By analyzing the PDE4B gene expression levels of cases with childhood acute lymphoblastic leukemia from microarray-based gene expression profiling [45], we also found that PDE4B was highly expressed in the cases (n = 359) compared to non-leukemia and healthy bone marrow (n = 74) (Fig. 5d; Mann–Whitney U test, p value = 1.66 × 10−9). Here, PDE4B is linked to leukemia.