B-Cell Acute Lymphoblastic Leukemia/Lymphoma (B-ALL) accounts for ~80-85% of ALL cases. 75% occur in children < 6 years of age. The remainder of ALL cases are of T-cell origin. T-ALL more commonly presents as extra nodal disease.
Immunohistochemical Profile
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Stain
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Comment
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Positive
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Positive. Up to 10% of T-ALL cases may be positive.
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Positive in most cases. CD10 negative cases may be associated with MLL gene rearrangements.
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Variably positive.
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CD22
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Positive (cytoplasmic)
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Variably positive. t(12;21) and hyperploidy cases are often CD34+.
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+/-
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Positive. Approximately 95% sensitive.
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CD13
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+/- Myeloid markers do not exclude the possibility of an ALL.
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+/- Myeloid markers do not exclude the possibility of an ALL.
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MPO
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Negative. Positivity would support either an AML or a B/myeloid leukemia.
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Typically Negative
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Expression is associated with t(9;22) in adults.
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Positive (nuclear expression). Sensitive and specific marker of B-cell lineage, but a subset of AMLs may express PAX-5 [t(8;21)].
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MPO – myeloperoxidase
References
Hematopathology. [edited by] Jaffe, ES. 1st. ed. Elsevier, Inc. © 2011.