PAX5 and acute lymphoblastic leukemia: Thus, given that alteration in the expression of PAX5 and IKZF1 was shown to be one of the main causes of differentiation blockade in B-ALL, we speculate that the upregulation of PAX5 and IKZF1 by IMB treatment is associated with the differentiation of CCRF-SB B-ALL cells [25,26,27].