NKX3-1 and neoplasm: We have shown that stable expression of dominant negative ARΔTR inhibits endogenous AR-H874Y transcriptional activity and slows or delays CWR-R1 tumor growth in the absence and presence of supplemental T. Dominant negative ARΔTR activity was also indicated by the decrease in Nkx3.1 protein and luciferase reporter activity in the presence of DHT.