IV. To analyze the effects of these agents on the following panel of mucosal biomarkers: antigen identified by monoclonal antibody Ki-67 (Ki-67), mitotic index (number and spatial distribution of mitoses), phosphorylated histone H3, cyclin-dependent kinase inhibitor 1A (p21/WAF1/Cip1), apoptosis (Terminal deoxynucleotidyl transferase dUTP nick end labeling [TUNEL]), apoptotic index, BCL2-associated X protein (Bax), B-cell CLL/lymphoma 2 (Bcl-2) and measurement of drug effects in colonic polyp and normal tissue cyclooxygenase (cyclooxygenase-1 [COX-1], cyclooxygenase-2 [COX-2]) protein levels, prostaglandin E2 (PGE2), ornithine decarboxylase and polyamines.