Acute leukaemia types

Expression guide: acute myeloid leukaemia
Markers useful to confirm the primitive phenotype (expressed in both AML and ALL) AML cells often have markers that reflect their primitive nature. 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. In AML these markers are most frequently expressed by less differentiated types. Other markers such as CD34, TdT and CD7 may be considered to reflect primitive differentiation, so while they are not required if other features fit (weak CD45 and/or blast cell morphology), detecting them can increase diagnostic confidence. Note while not fully specific for any given lineage, some are more frequently associated with particular lineages so may contribute to lineage assignment in difficult cases (see comments).
Marker	Comment
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. However, expression is less frequent and often less intense than in lymphoid leukaemias
TDT	Expressed AML particularly in less differentiated blast cells, often on a sub-population of cells. More typically associated with ALL where expression is generally stronger.
CD7	Similar to TdT, CD7 expression is recognised on a proportion of AML, usually those with less differentiated phenotype. Most consistently expressed in T-ALL.
Markers with very strong lineage specificity in AML
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).
Marker	Expectation	Comment
MPO		A strong lineage marker for AML when detected by flow cytometry (though potentially less so by immunocytochemistry)
Lineage markers in AML that with relatively high speificity
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)).
Marker	Expectation	Comment
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