Angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin II receptor blockers (ARBs) are commonly prescribed to the large and growing number of individuals with cancer (for example, currently more than two million in the UK[1] and 13 million in the US[2]) often to treat hypertension which affects around 40% of cancer patients[3]. This evidence concerns the gene ACE and Hypertension.