CD22 and precursor B-cell acute lymphoblastic leukemia: In this reported case, even though CD79a expression was severely low (CD79a, 8%), we were able to make the diagnosis of B-ALL on the basis of the expression of the other B markers included in the panel (CD19, 97%; CD10, 97%; and CD22, 67%) and, luckily, none of the other myeloid or T-cell markers were positive in this case.