Differential response of flat and polypoid colitis-associated colorectal neoplasias to chemopreventive agents and heterocyclic amines.

Individuals with ulcerative colitis face an increased risk of developing colorectal cancer and would benefit from early chemopreventive intervention. Results from preclinical studies in the mouse model of dextran sulfate sodium-induced colitis demonstrate that flat and polypoid colitis-associated dysplasias arise via distinct genetic pathways, impacted by the allelic status of p53. Furthermore, flat and polypoid dysplasias vary in their response to induction by the heterocyclic amine 2-amino-3-methylimidazo[4,5-f]quinoline (IQ) and inhibition by 5-aminosalicylic acid, a common therapy for the maintenance of colitis patients. These data suggest that use of combination therapy is essential for the optimal inhibition of colitis-associated colorectal cancer.