It is important to note that mRNAs for only ten of the seventeen identified ARVs (i.e., ARQ640X, AR-V1, AR-V5, AR-V6, AR-V7, AR-V9, ARV567es, AR13, AR-V14, and AR8) have been detected in tumor samples from patients with castration-resistant prostate cancer. This evidence concerns the gene AR and prostate cancer.