In colorectal cancer and familial adenomatous polyposis (FAP), COX-2 inhibition has been shown to inhibit the development of invasive cancer and reduce the frequency of polyp formation (Giardiello et al, 1993; Steinbach et al, 2000; Phillips et al, 2002; Asano and McLeod, 2004). This evidence concerns the gene PTGS2 and colorectal cancer.