Several reports indicate that mesalazine (5-aminosalicylic acid or 5-ASA) is a promising candidate for the chemoprevention of Colo-Rectal Cancer (CRC) due to its ability to reach the purpose, yet avoiding at the same time the side effects that are usually determined by prolonged administrations of Non Steroidal Anti-Inflammatory Drugs. This activity of 5-ASA is probably the consequence of a number of effects determined on colon cancer cells and consisting of reduced proliferation, increased apoptosis and activation of cell cycle checkpoints. A recent observation has suggested that these effects could be mediated by the capacity of 5-ASA to interfere with the nuclear translocation of beta-catenin, in turn responsible for the inhibition of its transcription activity. The aim of our study was to better characterize the molecular mechanism by which 5-ASA inhibits the beta-catenin signaling pathway. To address this issue we assessed, by means of the Affymetrix microarray methodology, the transcriptome changes determined on Caco2 cells by a 96 h treatment with 20 mM mesalazine.