REN and colorectal carcinoma: In this model, the activation of the renin-angiotensin system and subsequent augmentation of chronic inflammation and oxidative stress enhanced the development of AOM-induced colonic premalignant lesions, aberrant crypt foci (ACF), which indicated that the model was useful to test the potential efficacy of renin-angiotensin system inhibitors in preventing CRC development in patients with Mets (10).