In another study in which atrasentan was administered in combination with interferon (IFN)-α for the treatment of renal cell carcinoma (RCC), exploratory analysis showed that median OS worsened dramatically by 20 months in patients with increasing VEGF levels in combination with stagnant ET1 levels, compared with patients with decreasing VEGF levels (2.2 months versus 22.2 months) [108]. This evidence concerns the gene EDN1 and renal cell carcinoma.