AR and cancer: Selective and potent anticancer activities in range of cancer cell lines, with reported antiproliferative and proapoptotic actions. Induces unfolded protein response and autophagy. Mimics RNAi-mediated knockdown of Sigma1. Triggers lysosomal and proteasomal degradation of cancer promoting signaling proteins including PD-L1, ErbB receptors, and androgen receptor. Multiple high and low-affinity Sigma1-binding sites with distinct activities in intact cancer cells identified. Radiolabeled IPAG tracer used as selective in vivo tumor imaging agent.