Interactions of the renin-angiotensin system in colorectal cancer and metastasis.

The novel function of the renin-angiotensin system (RAS) is cardiovascular homeostasis. While the major active mediator angiotensin II (ANG II) produces most of the physiologic responses via angiotensin II type I receptor (AT1R), recent insights have looked at the implications of ANG II and its impact on solid tumor formation. Preclinical studies have demonstrated the direct effect of ANG II on the stimulation of angiogenesis via VEGF and other proliferative mediators. RAS components have thus been identified in numerous malignant tissues. Inhibition of the AT1R via angiotensin-converting enzyme inhibitors (ACE-Is) has demonstrated a decrease in solid tumor development and metastasis. Numerous retrospective analyses have demonstrated a reduction in colorectal cancer incidence, polyp formation, and distant metastasis in patients taking inhibitors of the RAS. The use of commonly prescribed anti-hypertensive medications as a chemo-preventative medication may have a remarkable impact in the colorectal cancer community. Further investigation and prospective clinical trials may provide further insight into the potentially beneficial use of ACE-Is and their impact on colorectal cancer.