FAB (French-American-British) classification

This system was created by a group of scientists from France, the United States, and the UK in order to classify leukemia according to the type of cell from which the cancer originated and the degree of maturity of the cell at that moment. In this classification we can find 9 different subtypes, spanning M0 to M7.


M0 Undifferentiated acute myeloblastic leukemia.

M1 Acute myeloblastic leukemia with minimal maturation.

M2 Acute myeloblastic leukemia with maturation.

M3 Acute promyelocytic leukemia (APL).

M4 Acute myelomonocytic leukemia.

M4 eos Acute myelomonocytic leukemia with eosinophilia.

M5 Acute monocytic leukemia.

M6 Acute erythroid leukemia.

M7 Acute megakaryoblastic leukemia.


Subtypes M0 to M5 start in immature forms of white blood cells. M6 AML starts in very immature forms of red blood cells, while M7 AML starts in immature forms of platelets.


WHO classification

EThe FAB classification system is still used to group AML into subtypes, though it doesn't take into account factors known to affect prognosis. For this reason, the WHO has developed a system that includes some of these factors, thereby dividing AML into several groups:


  • AML with genetic abnormalities:

AML with a translocation between chromosomes 8 and 21; t(8; 21) (q22;q22)

AML with inversion (16) (p13q22) or translocation (16; 16) (p13.1; q22)

AML with translocation (15; 17) (q22; q12)

AML with translocation (9; 11) (p22; q23)

AML with translocation (6; 9) (p22; q34)

AML with inversion (3) (q21q26.2) or translocation (3; 3) (q21; 26.6)

AML (megakaryoblastic) with translocation (1; 22) (p13; q13)


  • AML with myelodysplasia-related changes:

This group includes those patients previously diagnosed with a myeloproliferative or myelodysplastic syndrome.


  • AML not otherwise specified :

This includes cases of AML that don't fit into any of the aforementioned groups and is similar to the FAB classification


AML with minimal differentiation (M1)

AML with differentiation (M2)

Acute myelomonocytic leukemia (M4)

Acute monocytic leukemia (M5)

Acute erythroid leukemia (M6)

Acute megakaryoblastic leukemia (M7)

Acute basophilic leukemia

Acute panmyelosis with fibrosis


  • Sarcoma mieloide