Consistent with these opposing directions of effect, in vivo calcitonin receptor-like inhibition has been shown to reduce tumor growth in solid tumors but to increase atherosclerotic lesions.46,47 Calcitonin receptor-like antagonists have recently emerged as effective medications for the treatment of migraine disorder.48–50 Our findings suggesting potential opposing roles of calcitonin receptor-like in CAD and breast cancer development support continued safety monitoring of calcitonin receptor-like antagonists to evaluate the potential consequences of their long-term use. This evidence concerns the gene CALCRL and breast cancer.