CD34 and precursor B-cell acute lymphoblastic leukemia: The gene expression profile confirmed that four cases (three CD34-negative) of B-ALL with a six-point score of three and three cases of B-ALL with a three-point score of two (one of which also had a score of three in the six-point system) all had gene expression signatures similar to the B-ALL group, confirming the diagnosis of B-ALL (Figure 3).