Marker patterns in typical acute myeloid leukaemia
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CD45 expression in AML
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CD45 expression in AML is "weak" i.e. significantly less intense than normal T cells, B cells or monocytes. The typically low side scatter of most blast cells means that myeloid blast cells tend to form a relatively uniform population that is clearly separated from that of lymphocytes on CD45/SSc plots. However, there is some variability releted to indididual subtypes - in AML see particularly our sections on APL and monocytic AML.
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Markers of pimitive cell type expected in AML
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These markers are generally regarded as indicating less differentiated cells, so may be expressed by any acute leukaemia type. When strongly expressed they have some value in indicating T or B lineage.
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Marker
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Expectation
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Comment
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CD34
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Frequently expressed, most often in less differentiated forms of AML. Expression often less intense than in lymphoid leukaemias
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TDT
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Expressed particularly in less differentiated forms of AML. Often on a sub-population of cells; expression usually less intense than in lymphoid leukaemias
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CD7
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Similar to TdT, CD7 expression is recognised on a proportion of AML, usually those with less differentiated phenotype. Most consistently expressed in T-ALL.
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Markers with very strong lineage specificity in AML
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While not expressed by all cases, when detected by flow cytomwtry MPO can be considered to be lineage-defining marker in AML (or establishing myeloid lineage in MPAL).
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Marker
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Expectation
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Comment
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MPO
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A strong lineage marker for AML when detected by flow cytometry (though potentially less so by immunocytochemistry)
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Lineage markers in AML that with relatively high speificity
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These markers are each expressed by many cases (around 80% for each marker), they have high specificity although abberrent expression in ALL is feequent (overall 10-20% for any individual marker)).
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Marker
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Expectation
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Comment
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CD117
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One of tne of the first lineage-markers acquired in AML with good relative specificity
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CD33
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A good marker for AML that is often less strongly expressed in monocytic forms
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CD13
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A good lineage marker for AML aquired a little later, higher than CD13 in monocytic forms
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Other markers helpful in detecting myeloid lineage (often in AML subtypes)
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These markers have less general value in diagnosis, but can be useful in subtype selection or in cases whwere lineage is ambiguous.
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Marker
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Expectation
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Comment
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CD10
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Gran
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One of tne of the first lineage-markers acquired in AML with good relative specificity
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CD11b
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Gran
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One of tne of the first lineage-markers acquired in AML with good relative specificity
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CD11c
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Mono
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One of tne of the first lineage-markers acquired in AML with good relative specificity
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CD14
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Mono
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A good marker for AML that is often less strongly expressed in monocytic forms
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CD64
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Mono
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A good lineage marker for AML aquired a little later, higher than CD13 in monocytic forms
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