Translocation t(8;21) is found in 5-12% of AML. Among the non-random chromosomal aberrations observed in AML, t(8;21)(q22;q22) is one of the best known and usually correlates with AML M2, with well defined and specific morphological features. The common morphological features include the presence of large blast cells with abundant basophilic cytoplasm, often containing numerous azurophilic granulations; few blasts in some cases show very large granules (pseudo-Chediak-Higashi granules), suggesting abnormal fusion. Auer rods are frequently found. In addition to the large blast cells, there are also some smaller blasts, predominantly found in the peripheral blood. Promyelocytes, myelocytes and mature granulocytes with variable dysplasia are seen in the bone marrow. These cells may show abnormal nuclear segmentation and/or cytoplasmic staining defects including homogeneous pink colored cytoplasm - Text and iconography Courtesy Georges Flandrin 2001.

t(8;21)(q22;q22) : cohybridization experiments using dJ155L8 (RUNX1T1) and dJ1107L6 (RUNX1 ); note the splitting of RUNX1 and colocalization on der(8) with RUNX1T1 - Courtesy Mariano Rocchi, Resources for Molecular Cytogenetics.

RUNX1 and RUNX1T1 breakpoints in the t(8;21) / 5 RUNX1 - 3 RUNX1T1 fusion gene, and FISH - Courtesy Hossein Mossafa.

t(8;21)(q22;q22) G- banding (left) - Courtesy Jean-Luc Lai and Alain Vanderhaegen (top) and Diane H. Norback, Eric B. Johnson, Sara Morrison-Delap http://www.slh.wisc.edu/cytogenetics (middle and below); R- banding (middle) - above: Jean Loup Huret; 2nd row: - Courtesy Christiane Charrin; 3rd and 4th row: - Courtesy Roland Berger. Right: FISH - Courtesy Hossein Mossafa.