PDE4D and colorectal carcinoma: Concerning the number of PDE4D-positive cells in lamina propria, a statistically significant difference was observed between control and CRC stage Dukes’ A, C, and D, as well as CRC stage Dukes’ B and CRC stage Dukes’ A, C, and D. Additionally, CRC stage Dukes’ A had significantly more PDE4D-positive cells in the lamina propria than in the CRC stage Dukes’ D (Figure 4f).