In order to elucidate the significance of ERRα in the regulation of T:E fusion gene and its contribution to the malignant growth capacity of prostate cancer cells without the AR influence, we generated stable T:E fusion-transduced infectants in three AR-negative prostatic cell lines (PC-3, BPH-1, and NCI-H660) using a T:E fusion expression plasmid pLenti-P-T:E, in which the ERG expression was driven specifically by a fragment of ERRα-regulating T:E promoter containing the P1 ERRα-binding site (Fig. 6a). Here, ERG is linked to prostate cancer.