EDNRA and neoplasm: Given that: 1) breast cancer cells secrete endothelin(ET)-1 to stimulate tumor growth;10 2) endothelin receptor type A (ETAR) is highly expressed in both cancer cells and cardiomyocytes;11, 12, 13, 14 3) activation of the endothelin system is known to contribute to cardiac remodeling and heart failure pathogenesis;11, 12, 13, 14 and 4) inhibition of endothelin signaling lessens heart failure and cardiac hypertrophy,15, 16, 17 we postulated that shared signaling pathways perpetuate endothelin axis activation in both systems.