Leukemia - Acute
Recurrent genetic abnormalities
AML with t(8;21)(q22;q22) - RUNX1-RUNX1T1

Topic Completed: 1 December 2011

Revised: 17 January 2019, last major update December 2011

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PubMed Search: AML with t(8;21)(q22;q22) RUNX1 RUNX1T1

Syed Zaidi, M.D.
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Cite this page: Zaidi S. AML with t(8;21)(q22;q22) RUNX1-RUNX1T1 . PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/leukemiaAMLwitht821q22q22.html. Accessed September 23rd, 2019.
Definition / general
  • Translocation produces fusion product of RUNX1T1 (ETO) gene on #8q22 and RUNX1 gene on #21q22
  • ~ 5% of AML, and 10% of cases of AML-M2 (AML with maturation) in FAB classification
  • Most common type of childhood AML
  • RUNX1-RUNX1T1 may facilitate accumulation of genetic alterations by suppressing endogenous DNA repair (Blood 2008;111:2190)
  • Additional mutations are required for leukemogenesis (Proc Natl Acad Sci USA 2000;97:7521)
  • Frequently associated with additional chromosomal translocations which may influence prognosis (Zhonghua Nei Ke Za Zhi 2006;45:918)
  • Classify as AML even if initial blast count is < 20%
  • RT-PCR and cytogenetics for detection both have limitations (J Clin Oncol 2001;19:2482)
  • Variant t(8;21): similar clinical features, morphology and immunostaining as classic t(8;21) cases (Am J Clin Pathol 2006;125:267)
Prognostic factors
  • Favorable prognosis in adults, although KIT activating mutations confer poorer prognosis
  • Good response to chemotherapy and high complete remission rate
  • Expression of CD56 and KIT mutations are considered adverse prognostic factors
Case reports
Microscopic (histologic) description
  • Resembles AML-M2 (AML with maturation) - large blasts, abundant basophilic cytoplasm, frequent large Auer rods and chunky cytoplasmic granules, perinuclear hofs, neutrophil dysplasia
  • Trilineage dysplasia present in therapy related cases (Am J Clin Pathol 2002;117:306)
  • Peripheral blood contains smaller blasts
Microscopic (histologic) images

Images hosted on PathOut server:

Bone marrow smear (Wright-Giemsa):
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Myeloblasts with Auer
rods, promyelocytes
and other mature cells

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Myelocytes have abundant cytoplasm
with prominent granulation, one
myeloblast (slightly left and below
center) has prominent Auer rod

Images hosted on other servers:
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H&E and stains

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Large blast cells with abundant basophilic cytoplasm, often numerous
azurophilic granules, may have large granules (pseudo Chediak-
Higashi granules), often Auer rods, accompanied by promyelocytes,
myelocytes and mature granulocytes with variable dysplasia

Positive stains
Negative stains
Molecular / cytogenetics description
  • t(8;21)(q22;q22), RUNX1-RUNX1T1 AML1 gene also called RUNX1, encodes core binding factor alpha
Molecular / cytogenetics images

Images hosted on PathOut server:
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t(8;21) with abnormal
chromosomes on
right, and breakpoints
at arrowheads

Images hosted on other servers:
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Various images

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