AR and metastatic neoplasm: An important aspect of CRPC is reactivation of androgen-receptor (AR) signaling, as demonstrated by analyses of metastatic tumors showing that essentially all known androgen regulated genes are expressed, including putative drivers of carcinogenesis (e.g., Transmembrane Protease, Serine 2-ETS-related gene (TMPRSS2-ERG) rearrangements).