PDE4B and malignant colon neoplasm: In addition, PDE4B was also found to have a positive effect on hematological tumor (Nagy et al., 2013), colon cancer (Nishi et al., 2017), lung cancer (Pullamsetti et al., 2013), liver cancer (Ding et al., 2012), etc. The only special case so far is the reduced expression of PDE4B in prostate cancer (Henderson et al., 2014).