AML with t(6;9)(p23;q34)

Epidemiology and Etiology:

· Children and adults

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Common sites:

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Gross features:

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Histologic features:

• With or without monocytic features
• Basophilia (BM and PB) (44-62%) (uncommon in other AMLs)

· Multilineage dysplasia often

· nonspecific

· Any FAB subtype other than APL and megakaryoblastic

· Auer rods in 1/3

· Granulocytic and erythroid dysplasia (most)

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Immunophenotype:

Marker:

Sensitivity:

Specificity:

• nonspecific
• Positive: MPO, CD13, CD33, CD38, HLA-DR
• Most: CD117, CD34, CD15
• Subset: CD64, TdT
• Uncommon: other lymphoid markers
• Variable: NSE

Molecular features:

· DEK on chromosome 6

· NUP214 (CAN) on chr 9

· Nucleoporin fusion protein acts as an aberrant transcription factor

· Associated karyotypic changes:

· None in the bast majority

· Complex karyotype in some

· FLT3-ITD mutations very common (69% in kids, 78% in adults)

· FLT3-TKD mutations uncommon

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Other features:

· WBC count generally lower than other AML types in adults

· Unfavorable prognosis in both kids and adults

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References:

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