For the PBX group (see Figure 4), we observed that PBX1 and PBX3 were, to some extent, up-regulated in patients with ALL, but this difference was only statistically significant when we normalized with reference gene RPL32. PBX2 expression remained unchanged in patients and controls, and the sole member that clearly exhibited down-regulation in ALL samples was PBX4. The gene discussed is PBX4; the disease is acute lymphoblastic leukemia.