The S-phase cell cycle block of CRC cells following mesalazine treatment is preceded by the rapid ubiquitination and proteasome-dependent degradation of CDC25A, a phosphatase that is over-expressed in the majority of CRC cells and that is known to regulate the G1/S transition and S phase progression through the modulation of different cyclin/cyclin-dependent kinase (CDK) complexes [71]. Here, CDC25A is linked to colorectal carcinoma.