Silencing of EPAS1 via siRNA induced reduced cell proliferation, increased apoptosis, and generated smaller tumor in a mouse model of pancreatic carcinoma (43), whereas inhibition of EPAS1 with a small molecular target (PT2399) causes tumor regression in a preclinical mouse model of primary and metastatic clear cell renal cell carcinoma (9). Here, EPAS1 is linked to clear cell renal carcinoma.