TEK and neoplasm: To rigorously determine if the antitumor effects of dual inhibition act mainly through its effects on tumor-associated ECs, we generated an EC-specific PDGFR-β-knockout mouse line, Tie2-Cre;Pdgfrbfl/fl by crossing Pdgfrbfl/fl mice with mice expressing Cre under EC-specific promoter Tie2 (Fig. 7a).