This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Pathology
The blast cells of acute lymphocytic leukemia in childhood contain 
Select and explain. 
A. Surface antigen, B. CALLA Ag, C. Antibodies to WBC, D. Thrombocytopenia
B: CALLA Ag
Answer: B: CALLA Ag 
Explanation: CALLA (common acute lymptoblastic leukemia antigen) is CDIO
CALLA positive acute leukemias have best progrosis.