This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Haematology, Subject name: Pathology
Marker for hairy cell leukaemia is? 
Select and explain. 
A. CD30, B. CD 103, C. CD 1, D. CD4
B: CD 103
Answer: B: CD 103 
Explanation: Hairy cell leukemia express CD 19 ,CD2O, CD22 antigen. In addition to Bcell markers they are also positive for CD11,CD25,CD103 Reference : Harsh Mohan textbook of pathology, 7th edition.Pg no.358