Reasoning that the dosage of ETS protein is crucial in ETS-drive prostate cancer tumorigenesis, we created a low dosage (ETV4WT) level and a high dosage (ETV4AAA) level of ETV4 protein through increased ETV4 protein stability by mutating the conserved ExxVPD motifs responsible for COP1 degradation (22, 24). Here, ETV4 is linked to prostate cancer.