Acute leukaemia types: Difference between revisions
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|colspan="2" style = "font-size:90%; color:black;" |'''Mixed Phenotype Acute leukaemia (MPAL)''' | |colspan="2" style = "font-size:90%; color:black;" |'''Mixed Phenotype Acute leukaemia (MPAL)''' | ||
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|colspan="2" style = "font-size:84%;"|Formerly known as leukaemia of ambiguous lineage | |colspan="2" style = "font-size:84%;"|Formerly known as leukaemia of ambiguous lineage: Myeloid MPO or monocytic defined by at least two markers (CD14, CD11c, CD64, NSE, lysozyme. T lineage CD3 (s or m), STRONG Cd19, with strong CD79a cCD22 or CD10 OR wk CD19 also with obove | ||
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|colspan="2" style = "font-size:90%; color:black;" |'''Early T-precursor acute lymphoblastic leukaemia (ETP-ALL)''' | |colspan="2" style = "font-size:90%; color:black;" |'''Early T-precursor acute lymphoblastic leukaemia (ETP-ALL)''' |
Revision as of 17:04, 24 July 2023
Sections
- Establishing the primitive nature of AML blast cells (CD45 gating and primitive markers) click to visit section
- The AML phenotype (expected markers expressed by most AML cases or those with specific differetiation) click to visit section
- Abberent markers in AML (Abberrent makers that are frequently encountered) click to visit section
- Important additional notes 1: recognising difficult subtypes 2: clues suggesting MPAL or ETP-ALL) click to visit section
(note: for further information on any marker or section click the blue highlighted text)
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MARKERS USEFUL TO CONFIRM PRIMITIVE NATURE OF BLAST CELLS | |
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Useful markers of primitive nature
(1) Typically AML blasts have low CD45 expression and cause low side scatter. This means that they form a relatively uniform and distinctive population that is clearly separate from that of lymphocytes on CD45/SSc plots (for further details see this section) also not all AML forms may fit this pattern - particularly APL and monocytic AML. | |
CD45 | A marker expressed by all leukocytes and their precursors. In AML expression is characteristically "weak" i.e. significantly less intense than normal lymphocytes 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. Expression is also seein frequently (and often more strongly) in ALL |
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MARKERS USEFUL TO CONFIRM MYELOID LINEAGE OR DIFFERENTIATION | |
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Frequently expressed "general" markers of myeloid lineage
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MPO | A strong lineage marker for AML (expressed in around 80% of cases) but generally in those with granulocytic maturation. When detected by flow cytometry is diagnostic of myeloid differentiation (either AML or MPAL) |
CD117 | An early marker of myeloid lineage, seen in up to 80% of AML and vauable in recognising more primitive differentaiion forms (note that aberrant expression is seen in up to 20% of ALL cases) |
CD33 | A good marker for AML, particularly for those cases with granulocytic maturation, CD33 is often less strongly expressed in AML with monocytic dfferentiation and strongly expressed in APL. |
CD13 | A good lineage marker for AML that is acquired a little later in differentation than CD117 or CD33; expression of CD13 is often higher than CD33 in AML with monocytic differentiation. |
Confirmatory markers of AML or markers of subtype
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Granulocytic lineage markers | |
CD10 | One of tne of the first lineage-markers acquired in AML with good relative specificity |
CD11b | One of tne of the first lineage-markers acquired in AML with good relative specificity |
Monocytic lineage markers | |
CD11c | One of tne of the first lineage-markers acquired in AML with good relative specificity |
CD14 | A good marker for AML that is often less strongly expressed in monocytic forms |
CD64 | A good lineage marker for AML aquired a little later, higher than CD13 in monocytic forms |
Erythroid lineage markers | |
CD14 | A good marker for AML that is often less strongly expressed in monocytic forms |
CD64 | A good lineage marker for AML aquired a little later, higher than CD13 in monocytic forms |
Megakaryocytic lineage markers | |
CD14 | A good marker for AML that is often less strongly expressed in monocytic forms |
CD64 | A good lineage marker for AML aquired a little later, higher than CD13 in monocytic forms
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NON MYELOID MARKERS FREQUENTLY "ABERENTLY" EXPRESSED IN AML | |
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Markers of lymphoid lineage indicating primitive dfferentiation in AML
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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 primitive ALL blast cells. |
CD7 | Predominantly seen as a T-cell antigen, CD7 tends may be expressed by AML blasts (20-40%) where it most often indicates a more primitive forms or MPAL. CD7 is most consistently a marker of T-lineage (including T-ALL and more mature froms). |
Markers of lymphoid differentation abererantly expressed in AML
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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 primitive ALL blast cells. |
CD7 | Predominantly seen as a T-cell antigen, CD7 tends may be expressed by AML blasts (20-40%) where it most often indicates a more primitive forms or MPAL. CD7 is most consistently a marker of T-lineage (including T-ALL and more mature froms). |
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IMPORTANT ADDITIONAL POINTS | |
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AML subtypes with distinctive phenotype
(1) Typically AML blasts have low CD45 expression and cause low side scatter. This means that they form a relatively uniform and distinctive population that is clearly separate from that of lymphocytes on CD45/SSc plots (for further details see this section) also not all AML forms may fit this pattern - particularly APL and monocytic AML. | |
Mixed Phenotype Acute leukaemia (MPAL) | |
Formerly known as leukaemia of ambiguous lineage | |
Early T-precursor acute lymphoblastic leukaemia (ETP-ALL) | |
A (relatively new entity) | |
Acute leukaemia types with features of mixed phenotype
(1) Typically AML blasts have low CD45 expression and cause low side scatter. This means that they form a relatively uniform and distinctive population that is clearly separate from that of lymphocytes on CD45/SSc plots (for further details see this section) also not all AML forms may fit this pattern - particularly APL and monocytic AML. | |
Mixed Phenotype Acute leukaemia (MPAL) | |
Formerly known as leukaemia of ambiguous lineage: Myeloid MPO or monocytic defined by at least two markers (CD14, CD11c, CD64, NSE, lysozyme. T lineage CD3 (s or m), STRONG Cd19, with strong CD79a cCD22 or CD10 OR wk CD19 also with obove | |
Early T-precursor acute lymphoblastic leukaemia (ETP-ALL) | |
A (relatively new entity) | |
Non-haematopoietic tumours | |
need to know problems |