NOS2 and malignant colon neoplasm: Activating mutations on codon 12 and 13 of the k-ras gene [14, 15], upregulation of cyclo-oxygenase 2 (COX-2), and inducible nitric oxide synthase (iNOS), as well as alterations in transforming growth factor β signaling, are also common features to both human and AOM-induced colon cancers [24–29].