13+, CD33+, CD19+, and CD56+, (3) chloroma, (4) predominant onset in adolescent and young adults (AYA), but not in aged population, (5) higher prevalence in Asia, and (6) requirement of additional genetic abnormalities such as mutations in c-KIT, FLT3, RAS, ASXL1, and ZBTB7A, -9q, or –Y [2, 3]. This evidence concerns the gene KIT and myeloid sarcoma.