In sharp contrast, B-ALL was significantly delayed in the IL-6+/-/Pax5+/- mice, appearing between 18 and 22 months of age (mean = 20.13 months) (Fig. 3a-b), although by the termination of the experiment a similar percentage (20%) of the mice had developed B-ALL and IL-6 was elevated in their serum similarly to IL-6+/+/Pax5+/- leukemias (Fig. 3c). Here, PAX5 is linked to precursor B-cell acute lymphoblastic leukemia.