AR and neoplasm: In a prospective study of patients with metastatic CRPC treated with first-line abiraterone, an RNA-based signature derived from circulating tumor cells, pretreatment expression of HOXB13, which controls a malignant AR cistrome [47], identified patients with poor overall survival, with a subset also expressing the ARV7 splice variant, a version of AR lacking a function LBD [122].