TP53 and cancer: The connection between PDE9A expression and different clinicopathological characteristics in CRC samples exhibits that PDE9A is down-regulated in all the variables (sample types, individual cancer stages, patient’s race, patient’s weight, patient’s gender, patient’s age, histological subtype, nodal metastasis status, and TP53 mutation status) used here compared to the normal (Fig. 5 and Supplementary Table 1).