Classification of acute myeloid leukemia

Last medical review:

The classification system for acute myeloid leukemia (AML) was developed by the World Health Organization (WHO). An older system called FAB classification (based mainly on how the leukemia cells look under a microscope) is no longer in use.

WHO classification system

The WHO system uses cell characteristics and genetics to classify AML into several groups.

AML with certain genetic abnormalities

Some types of AML have specific gene or chromosome changes:

  • AML with a translocation between chromosomes 8 and 21, RUNX1-RUNX1T1

  • AML with a translocation or inversion in chromosome 16, CBFB-MYH11
  • APL with the PML-RARA fusion gene (translocation between the PML region in chromosome 15 and the RARA gene region in chromosome 17)
  • AML with a translocation between chromosomes 9 and 11, MLLT3-KMT2A
  • AML with a translocation or inversion in chromosome 3, GATA2, MECOM
  • AML (megakaryoblastic) with a translocation between chromosomes 1 and 22, RBM15-MKL1
  • AML with the BCR-ABL1 (BCR-ABL) fusion gene
  • AML with mutated NPM1 gene
  • AML with biallelic mutations of the CEBPA gene (mutations in both copies of the CEBPA gene)
  • AML with mutated RUNX1 gene

AML with myelodysplasia-related changes

Some types of AML can develop after myelodysplastic syndromes or myelodysplastic/myeloproliferative neoplasms.

AML related to previous chemotherapy or radiation

This type of AML is related to previously having had chemotherapy with an alkylating drug or radiation therapy.

AML, not otherwise specified

This is used for AML that does not fall into one of the other categories. This classification is based on how the leukemia cells look under a microscope and includes:

  • AML with minimal differentiation

  • AML without maturation

  • AML with maturation

  • acute myelomonocytic leukemia (AMML)

  • acute monocytic leukemia

  • pure erythroid leukemia

  • acute megakaryoblastic leukemia

  • acute basophilic leukemia

  • acute panmyelosis with myelofibrosis

Myeloid sarcoma

Myeloid sarcoma is a tumour that occurs outside of the bone marrow.

Myeloid proliferations related to Down syndrome

This is AML related to Down syndrome.

Undifferentiated and biphenotypic acute leukemias

These leukemias have both lymphoblastic and myeloid features. They are very rare. They are sometimes called mixed phenotype acute leukemias.

Expert review and references

  • John Storring, MD, CM
  • Robert Turner, MD, FRCPC
  • Seiter K. Medscape Reference: Acute Myeloid Leukemia (AML) . WebMD LLC; 2021:
  • Leukemia and Lymphoma Society. The AML Guide: Information for Patients and Caregivers. Rye Brook, NY: 2019:
  • American Cancer Society. Acute Myeloid Leukemia Early Detection, Diagnosis, and Types . 2018:
  • PDQ® Adult Treatment Editorial Board. Acute Myeloid Leukemia Treatment (PDQ®) – Health Professional Version. Bethesda, MD: National Cancer Institute; 2021:
  • National Comprehensive Cancer Network. NCCN Guidelines for Patients: Acute Myeloid Leukemia. 2020.

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