The effects of cancer therapeutics on the circulatory system are broad and some of what is perceived as being cardiotoxicity may not be solely due to a direct effect on the myocardium, but may be due to concomitant effects on the vasculature, particularly the endothelium.14,27,28 One illustrating example where this might come into play is in patients undergoing HER-2-directed therapy. Here, ERBB2 is linked to cancer.