As activation of the β-catenin signaling pathway is known to be facilitated by PDE5 in various cancer types [26], we tested the potential involvement of PDE5 in this TIA-induced event and found that TIA reduced the expression of PDE5 (Figure 2B) while it almost completely wiped out the PDE5 protein in U87MG cells (Figure 2C). This evidence concerns the gene PDE5A and cancer.