Figure 1.

 (A) Absence of inducible nitric oxide synthase (iNOS) expression in chronic ulcerative colitis. (B) iNOS expression is present in epithelial cells in dysplasia. (C) Absence of iNOS expression in tumour cells. (D) Fas is expressed in epithelial cells in dysplasia. (E) Fas is strongly expressed in tumour cells. (F) Bcl-xl is expressed in epithelial cells in dysplasia. (G) Bcl-xl is expressed in tumour cells. (H) Caspase 3 is activated in epithelial cells in dysplasia. (I) iNOS is expressed in tumour cells of sporadic adenocarcinoma. (J) Fas is weakly expressed in sporadic colon carcinoma tumour cells. (K) Absence of Bcl-xl expression in sporadic colon carcinoma cells. (L) Caspase 3 is activated in sporadic colon cancer tumour cells.