Actions

Difference between revisions of "CD34"

From www.haemtologyetc.co.uk

 
(3 intermediate revisions by the same user not shown)
Line 30: Line 30:
 
<span style="color:navy">'''Other relevant information:'''</span>  
 
<span style="color:navy">'''Other relevant information:'''</span>  
  
Histopathologists often use CD34 to demonstrate the number of primitive cells in bone marrow trephine biopsies e.g. in the assessment of primitive cell number in myelodysplaia, however a range of other cell types also express this marker. In marrow these include: vascular endothelial cells and mast cells  
+
Histopathologists often use CD34 to demonstrate the number of primitive cells in bone marrow trephine biopsies e.g. in the assessment of primitive cell number in myelodysplaia, however a range of other cell types also express this marker. In marrow these include: vascular endothelial cells and mast cells.
  
  
Line 51: Line 51:
 
</gallery>
 
</gallery>
  
<span style="font-size:80%">'In AML expression is rare in APL, and is less frequent in NPM1-mutated patients</span>
+
<span style="font-size:80%">''* In AML expression is rare in APL, and is less frequent in NPM1-mutated patients''</span>
  
  

Latest revision as of 15:05, 10 October 2019


  • Expressed by many cases of ALL (around 50%) and AML (around 40%)
  • Very rare cases of primitive leukaemia may solely express CD34 and CD45
  • It is expressed by regenerating cells in marrow (particularly by haematogones)




What is its normal function and expression?

CD34 is a membrane protein, in bone marrow CD34 expressed on haematopoietic stem cells is likely to play a role in glycan-mediated homing or retention within the “stem cell niche” and may contribute to their subsequent maturation. CD34 can be viewed as a marker of “primitiveness” - it is acquired at the stage of pluripotent stem cells (CD34+ CD38-) and is retained by committed stem cells (CD34+ CD38+) before being lost as the cells mature. It is also expressed by mast cells and some non-haematopoietic cells (particularly endothelial cells).


What is its diagnostic role?

  • CD34 is commonly expressed by ALL (around 50%) and in AML expression (around 40%)
  • Rare very primitive cases of acute leukaemia may be identified solely through their expression of CD34 and CD45
  • CD45 is expressed by regenerating blast cells (CD45 weak and low side scatter), and also by haematogones (intermediate CD45 and low side scatter)


Other relevant information:

Histopathologists often use CD34 to demonstrate the number of primitive cells in bone marrow trephine biopsies e.g. in the assessment of primitive cell number in myelodysplaia, however a range of other cell types also express this marker. In marrow these include: vascular endothelial cells and mast cells.



SUMMARY TABLES


1. Expression by acute leukaemias and by haematogones

* In AML expression is rare in APL, and is less frequent in NPM1-mutated patients


2. Expression by B-lymphoproliferative disorders



KEY


The indicated expression frequency, indicates the approximate frequency of occurrence in each particular disease type.


Rare.png

rare (<5%)

Poss.png

possible (5-20%)

Mod.png

likely (20-40%)

Freq.png

frequent (40-80%)

Hi.png

expected (>80%)


Where expression level is unusual or characteristic of a disorder this is indicated by text: