The findings of AKT dephosphorylation by PDE4 inhibitor, rolipram or PDE4B2-shRNAs in HCT116 cells in 3 DC, but not in HCT116 cells in 2 DC (Figure 4 and 5), suggesting the 3-D specific action of PDE4B2 for cancer cells with oncogenic KRAS. This evidence concerns the gene PDE4A and cancer.