Acute leukaemia types: Difference between revisions
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</br>When present on blast cells|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).</br> | </br>When present on blast cells|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).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)).</br> | ||
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|colspan="1" style = "font-size:90%; color:black;" |'''[[MPO]]''' | |colspan="1" style = "font-size:90%; color:black;" |'''[[MPO]]''' | ||
|colspan="1" style = "font-size:84%;"|A strong lineage marker for AML when detected by flow cytometry (though potentially less so by immunocytochemistry) | |colspan="1" style = "font-size:84%;"|A strong lineage marker for AML when detected by flow cytometry (though potentially less so by immunocytochemistry) | ||
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|colspan="1" style = "font-size:90%; color:black;" |'''[[CD117]]''' | |colspan="1" style = "font-size:90%; color:black;" |'''[[CD117]]''' | ||
|colspan="1" style = "font-size:84%;"|One of tne of the first lineage-markers acquired in AML with good relative specificity | |colspan="1" style = "font-size:84%;"|One of tne of the first lineage-markers acquired in AML with good relative specificity | ||
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|colspan="1" style = "font-size:90%; color:black;" |'''[[CD33]]''' | |colspan="1" style = "font-size:90%; color:black;" |'''[[CD33]]''' | ||
|colspan="1" style = "font-size:84%;"|A good marker for AML that is often less strongly expressed in monocytic forms | |colspan="1" style = "font-size:84%;"|A good marker for AML that is often less strongly expressed in monocytic forms | ||
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|colspan="1" style = "font-size:90%; color:black;" |'''[[CD13]]''' | |colspan="1" style = "font-size:90%; color:black;" |'''[[CD13]]''' | ||
|colspan="1" style = "font-size:84%;"|A good lineage marker for AML aquired a little later, higher than CD13 in monocytic forms | |colspan="1" style = "font-size:84%;"|A good lineage marker for AML aquired a little later, higher than CD13 in monocytic forms | ||
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Revision as of 17:57, 19 July 2023
Marker expression guide: acute myeloid leukaemia | |||
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Markers with value in confirming primitive phenotype (expressed in both AML and ALL)
(1) The typically low CD45 expression and 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 and is used to identify them in "gating" (please see CD45). Also be aware of AML forms that have do not fit these typical patterns particularly APL and monocytic AML (2) Other markers such as CD34, TdT and CD7 are expressed by "primitive cells" and can help increase diagnostic confidence that blast cells are present - although their presence is not required if other features fit. (3) While not fully specific for any given lineage, in some cases particular primitive markers are more frequently associated with particular lineages so may contribute to lineage assignment in difficult cases (see comments).
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Strong role in establishing the primitive nature of AML | |||
CD45 | Expressed by all leukocytes and precursors (100% of cases), but in AML expression is "weak" i.e. significantly less intense than normal T cells, B cells or monocytes. In monocytic AML expression may be stronger. | ||
CD34 | Frequently expressed by AML blast cells (40-80% of cases) - most often in less differentiated forms of AML. Note that expression is also frequent (and often stronger) in ALL | ||
Potential contribution to establishing primitive nature in AML | |||
TDT | Expressed in some cases of AML (5-20%) particularly in less differentiated blast cells, often on a sub-population of cells. More typically associated with ALL. | ||
CD7 | Similar to TdT, although more frequently expressed (20-40%) CD7 tends to be expressed by AML blasts in the more primitive forms. CD7 is most consistently a marker of T-lineage (including T-ALL). | ||
Markers useful in assigning myeloid lineage in AML
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Marker | Comment | ||
MPO | A strong lineage marker for AML when detected by flow cytometry (though potentially less so by immunocytochemistry) | ||
CD117 | One of tne of the first lineage-markers acquired in AML with good relative specificity | ||
CD33 | A good marker for AML that is often less strongly expressed in monocytic forms | ||
CD13 | A good lineage marker for AML aquired a little later, higher than CD13 in monocytic forms | ||
Other markers helpful in detecting myeloid lineage (often in AML subtypes) | |||
These markers have less general value in diagnosis, but can be useful in subtype selection or in cases whwere lineage is ambiguous. | |||
Marker | Expectation | Comment | |
CD10 | Gran | One of tne of the first lineage-markers acquired in AML with good relative specificity | |
CD11b | Gran | One of tne of the first lineage-markers acquired in AML with good relative specificity | |
CD11c | Mono | One of tne of the first lineage-markers acquired in AML with good relative specificity | |
CD14 | Mono | A good marker for AML that is often less strongly expressed in monocytic forms | |
CD64 | Mono | A good lineage marker for AML aquired a little later, higher than CD13 in monocytic forms |