An increasing body of evidences witnesses that the ET-1 system takes part in the reprogramming of the microenvironmental cell behavior affecting cancer-associated fibroblasts (CAF) [60–62] and different subtypes of immune effectors, including competent dendritic cells (DC) [63], tumor-associated macrophages (TAM) [63–65], and tumor-infiltrating lymphocytes (TIL) [66], regulating their maturation and activity [60–65] or interfering with their recruitment to the tumor [66]. This evidence concerns the gene EDN1 and cancer.