To measure the effect of 5-ASA on β-catenin/TCF-mediated transcription activity in adenoma-derived cells, we treated PC/AA/C1 (APC mutant) adenoma-derived cells with 5-ASA after transfection with TOPflash and FOPflash reporter plasmids and compared it to LS174T (β-catenin mutant) carcinoma-derived cells. The gene discussed is APC; the disease is carcinoma.