Since ETAR is the receptor that is overexpressed in most cancers [10], clinical trials have been conducted with various ETAR antagonists such as atrasentan and zibotentan in various solid cancers such as glioma, metastatic and non-metastatic prostate cancer, lung, ovarian and renal cell cancer as monotherapy or in combination with chemotherapy [103–109] (Table 1). The gene discussed is EDNRA; the disease is glioma.