ET-1 has been shown to stimulate the growth of several human cancer cell lines in vitro including colorectal, ovarian, prostate, Kaposi's sarcoma and melanoma cells (Yohn et al, 1994; Nelson et al, 1996; Bagnato et al, 1999; Ali et al, 2000b; Bagnato et al, 2001). Here, EDN1 is linked to Kaposi's sarcoma.