CD34 and acute lymphoblastic leukemia: The core set of antibodies used to compound the backbone in the different combinations useful for MRD detection in B-lineage ALL (B-ALL) usually include CD45, CD34, CD19, and CD10 - antigen initially named CALLA (common ALL antigen), expressed with high frequency in childhood BALL.5,13,24,29,36,41,50,54,56 The additional antibodies should be chosen based on the immunophenotype of each case at diagnosis.