PAX5 and precursor B-cell acute lymphoblastic leukemia: However, elevated levels of IL-6 protein could be measured at the time of B-ALL diagnosis in the serum of Pax5+/-;Sca1-ETV6-RUNX1 leukemic mice and Pax5+/-;Sca1-BCR-ABLp190 leukemic mice22 (Fig. 1, Supplementary Table S1).