Recently, it has been reported that COX-2 expression is induced in hamartomatous polyps of PJS patients and Lkb1+/− mice (Rossi et al, 2002; de Leng et al, 2003; McGarrity et al, 2003), suggesting the roles of COX-2 in hamartoma development. This evidence concerns the gene STK11 and Peutz-Jeghers syndrome.