AR and prostate cancer: We next tackleda more challenging target, the truncated and constitutivelyactive mutant of androgen receptor (AR), AR-V7, that drives the pathogenesisof androgen-resistant prostate cancers.37 AR-V7 is a relatively undruggable target, given that the ligandbinding domain that is the target of most AR-targeting drugs is missingfrom AR-V7.