French-American-British (FAB) Classification of AML

AB subtype Name % of adult AML patients Prognosis compared to average for AML
M0 Undifferentiated acute myeloblastic leukemia 5% Worse
M1 Acute myeloblastic leukemia with minimal maturation 15% Average
M2 Acute myeloblastic leukemia with maturation 25% Better
M3 Acute promyelocytic leukemia 10% Best
M4 Acute myelomonocytic leukemia 20% Average
M4 eos Acute myelomonocytic leukemia with eosinophilia 5% Better
M5 Acute monocytic leukemia 10% Average
M6 Acute erythroid leukemia 5% Worse
M7 Acute megakaryoblastic leukemia 5% Worse

Subtypes M0 through M5 all start in precursors of white blood cells. M6 AML starts in very early forms of red blood cells, while M7 AML starts in early forms of cells that make platelets.